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Add to My Garden Pygmy water lily
Nymphaea tetragona
Pygmy water lily is a hardy aquatic perennial that thrives in areas with ample sun but with cooler temperatures. This small, plant is typically used for still-water garden ponds and water features, providing a wonderful aesthetic while also offering shelter for aquatic creatures and controlling algae spread.
4 to 10
Hardiness Zones
Care Guide for Pygmy water lily
Soil
Loam, Clay, Sand, Chalky, Acidic
Sunlight
Full sun, Partial sun
Hardiness Zones
4 to 10
Planting Time
Late spring, Summer
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Pygmy water lily
Sunlight
Full sun
Hardiness Zones
4 to 10
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Pygmy water lily
Sunlight
Full sun
Hardiness Zones
4 to 10
Download
Pygmy water lily
Sunlight
Full sun
Hardiness Zones
4 to 10
Download
Questions About Pygmy water lily
Watering 
Pruning 
Sunlight 
Temperature 
Fertilizing What is the best way to water my Pygmy water lily?
When watering the Pygmy water lily, 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 Pygmy water lily 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 Pygmy water lily too much or too little?
Both overwatering and underwatering will be detrimental to the health of your Pygmy water lily, 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 Pygmy water lily, 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 Pygmy water lily have become brittle and brown.
It is crucial that you notice the signs of overwatering as soon as possible when caring for your Pygmy water lily. 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 Pygmy water lily 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 Pygmy water lily 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 Pygmy water lily?
If your plant is in a pot. The most precise way to decide whether your Pygmy water lily 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 Pygmy water lily 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 Pygmy water lily can show an admirable ability to withstand drought.
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How much water does my Pygmy water lily need?
When it comes time to water your Pygmