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Add to My Garden Mexican petunia
Ruellia simplex
Also known as: Texas Petunia, Mexican blue bells, Britton's wild petunia
Mexican petunia (Ruellia simplex) is an evergreen herbaceous perennial recognized by its wrinkly, trumpet-shaped purple flowers. It is commonly cultivated as an ornamental plant. Due to its vigorous spreading ability, Ruellia simplex has become widely naturalized outside Mexico. It is considered an invasive species in many countries.
Twice per week
Water
Full sun
Sunlight
Care Guide for Mexican petunia
Though Mexican petunia is drought tolerant, it still does best in soil that is consistently moist. Water about twice each week to keep the soil from drying out. However, the exact watering schedule will vary depending on the weather conditions. When transplanting or dealing with tender young plants, water Mexican petunia more often and deeply.
Mexican petunia doesn't require fertilizer but will enjoy the extra boost. Feed it with a tablespoon of 10-10-10 fertilizer occasionally throughout the flowering season.
Trim the diseased, withered leaves once a month.
Loam
Needs excellent drainage in pots.
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Mexican petunia
Water
Twice per week
Sunlight
Full sun
Hardiness Zones
8 to 11
Planting Time
Spring, Summer
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Mexican petunia
Water
Twice per week
Sunlight
Full sun
Hardiness Zones
8 to 11
Planting Time
Spring, Summer
Download
Mexican petunia
Water
Twice per week
Sunlight
Full sun
Hardiness Zones
8 to 11
Planting Time
Spring, Summer
Download
Questions About Mexican petunia
Watering 
Pruning 
Sunlight 
Temperature 
Fertilizing What is the best way to water my Mexican petunia?
When watering the Mexican petunia, you should aim to use filtered water that is at room temperature. Filtered water is better for this plant, as tap water can contain particles that are harmful to its health. The reason that the water should be at room temperature or slightly warmer is that the Mexican petunia comes from a warm environment, and cold water can be somewhat of a shock to its system. Also, you should avoid overhead watering for this plant, as it can cause foliage complications. Instead, simply apply your filtered room temperature water to the soil until the soil is entirely soaked. Soaking the soil can be very beneficial for this plant as it moistens the roots and helps them continue to spread through the soil and collect the nutrients they need.
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What should I do if I water my Mexican petunia too much or too little?
Both overwatering and underwatering will be detrimental to the health of your Mexican petunia, but overwatering is a far more common issue. When this species receives too much water, its stems and leaves may begin to wilt and turn from green to yellow. Overwatering over a prolonged period may also lead to diseases such as root rot, mold, and mildew, all of which can kill your plant. Underwatering is far less common for the Mexican petunia, as this plant has decent drought tolerance. However, underwatering remains a possibility, and when it occurs, you can expect to find that the leaves of your Mexican petunia have become brittle and brown.
It is crucial that you notice the signs of overwatering as soon as possible when caring for your Mexican petunia. Some of the diseases that arise from overwatering, such as root rot, may not be correctable if you wait too long. If you see early signs of overwatering, you should reduce your watering schedule immediately. You may also want to assess the quality of soil in which your Mexican petunia grows. If you find that the soil drains very poorly, you should replace it immediately with a loose, well-draining potting mix. On the other hand, if you find signs that your Mexican petunia is receiving too little water, all you need to do is water more regularly until those signs have subsided.
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How often should I water my Mexican petunia?
If your plant is in a pot. The most precise way to decide whether your Mexican petunia needs water is to plunge your finger into the soil. If you notice that the first two to three inches of soil have become dry, it is time to add some water.
If you grow your Mexican petunia outdoors in the ground, you can use a similar method to test the soil. Again, when you find that the first few inches of soil have dried out, it is time to add water. During the spring and early fall, this method will often lead you to water this plant about once every week. When extremely hot weather arrives, you may need to increase your watering frequency to about twice or more per week. With that said, mature, well-established the Mexican petunia can show an admirable ability to withstand drought.
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How much water does my Mexican petunia need?
When it comes time to water your Mexican petunia, you should not be shy about how much water you give. With the first two to three inches of soil dry, this plant will appreciate a long and thorough watering. Supply enough water to soak the soil entirely. The amount of water you add should be enough to cause excess water to flow through the drainage holes at the bottom of your pot. If you don’t see excess water draining from the pot, you have likely underwatered your plant. But do not let the water accumulate inside the soil, which will be very dangerous to the plant as well. Alternatively, a lack of water draining through the pot could indicate poorly draining soils, which is detrimental to the health of this plant and should be avoided. If the plant is outside, 1 inch of rain per week will be sufficient.
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How should I water my Mexican petunia at different growth stages?
The water needs of the Mexican petunia can change depending on growth stages as well. For example, when your Mexican petunia is in the first few years of its life, or if you have just transplanted it to a new growing location, you will need to give more water than usual. During both of those stages, your Mexican petunia will put a lot of energy towards sprouting new roots that will then support future growth. For those roots to perform their best, they need a bit more moisture than they would at a more mature phase. After a few seasons, your Mexican petunia will need much less water. Another growth stage in which this plant may need more water is during the bloom period. Flower development can make use of a significant amount of moisture, which is why you might need to give your Mexican petunia more water at this time.
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How should I water my Mexican petunia through the seasons?
The Mexican petunia will have its highest water needs during the hottest months of the year. During the height of summer, you may need to give this plant water more than once per week, depending on how fast the soil dries out. The opposite is true during the winter. In winter, your plant will enter a dormant phase, in which it will need far less water than usual. In fact, you may not need to water this plant at all during the winter months. However, if you do water during winter, you should not do so more than about once per month. Watering too much at this time will make it more likely that your Mexican petunia will contract a disease.
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What's the difference between watering my Mexican petunia indoors and outdoors?
It is most common to grow the Mexican petunia indoors for any gardener that does not live in temperate and tropical regions. Those gardeners should consider the fact that soil in a container can dry out a bit faster than ground soil. Also, the presence of drying elements such as air conditioning units can cause your Mexican petunia to need water on a more frequent basis as well. if you planted it outside. When that is the case, it’s likely you won’t need to water your Mexican petunia very much at all. If you receive rainfall on a regular basis, that may be enough to keep your plant alive. Alternatively, those who grow this plant inside will need to water it more often, as allowing rainwater to soak the soil will not be an option.
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Common Pests & Diseases
Common issues for Mexican petunia based on 10 million real cases
Leaf beetles
Leaf beetles are a class of colored insects 1 to 2 cm in size. They gnaw on leaves and petals resulting in small, round holes scattered over the surface.
Solutions: For less serious cases: Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread. To treat more serious infestations: Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions. Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.
Flower withering
Flowers may dry out due to a sudden change in environment or because the plant has completed its normal flowering period.
Solutions: If flower withering is a natural progression due to age, there is nothing that can be done to slow or stop the process. Once hormones within the plant begin the process of senescence, it’s irreversible. For lack of water, immediately water the plant using room temperature rainwater, bottled spring water, or filtered tap water. Water container plants until excess water drains out the bottom; water in-ground plants until the soil is soaked but there isn’t standing water on the surface. In the event of nutritional deficiencies, the best solution is to use a granular or water-soluble liquid fertilizer, and apply it to the soil at about half the recommended dosage. Keep it off the leaves and make sure granular products are watered into the soil well. If the plant is infected with a bacterial or fungal pathogen, there is no course of treatment that cures the diseased plants. The best solution is to remove the infected plants and dispose of the plant material off-site. Do not put in a compost pile.
Caterpillars
Caterpillars are fleshy moth or butterfly larvae that come in an array of colors, patterns, and even hairstyles. They chew on leaves and flower petals, creating large, irregular holes.
Solutions: Even though caterpillars are diverse, they all chew on plant parts and can cause significant damage if present in large numbers. For severe cases: Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects. Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans. Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps. For less severe cases: Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water. Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.
Wilting after blooming
Flowers may wither for a variety of reasons.
Solutions: Check the soil or potting medium. Coarse textures can allow water to drain too rapidly, preventing the plant from taking up enough. If the soil and roots seem very dry, add sphagnum moss or other mediums that hold water. Water according to recommendations for each plant's species. Low humidity can be corrected by misting the plant regularly or placing it near a humidifier. Keeping it near other plants helps, too. Keep the environment consistent in terms of temperature, humidity, and lighting. Keep it away from vents, heaters, and air conditioners, and avoid moving it to locations where it will experience a temperature shock. Hot, dry heat, and cold drafts are problematic for many plants. Especially if the plant is outside, it could be experiencing heat or light stress. Try moving it to a shadier location.
Petal blight
Bacterial infections can cause flowers to become soft and rotten.
Solutions: Like other fungal diseases, the progression of petal blight is extremely difficult to stop and impossible to reverse once it infects a plant. The best course of action is to remove all damaged flowers immediately and dispose of them entirely. Do not put them in the compost pile, where spores could grow and spread.
Underwatering
Leaves may wilt for a variety of reasons.
Solutions: The easiest (and most obvious) way to address underwatering is to fully hydrate the plant. However, this must be done carefully. A common mistake that many gardeners make is to douse their underwatered plants with water. This can overwhelm the roots of the plant and shock its system, something that can be even more damaging than the lack of water to begin with. Instead, water thoroughly and slowly, taking breaks to let the water slowly saturate through the soil to get to the roots. Use room temperature water, as cold water might be too much of a shock. In the future, shorten the time between waterings. A good rule of thumb is to check the soil around each plant daily. If it’s dry to at least two inches down, it’s time to water. If a container plant is repeatedly drying out very quickly, repotting into a slower-draining container might be a good idea, too.
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Leaf beetles
Leaf beetles are a class of colored insects 1 to 2 cm in size. They gnaw on leaves and petals resulting in small, round holes scattered over the surface.
Overview
Leaf beetles range in size from 1.5 mm to 2 cm. Both adult beetles and their larvae eat the leaves of many different types of plants. There are over 35,000 different species of leaf beetles, in a variety of colors including gold, green, yellow-striped, and red striped. Some of these have been mistaken for ladybirds because of their shape and coloring. They can be oval, round, or elongated in shape. These insect pests are most active in spring and summer.
If not controlled, leaf beetles can do a lot of damage to vegetable crops and ornamental plants. They feed on the leaves, flowers, stems, roots, and fruits of different plants. They can fly, which means it's easy for them to move from one plant to another. Some species of leaf beetles only target one specific crop, while others will target many different types of plants. Although a lot of the damage that they cause is cosmetic, an infestation can weaken a plant and leave it prone to other more problematic diseases.
Symptom Analysis
The first signs of a leaf beetles infestation are small visible holes in leaves. Leaves then become discolored and dark beetle droppings can be seen. As the leaves turn yellow and brown, they will drop off the plant onto the ground. Some leaves will appear skeletonized with only the veins still remaining.
Infestation begins in spring, when the adult beetles emerge from the soil and lay their eggs on the leaves of plants. When these eggs hatch, the young nymphs start munching on the leaves as they grow up. Once leaf beetles are large and mature, they'll fall to the ground and pupate in the soil over winter before starting the cycle all over again.
Leaf beetles also eat holes in fruits and vegetables. These can be seen as small round holes that sometimes have a larger brown area surrounding them.
Solutions
For less serious cases:
- Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread.
To treat more serious infestations:
- Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions.
- Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.
Prevention
To prevent infestations of leaf beetles, follow these practices.
- Regularly check for beetles. To prevent large pest infestations, be proactive about frequently checking plants for pests and removing them quickly.
- Clear debris. Clear weeds and debris to remove areas where these beetles may overwinter and hide.
- Attract natural predators. Birds and other insects, such as wasps and ladybugs, are effective natural predators of leaf beetles. Encourage them to visit by including a diverse array of plants to provide habitat and food. Also, avoid applying broad-spectrum herbicides that can harm and kill beneficial insects.
- Plant aromatic herbs like mint, garlic, or rosemary, as these can repel leaf beetles.
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Flower withering
Flowers may dry out due to a sudden change in environment or because the plant has completed its normal flowering period.
Overview
Flower withering occurs when flowers become weak, droopy, wilted, or faded until they can’t be revived. During withering, they begin to wrinkle and shrink until the flower becomes completely dry or dead.
Any flowers, regardless of the plant type or the climate they are grown in, are susceptible to withering. It is a worldwide problem across houseplants, herbs, flowering ornamentals, trees, shrubs, garden vegetables, and food crops.
Unlike wilting—which withering is often confused with—withering can be caused by different things and is often due to more than a lack of water. Withering can be fatal in severe cases.
Symptom Analysis
Flower withering progresses from very mild cases to severe occurrences that kill the flower. The severity of the symptoms is related to the cause and how long the condition is allowed to progress before action is taken.
- Wilted, droopy flowers
- Petals and leaves begin to wrinkle
- Brown papery streaks or spots appear on the petals and leaf tips
- Flowerhead shrink in size
- Petal color fades
- Yellowing leaves
- Complete death of the flower
Disease Cause
The main causes of flower withering include natural age progress, lack of water, nutritional deficiencies, and bacterial or fungal diseases. It’s critical to determine the underlying cause when flower withering is noticed. This will guide the best course of action, if treatment is possible.
Check the soil for moisture and then closely examine the entire plant for signs of nutrient deficiencies. If neither of those appears to be the cause then cut open the stem below a flower. If a cross-section reveals brown or rust-colored stains it is safe to assume that this is a bacterial or fungal infection.
If the flower is nearing the end of its normal lifespan, genetic coding within the plant increases the production of ethylene, a phytohormone that controls senescence, or cell aging and death. Cell division stops and the plant begins breaking down resources within the flower to use in other parts of the plant.
In all other cases, flower withering happens when the plant seals off the stem as a defense mechanism, stopping transport within the vascular system. This prevents further water loss through the flowers but also stops bacteria and fungi from moving to healthy parts of the plant. Once water and nutrient transport stops, the flower begins to wither and ultimately die.
Solutions
If flower withering is a natural progression due to age, there is nothing that can be done to slow or stop the process. Once hormones within the plant begin the process of senescence, it’s irreversible.
For lack of water, immediately water the plant using room temperature rainwater, bottled spring water, or filtered tap water. Water container plants until excess water drains out the bottom; water in-ground plants until the soil is soaked but there isn’t standing water on the surface.
In the event of nutritional deficiencies, the best solution is to use a granular or water-soluble liquid fertilizer, and apply it to the soil at about half the recommended dosage. Keep it off the leaves and make sure granular products are watered into the soil well.
If the plant is infected with a bacterial or fungal pathogen, there is no course of treatment that cures the diseased plants. The best solution is to remove the infected plants and dispose of the plant material off-site. Do not put in a compost pile.
Prevention
This is definitely one of those instances where prevention is more effective than cure. Here are some preventative measures for avoiding premature flower withering.
- Water plants according to their needs -- either keep the soil slightly moist or allow the top inch or two to dry out before watering again.
- Fertilize lightly on a consistent basis, depending upon the plant’s growth. Quick-growing plants and those that flower or develop fruit will need more frequent fertilizing than slow-growing plants.
- Purchase plants that are certified disease- or pathogen-free.
- Look for disease-resistant cultivars.
- Isolate plants showing disease symptoms to prevent the spread to neighboring plants.
- Practice good plant hygiene by removing any fallen plant material as soon as possible.
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Caterpillars
Caterpillars are fleshy moth or butterfly larvae that come in an array of colors, patterns, and even hairstyles. They chew on leaves and flower petals, creating large, irregular holes.
Overview
Caterpillars can cause problems for home gardeners. If not managed, these insects can defoliate a plant in just a matter of days. However, home gardeners face a challenge because these caterpillars eventually turn into beautiful butterflies and moths, which are important for pollination and the general ecosystem.
There are thousands of different species of caterpillars and many will only target certain plants. If caterpillars are posing a problem, they can be removed by hand, or gardeners can use insect-proof netting to protect their valuable plants.
Symptom Analysis
Caterpillars are the larvae of butterflies and moths. During the warmer months, butterflies and moths that visit gardens will lay their eggs on the underside of leaves.
When the tiny eggs hatch, the young larvae emerge and start feeding on the leaves of the plant. Depending on how many larvae have hatched, they can easily defoliate the plant in a very short period of time. Caterpillars will shed their skin as they grow, around 4 or 5 times during this feeding cycle.
Symptoms of caterpillars eating plants appear as holes in the leaves. The edges of the leaves may be eaten away as well, and flowers can be affected as well.
Some are easy to see, but others need to be searched for. This is because their bodies are often camouflaged to look like part of the plant. Gardeners need to look carefully along the stems of the plant as well as under the leaves. Also, look for tiny white, yellow, or brown eggs that can be found in groups on the underside of leaves.
Once the caterpillar is fully grown, it transforms into a pupa or chrysalis. Then, after a period of time that varies according to the species, a butterfly or moth will emerge from the pupa and the cycle begins again.
Solutions
Even though caterpillars are diverse, they all chew on plant parts and can cause significant damage if present in large numbers.
For severe cases:
- Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects.
- Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans.
- Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps.
For less severe cases:
- Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water.
- Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.
Prevention
Prevention may require less effort than attempts to eradicate infestations that have already begun. Here are our top steps for prevention:
- Monitor plants. Check plants regularly for caterpillar eggs on leaves. If they do not belong to an endangered species, they should be squished.
- Use insect netting. Cover plants with insect netting to prevent butterflies and moths from laying eggs on plants.
- Apply diatomaceous earth. Apply DE to plants early in the season and reapply after rain.
- Encourage plant diversity. This will attract predatory insects including parasitic wasps.
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Wilting after blooming
Flowers may wither for a variety of reasons.
Overview
Wilting after blooming is sometimes a natural aging process of the flower, while other times it may indicate a problem. Orchids, for example, can bloom for anywhere from two weeks to three months, so wilting after a few days signals a problem for most varieties. This can happen to virtually any ornamental flowering plant, but those with shallow roots and limited tolerance for drought, full sun, and low humidity are more susceptible.
This is a common problem, and often has an easy fix. Sometimes, however, it is the result of more serious causes such as pests or disease of the root system.
Symptom Analysis
- At first, flowers may look a little limp.
- Petals may start to appear dried out and turn brown.
- Eventually they may drop off the plant all together.
Disease Cause
Wilting blooms can be a sign of an unhealthy root system. Any condition that prevents the plant from absorbing enough water and nutrition can result in wilting blooms and sometimes other symptoms. If the plant doesn’t have enough water, it cannot maintain appropriate pressure within stems, leaves, and blooms, causing them to wilt.
This can result from physical damage – for example from root breakage during re-potting or attack by insects like cutworms. If you recently re-potted your plant, physical damage to the roots is a likely cause. If you see insects, they may be eating leaves, roots, or flowers. Fungal infections can also cause root rot and damage, preventing water and nutrient uptake.
Finally, wilting blooms can result simply from age. If no other symptoms are visible, it may simply signal the natural end of the flower’s lifespan. If it seems premature, this may be caused by environmental factors: water, humidity, light, or stress. Under-watering is a common cause. Similarly, plants adapted to high humidity dry out easily when humidity is low, like during winter or in dry climates. Too much light can also stress plants that need shade, causing blooms to wilt.
Solutions
- Check the soil or potting medium. Coarse textures can allow water to drain too rapidly, preventing the plant from taking up enough. If the soil and roots seem very dry, add sphagnum moss or other mediums that hold water.
- Water according to recommendations for each plant's species.
- Low humidity can be corrected by misting the plant regularly or placing it near a humidifier. Keeping it near other plants helps, too.
- Keep the environment consistent in terms of temperature, humidity, and lighting. Keep it away from vents, heaters, and air conditioners, and avoid moving it to locations where it will experience a temperature shock. Hot, dry heat, and cold drafts are problematic for many plants.
- Especially if the plant is outside, it could be experiencing heat or light stress. Try moving it to a shadier location.
Prevention
- Read up on moisture, light, and soil type preferences for each plant to avoid underwatering, incorrect light levels, or other conditions that can cause wilting blooms.
- Avoid re-potting during the flowering period. This causes additional stress on the plants because they need to repair root damage and adapt to the new micro-environment, all of which can result in wilting.
- One other potential cause is ethylene gas, a plant hormone related to ripening. Some fruits and vegetables emit ethylene, especially bananas. Apples, grapes, melons, avocados, and potatoes can also give it off, so keep flowering plants away from fresh produce.
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Petal blight
Bacterial infections can cause flowers to become soft and rotten.
Overview
Petal blight, sometimes called flower blight, is a fungal disease that only affects the blooms of some ornamental flowering plants. As the infection progresses, it destroys the flower, yet it never damages the vegetative or green parts of the plant.
When flowers are infected, the symptoms look similar to Botrytis blight, but Botrytis also infects dead or dormant vegetative tissue.
The disease was first discovered in Japanese plants in 1919 and in the US in the late 1930s. Presently it is also found in New Zealand, Australia, and parts of Europe. Unfortunately, no plants have high resistance to petal blight, but specific cultivars are more susceptible than others, particularly species with double blooms.
Petal blight infection rates are high when temperatures are mild to warm (optimum temperatures are 15 to 21 ℃) and the weather is misty or rainy.
Overall, petal blight is an aesthetic problem that ruins blossoms. The disease is not harmful to the long-term health of the plant.
Symptom Analysis
The severity of the symptoms varies, depending upon the species of plant infected. Signs of petal blight are commonly seen on the blooms just after they open.
- Pallid spots on colored petals.
- Brown spots on white petals.
- Browning around the petal edges.
- Small spots look water-soaked.
- Spots rapidly enlarge and merge.
- Flowers become limp.
- The entire flower turns light brown, but does not crumble.
- Flowers become slimy at first and then take on a leathery texture.
- A ring of white or gray mycelium can be seen at the base of the petals.
Disease Cause
Petal blight is caused by several different fungi, with each type infecting specific plants. Ovulinia azalea infects azaleas species and cultivars, and rhododendrons. Ciborinia camelliae infects camellia cultivars.
Shortly after blooming, the fungus infects the base of the flowers by the calyx. The fungus produces cell wall-degrading enzymes that destroy flowers within a couple of days. When the flowers fall to the ground, the fungus' hard fruiting bodies fall to the soil as well, overwintering until the following spring.
When temperatures hit the optimum range the following season, spores are transmitted by insects or can spread on wind currents up to about 12 miles. Once in the soil, the pathogen can be active for three to five years.
Solutions
Like other fungal diseases, the progression of petal blight is extremely difficult to stop and impossible to reverse once it infects a plant. The best course of action is to remove all damaged flowers immediately and dispose of them entirely. Do not put them in the compost pile, where spores could grow and spread.
Prevention
- Apply a preventative dose of fungicide as soon as blooms start to show color on the plant. The preventative can be applied as a soil drench or directly to the flowers on the plant.
- Avoid overhead watering during blooming.
- Remove any leaf litter and dead flowers at the end of the season.
- Cover the ground under infected plants with 4” of fresh organic mulch before winter, taking care not to disturb the infected soil.
- Buy bare-root specimens when available.
- When potted plants are purchased, remove the top layer of potting soil and replace it with fresh mulch.
- Plant cultivars that bloom early in the season before the temperatures get high enough for petal blight pathogens to be spreading.
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Underwatering
Leaves may wilt for a variety of reasons.
Overview
Underwatering plants is one of the quickest ways to kill them. This is something that most gardeners are well aware of. Unfortunately, knowing exactly how much water a plant needs can be tricky, especially considering that underwatering and overwatering present similar symptoms in plants.
Therefore, it’s important to be vigilant and attentive to each plants’ individual needs.
Symptom Analysis
As mentioned earlier, overwatering and underwatering present similar symptoms in plants. These symptoms include poor growth, wilted leaves, defoliation, and brown leaf tips or margins. Ultimately, both underwatering and overwatering can lead to the death of a plant.
The easiest way to determine whether a plant has too much water or too little is to look at the leaves. If underwatering is the culprit, the leaves will look brown and crunchy, while if it’s overwatering, they will appear yellow or a pale green in color.
When this issue first begins, there may be no noticeable symptoms at all, particularly in hardy or drought-tolerant plants. However, they will begin to wilt once they start suffering from a lack of water. The edges of the plant’s leaves will become brown or curled. Soil pulling away from the edges of the planter is a telltale sign, or a crispy, brittle stem.
Prolonged underwatering can cause a plant’s growth to become stunted. The leaves might drop and the plant can be more susceptible to pest infestations, too.
Disease Cause
Underwatering is caused by, quite simply, not watering plants often or deeply enough. There is a heightened risk of underwatering if any of these situations apply:
- Extreme heat and dry weather (when growing outdoors)
- Grow lights or indoor lighting that is too bright or intense for the type of plant
- Using fast-draining growing media such as sand
Solutions
The easiest (and most obvious) way to address underwatering is to fully hydrate the plant. However, this must be done carefully. A common mistake that many gardeners make is to douse their underwatered plants with water. This can overwhelm the roots of the plant and shock its system, something that can be even more damaging than the lack of water to begin with.
Instead, water thoroughly and slowly, taking breaks to let the water slowly saturate through the soil to get to the roots. Use room temperature water, as cold water might be too much of a shock.
In the future, shorten the time between waterings. A good rule of thumb is to check the soil around each plant daily. If it’s dry to at least two inches down, it’s time to water. If a container plant is repeatedly drying out very quickly, repotting into a slower-draining container might be a good idea, too.
Prevention
Always check the soil before watering. If the top inch of soil feels moist, though not wet, the watering is perfect. If it’s dry, water it immediately. If it feels soggy, you avoid watering until it dries out a bit more.
Also, make sure the lighting is sufficient for the species. Plants grow faster and need more water when there is intense light or lots of heat. Being aware of these conditions and modifying them, if possible, is a good way to prevent underwatering. Many container plants are potted in soil mixtures mean to be well-draining. Adding materials that retain moisture, like compost or peat moss, can also prevent these symptoms.
Other tips to prevent underwatering include:
- Choose pots with adequately-sized drainage holes
- Avoid warm temperatures
- Use large pots with additional soil (these take longer to dry out)
- Avoid terracotta pots, which lose water quickly
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Distribution Map
Habitat
Ditches, Pond verges, Lakesides, Marshes
Native
Cultivated
Invasive
Potentially invasive
Exotic
No species reported
More Info
Plant Type
Herb
Flower Color
Purple
Lavender
Bloom Time
Late spring, Summer, Fall
Leaf Color
Green
Purple
Name story
Mexican petunia
As a plant in the Ruellia genus, its flowers and very similar to petunia, and its height can reach about 91 cm. Hence, petunia appears as part of the name. As it is also native to Mexico, it is called Mexican petunia.
Symbolism
Resentment, Anger, Reconciliation, Your presence soothes me.
Usages
Garden Use
Mexican petunia is grown ornamentally often for its attractive lilac flowers. However, this plant is an aggressive grower so using a container to control growth is strongly advised. Other quick-growing flowers like butterfly weed and pale purple coneflower make good partners for mexican petunia. It is well suited to prairie, meadow, and rock gardens.
Scientific Classification
Phylum
Vascular plants Class
Dicotyledons Family
Acanthus Genus
Wild petunias Species
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Montbretia
Montbretia (Crocosmia crocosmiiflora) is a hybrid flowering plant native to France. The Latin name Crocosmia crocosmiiflora is derived from the Greek word "krokus" (saffron) and "osme" (smell). This plant's dried flowers smell of saffron when hot water is added to them.
Tievine
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The basket plant is a common houseplant. It doesn't require much light to grow. Its tiny flowers are white and have a pleasant scent. If grown in intense sunlight the leaves will often turn purplish.
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Man to man (Peperomia pellucida) is a perennial flowering plant that blooms all year. The entire man to man plant is edible and can be eaten raw or cooked.
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Add to My Garden Mexican petunia
Ruellia simplex
Also known as: Texas Petunia, Mexican blue bells, Britton's wild petunia
Twice per week
Water
Full sun
Sunlight
Care Guide for Mexican petunia
Water
Though Mexican petunia is drought tolerant, it still does best in soil that is consistently moist. Water about twice each week to keep the soil from drying out. However, the exact watering schedule will vary depending on the weather conditions. When transplanting or dealing with tender young plants, water Mexican petunia more often and deeply.
Fertilization
Mexican petunia doesn't require fertilizer but will enjoy the extra boost. Feed it with a tablespoon of 10-10-10 fertilizer occasionally throughout the flowering season.
Pruning
Trim the diseased, withered leaves once a month.
Soil
Loam
Potting Suggestions
Needs excellent drainage in pots.
Tips, advice, and instructions for over 13,000 species that you will find nowhere else
Mexican petunia
Ruellia simplex
Water
Twice per week
Sunlight
Full sun
Hardiness Zones
8 to 11
Planting Time
Spring, Summer
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Questions About Mexican petunia
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Common Pests & Diseases
Common issues for Mexican petunia based on 10 million real cases
Leaf beetles
Leaf beetles are a class of colored insects 1 to 2 cm in size. They gnaw on leaves and petals resulting in small, round holes scattered over the surface.
Solutions: For less serious cases: Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread. To treat more serious infestations: Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions. Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.
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Flower withering
Flowers may dry out due to a sudden change in environment or because the plant has completed its normal flowering period.
Solutions: If flower withering is a natural progression due to age, there is nothing that can be done to slow or stop the process. Once hormones within the plant begin the process of senescence, it’s irreversible. For lack of water, immediately water the plant using room temperature rainwater, bottled spring water, or filtered tap water. Water container plants until excess water drains out the bottom; water in-ground plants until the soil is soaked but there isn’t standing water on the surface. In the event of nutritional deficiencies, the best solution is to use a granular or water-soluble liquid fertilizer, and apply it to the soil at about half the recommended dosage. Keep it off the leaves and make sure granular products are watered into the soil well. If the plant is infected with a bacterial or fungal pathogen, there is no course of treatment that cures the diseased plants. The best solution is to remove the infected plants and dispose of the plant material off-site. Do not put in a compost pile.
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Caterpillars
Caterpillars are fleshy moth or butterfly larvae that come in an array of colors, patterns, and even hairstyles. They chew on leaves and flower petals, creating large, irregular holes.
Solutions: Even though caterpillars are diverse, they all chew on plant parts and can cause significant damage if present in large numbers. For severe cases: Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects. Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans. Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps. For less severe cases: Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water. Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.
Learn More ![more]()
Wilting after blooming
Flowers may wither for a variety of reasons.
Solutions: Check the soil or potting medium. Coarse textures can allow water to drain too rapidly, preventing the plant from taking up enough. If the soil and roots seem very dry, add sphagnum moss or other mediums that hold water. Water according to recommendations for each plant's species. Low humidity can be corrected by misting the plant regularly or placing it near a humidifier. Keeping it near other plants helps, too. Keep the environment consistent in terms of temperature, humidity, and lighting. Keep it away from vents, heaters, and air conditioners, and avoid moving it to locations where it will experience a temperature shock. Hot, dry heat, and cold drafts are problematic for many plants. Especially if the plant is outside, it could be experiencing heat or light stress. Try moving it to a shadier location.
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Petal blight
Bacterial infections can cause flowers to become soft and rotten.
Solutions: Like other fungal diseases, the progression of petal blight is extremely difficult to stop and impossible to reverse once it infects a plant. The best course of action is to remove all damaged flowers immediately and dispose of them entirely. Do not put them in the compost pile, where spores could grow and spread.
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Underwatering
Leaves may wilt for a variety of reasons.
Solutions: The easiest (and most obvious) way to address underwatering is to fully hydrate the plant. However, this must be done carefully. A common mistake that many gardeners make is to douse their underwatered plants with water. This can overwhelm the roots of the plant and shock its system, something that can be even more damaging than the lack of water to begin with. Instead, water thoroughly and slowly, taking breaks to let the water slowly saturate through the soil to get to the roots. Use room temperature water, as cold water might be too much of a shock. In the future, shorten the time between waterings. A good rule of thumb is to check the soil around each plant daily. If it’s dry to at least two inches down, it’s time to water. If a container plant is repeatedly drying out very quickly, repotting into a slower-draining container might be a good idea, too.
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Keep your leafy friends healthy and happy.
Diagnose your plant, and learn how to prevent and treat plant diseases.
Leaf beetles
Leaf beetles are a class of colored insects 1 to 2 cm in size. They gnaw on leaves and petals resulting in small, round holes scattered over the surface.
Overview
Leaf beetles range in size from 1.5 mm to 2 cm. Both adult beetles and their larvae eat the leaves of many different types of plants. There are over 35,000 different species of leaf beetles, in a variety of colors including gold, green, yellow-striped, and red striped. Some of these have been mistaken for ladybirds because of their shape and coloring. They can be oval, round, or elongated in shape. These insect pests are most active in spring and summer.
If not controlled, leaf beetles can do a lot of damage to vegetable crops and ornamental plants. They feed on the leaves, flowers, stems, roots, and fruits of different plants. They can fly, which means it's easy for them to move from one plant to another. Some species of leaf beetles only target one specific crop, while others will target many different types of plants. Although a lot of the damage that they cause is cosmetic, an infestation can weaken a plant and leave it prone to other more problematic diseases.
Symptom Analysis
The first signs of a leaf beetles infestation are small visible holes in leaves. Leaves then become discolored and dark beetle droppings can be seen. As the leaves turn yellow and brown, they will drop off the plant onto the ground. Some leaves will appear skeletonized with only the veins still remaining.
Infestation begins in spring, when the adult beetles emerge from the soil and lay their eggs on the leaves of plants. When these eggs hatch, the young nymphs start munching on the leaves as they grow up. Once leaf beetles are large and mature, they'll fall to the ground and pupate in the soil over winter before starting the cycle all over again.
Leaf beetles also eat holes in fruits and vegetables. These can be seen as small round holes that sometimes have a larger brown area surrounding them.
Solutions
For less serious cases:
- Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread.
To treat more serious infestations:
- Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions.
- Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.
Prevention
To prevent infestations of leaf beetles, follow these practices.
- Regularly check for beetles. To prevent large pest infestations, be proactive about frequently checking plants for pests and removing them quickly.
- Clear debris. Clear weeds and debris to remove areas where these beetles may overwinter and hide.
- Attract natural predators. Birds and other insects, such as wasps and ladybugs, are effective natural predators of leaf beetles. Encourage them to visit by including a diverse array of plants to provide habitat and food. Also, avoid applying broad-spectrum herbicides that can harm and kill beneficial insects.
- Plant aromatic herbs like mint, garlic, or rosemary, as these can repel leaf beetles.
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Flower withering
Flowers may dry out due to a sudden change in environment or because the plant has completed its normal flowering period.
Overview
Flower withering occurs when flowers become weak, droopy, wilted, or faded until they can’t be revived. During withering, they begin to wrinkle and shrink until the flower becomes completely dry or dead.
Any flowers, regardless of the plant type or the climate they are grown in, are susceptible to withering. It is a worldwide problem across houseplants, herbs, flowering ornamentals, trees, shrubs, garden vegetables, and food crops.
Unlike wilting—which withering is often confused with—withering can be caused by different things and is often due to more than a lack of water. Withering can be fatal in severe cases.
Symptom Analysis
Flower withering progresses from very mild cases to severe occurrences that kill the flower. The severity of the symptoms is related to the cause and how long the condition is allowed to progress before action is taken.
- Wilted, droopy flowers
- Petals and leaves begin to wrinkle
- Brown papery streaks or spots appear on the petals and leaf tips
- Flowerhead shrink in size
- Petal color fades
- Yellowing leaves
- Complete death of the flower
Disease Cause
The main causes of flower withering include natural age progress, lack of water, nutritional deficiencies, and bacterial or fungal diseases. It’s critical to determine the underlying cause when flower withering is noticed. This will guide the best course of action, if treatment is possible.
Check the soil for moisture and then closely examine the entire plant for signs of nutrient deficiencies. If neither of those appears to be the cause then cut open the stem below a flower. If a cross-section reveals brown or rust-colored stains it is safe to assume that this is a bacterial or fungal infection.
If the flower is nearing the end of its normal lifespan, genetic coding within the plant increases the production of ethylene, a phytohormone that controls senescence, or cell aging and death. Cell division stops and the plant begins breaking down resources within the flower to use in other parts of the plant.
In all other cases, flower withering happens when the plant seals off the stem as a defense mechanism, stopping transport within the vascular system. This prevents further water loss through the flowers but also stops bacteria and fungi from moving to healthy parts of the plant. Once water and nutrient transport stops, the flower begins to wither and ultimately die.
Solutions
If flower withering is a natural progression due to age, there is nothing that can be done to slow or stop the process. Once hormones within the plant begin the process of senescence, it’s irreversible.
For lack of water, immediately water the plant using room temperature rainwater, bottled spring water, or filtered tap water. Water container plants until excess water drains out the bottom; water in-ground plants until the soil is soaked but there isn’t standing water on the surface.
In the event of nutritional deficiencies, the best solution is to use a granular or water-soluble liquid fertilizer, and apply it to the soil at about half the recommended dosage. Keep it off the leaves and make sure granular products are watered into the soil well.
If the plant is infected with a bacterial or fungal pathogen, there is no course of treatment that cures the diseased plants. The best solution is to remove the infected plants and dispose of the plant material off-site. Do not put in a compost pile.
Prevention
This is definitely one of those instances where prevention is more effective than cure. Here are some preventative measures for avoiding premature flower withering.
- Water plants according to their needs -- either keep the soil slightly moist or allow the top inch or two to dry out before watering again.
- Fertilize lightly on a consistent basis, depending upon the plant’s growth. Quick-growing plants and those that flower or develop fruit will need more frequent fertilizing than slow-growing plants.
- Purchase plants that are certified disease- or pathogen-free.
- Look for disease-resistant cultivars.
- Isolate plants showing disease symptoms to prevent the spread to neighboring plants.
- Practice good plant hygiene by removing any fallen plant material as soon as possible.
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Caterpillars
Caterpillars are fleshy moth or butterfly larvae that come in an array of colors, patterns, and even hairstyles. They chew on leaves and flower petals, creating large, irregular holes.
Overview
Caterpillars can cause problems for home gardeners. If not managed, these insects can defoliate a plant in just a matter of days. However, home gardeners face a challenge because these caterpillars eventually turn into beautiful butterflies and moths, which are important for pollination and the general ecosystem.
There are thousands of different species of caterpillars and many will only target certain plants. If caterpillars are posing a problem, they can be removed by hand, or gardeners can use insect-proof netting to protect their valuable plants.
Symptom Analysis
Caterpillars are the larvae of butterflies and moths. During the warmer months, butterflies and moths that visit gardens will lay their eggs on the underside of leaves.
When the tiny eggs hatch, the young larvae emerge and start feeding on the leaves of the plant. Depending on how many larvae have hatched, they can easily defoliate the plant in a very short period of time. Caterpillars will shed their skin as they grow, around 4 or 5 times during this feeding cycle.
Symptoms of caterpillars eating plants appear as holes in the leaves. The edges of the leaves may be eaten away as well, and flowers can be affected as well.
Some are easy to see, but others need to be searched for. This is because their bodies are often camouflaged to look like part of the plant. Gardeners need to look carefully along the stems of the plant as well as under the leaves. Also, look for tiny white, yellow, or brown eggs that can be found in groups on the underside of leaves.
Once the caterpillar is fully grown, it transforms into a pupa or chrysalis. Then, after a period of time that varies according to the species, a butterfly or moth will emerge from the pupa and the cycle begins again.
Solutions
Even though caterpillars are diverse, they all chew on plant parts and can cause significant damage if present in large numbers.
For severe cases:
- Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects.
- Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans.
- Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps.
For less severe cases:
- Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water.
- Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.
Prevention
Prevention may require less effort than attempts to eradicate infestations that have already begun. Here are our top steps for prevention:
- Monitor plants. Check plants regularly for caterpillar eggs on leaves. If they do not belong to an endangered species, they should be squished.
- Use insect netting. Cover plants with insect netting to prevent butterflies and moths from laying eggs on plants.
- Apply diatomaceous earth. Apply DE to plants early in the season and reapply after rain.
- Encourage plant diversity. This will attract predatory insects including parasitic wasps.
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Wilting after blooming
Flowers may wither for a variety of reasons.
Overview
Wilting after blooming is sometimes a natural aging process of the flower, while other times it may indicate a problem. Orchids, for example, can bloom for anywhere from two weeks to three months, so wilting after a few days signals a problem for most varieties. This can happen to virtually any ornamental flowering plant, but those with shallow roots and limited tolerance for drought, full sun, and low humidity are more susceptible.
This is a common problem, and often has an easy fix. Sometimes, however, it is the result of more serious causes such as pests or disease of the root system.
Symptom Analysis
- At first, flowers may look a little limp.
- Petals may start to appear dried out and turn brown.
- Eventually they may drop off the plant all together.
Disease Cause
Wilting blooms can be a sign of an unhealthy root system. Any condition that prevents the plant from absorbing enough water and nutrition can result in wilting blooms and sometimes other symptoms. If the plant doesn’t have enough water, it cannot maintain appropriate pressure within stems, leaves, and blooms, causing them to wilt.
This can result from physical damage – for example from root breakage during re-potting or attack by insects like cutworms. If you recently re-potted your plant, physical damage to the roots is a likely cause. If you see insects, they may be eating leaves, roots, or flowers. Fungal infections can also cause root rot and damage, preventing water and nutrient uptake.
Finally, wilting blooms can result simply from age. If no other symptoms are visible, it may simply signal the natural end of the flower’s lifespan. If it seems premature, this may be caused by environmental factors: water, humidity, light, or stress. Under-watering is a common cause. Similarly, plants adapted to high humidity dry out easily when humidity is low, like during winter or in dry climates. Too much light can also stress plants that need shade, causing blooms to wilt.
Solutions
- Check the soil or potting medium. Coarse textures can allow water to drain too rapidly, preventing the plant from taking up enough. If the soil and roots seem very dry, add sphagnum moss or other mediums that hold water.
- Water according to recommendations for each plant's species.
- Low humidity can be corrected by misting the plant regularly or placing it near a humidifier. Keeping it near other plants helps, too.
- Keep the environment consistent in terms of temperature, humidity, and lighting. Keep it away from vents, heaters, and air conditioners, and avoid moving it to locations where it will experience a temperature shock. Hot, dry heat, and cold drafts are problematic for many plants.
- Especially if the plant is outside, it could be experiencing heat or light stress. Try moving it to a shadier location.
Prevention
- Read up on moisture, light, and soil type preferences for each plant to avoid underwatering, incorrect light levels, or other conditions that can cause wilting blooms.
- Avoid re-potting during the flowering period. This causes additional stress on the plants because they need to repair root damage and adapt to the new micro-environment, all of which can result in wilting.
- One other potential cause is ethylene gas, a plant hormone related to ripening. Some fruits and vegetables emit ethylene, especially bananas. Apples, grapes, melons, avocados, and potatoes can also give it off, so keep flowering plants away from fresh produce.
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Petal blight
Bacterial infections can cause flowers to become soft and rotten.
Overview
Petal blight, sometimes called flower blight, is a fungal disease that only affects the blooms of some ornamental flowering plants. As the infection progresses, it destroys the flower, yet it never damages the vegetative or green parts of the plant.
When flowers are infected, the symptoms look similar to Botrytis blight, but Botrytis also infects dead or dormant vegetative tissue.
The disease was first discovered in Japanese plants in 1919 and in the US in the late 1930s. Presently it is also found in New Zealand, Australia, and parts of Europe. Unfortunately, no plants have high resistance to petal blight, but specific cultivars are more susceptible than others, particularly species with double blooms.
Petal blight infection rates are high when temperatures are mild to warm (optimum temperatures are 15 to 21 ℃) and the weather is misty or rainy.
Overall, petal blight is an aesthetic problem that ruins blossoms. The disease is not harmful to the long-term health of the plant.
Symptom Analysis
The severity of the symptoms varies, depending upon the species of plant infected. Signs of petal blight are commonly seen on the blooms just after they open.
- Pallid spots on colored petals.
- Brown spots on white petals.
- Browning around the petal edges.
- Small spots look water-soaked.
- Spots rapidly enlarge and merge.
- Flowers become limp.
- The entire flower turns light brown, but does not crumble.
- Flowers become slimy at first and then take on a leathery texture.
- A ring of white or gray mycelium can be seen at the base of the petals.
Disease Cause
Petal blight is caused by several different fungi, with each type infecting specific plants. Ovulinia azalea infects azaleas species and cultivars, and rhododendrons. Ciborinia camelliae infects camellia cultivars.
Shortly after blooming, the fungus infects the base of the flowers by the calyx. The fungus produces cell wall-degrading enzymes that destroy flowers within a couple of days. When the flowers fall to the ground, the fungus' hard fruiting bodies fall to the soil as well, overwintering until the following spring.
When temperatures hit the optimum range the following season, spores are transmitted by insects or can spread on wind currents up to about 12 miles. Once in the soil, the pathogen can be active for three to five years.
Solutions
Like other fungal diseases, the progression of petal blight is extremely difficult to stop and impossible to reverse once it infects a plant. The best course of action is to remove all damaged flowers immediately and dispose of them entirely. Do not put them in the compost pile, where spores could grow and spread.
Prevention
- Apply a preventative dose of fungicide as soon as blooms start to show color on the plant. The preventative can be applied as a soil drench or directly to the flowers on the plant.
- Avoid overhead watering during blooming.
- Remove any leaf litter and dead flowers at the end of the season.
- Cover the ground under infected plants with 4” of fresh organic mulch before winter, taking care not to disturb the infected soil.
- Buy bare-root specimens when available.
- When potted plants are purchased, remove the top layer of potting soil and replace it with fresh mulch.
- Plant cultivars that bloom early in the season before the temperatures get high enough for petal blight pathogens to be spreading.
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Underwatering
Leaves may wilt for a variety of reasons.
Overview
Underwatering plants is one of the quickest ways to kill them. This is something that most gardeners are well aware of. Unfortunately, knowing exactly how much water a plant needs can be tricky, especially considering that underwatering and overwatering present similar symptoms in plants.
Therefore, it’s important to be vigilant and attentive to each plants’ individual needs.
Symptom Analysis
As mentioned earlier, overwatering and underwatering present similar symptoms in plants. These symptoms include poor growth, wilted leaves, defoliation, and brown leaf tips or margins. Ultimately, both underwatering and overwatering can lead to the death of a plant.
The easiest way to determine whether a plant has too much water or too little is to look at the leaves. If underwatering is the culprit, the leaves will look brown and crunchy, while if it’s overwatering, they will appear yellow or a pale green in color.
When this issue first begins, there may be no noticeable symptoms at all, particularly in hardy or drought-tolerant plants. However, they will begin to wilt once they start suffering from a lack of water. The edges of the plant’s leaves will become brown or curled. Soil pulling away from the edges of the planter is a telltale sign, or a crispy, brittle stem.
Prolonged underwatering can cause a plant’s growth to become stunted. The leaves might drop and the plant can be more susceptible to pest infestations, too.
Disease Cause
Underwatering is caused by, quite simply, not watering plants often or deeply enough. There is a heightened risk of underwatering if any of these situations apply:
- Extreme heat and dry weather (when growing outdoors)
- Grow lights or indoor lighting that is too bright or intense for the type of plant
- Using fast-draining growing media such as sand
Solutions
The easiest (and most obvious) way to address underwatering is to fully hydrate the plant. However, this must be done carefully. A common mistake that many gardeners make is to douse their underwatered plants with water. This can overwhelm the roots of the plant and shock its system, something that can be even more damaging than the lack of water to begin with.
Instead, water thoroughly and slowly, taking breaks to let the water slowly saturate through the soil to get to the roots. Use room temperature water, as cold water might be too much of a shock.
In the future, shorten the time between waterings. A good rule of thumb is to check the soil around each plant daily. If it’s dry to at least two inches down, it’s time to water. If a container plant is repeatedly drying out very quickly, repotting into a slower-draining container might be a good idea, too.
Prevention
Always check the soil before watering. If the top inch of soil feels moist, though not wet, the watering is perfect. If it’s dry, water it immediately. If it feels soggy, you avoid watering until it dries out a bit more.
Also, make sure the lighting is sufficient for the species. Plants grow faster and need more water when there is intense light or lots of heat. Being aware of these conditions and modifying them, if possible, is a good way to prevent underwatering. Many container plants are potted in soil mixtures mean to be well-draining. Adding materials that retain moisture, like compost or peat moss, can also prevent these symptoms.
Other tips to prevent underwatering include:
- Choose pots with adequately-sized drainage holes
- Avoid warm temperatures
- Use large pots with additional soil (these take longer to dry out)
- Avoid terracotta pots, which lose water quickly
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Distribution Map
Habitat
Ditches, Pond verges, Lakesides, Marshes
Map
Native
Cultivated
Invasive
Potentially invasive
Exotic
No species reported
More Info
Plant Type
Herb
Flower Color
Purple
Lavender
Bloom Time
Late spring, Summer, Fall
Leaf Color
Green
Purple
Name story
Mexican petunia
As a plant in the Ruellia genus, its flowers and very similar to petunia, and its height can reach about 91 cm. Hence, petunia appears as part of the name. As it is also native to Mexico, it is called Mexican petunia.
Symbolism
Resentment, Anger, Reconciliation, Your presence soothes me.
Usages
Garden Use
Mexican petunia is grown ornamentally often for its attractive lilac flowers. However, this plant is an aggressive grower so using a container to control growth is strongly advised. Other quick-growing flowers like butterfly weed and pale purple coneflower make good partners for mexican petunia. It is well suited to prairie, meadow, and rock gardens.
Scientific Classification
Phylum
Vascular plants Class
Dicotyledons Family
Acanthus Genus
Wild petunias Species
Mexican petunia Related Plants
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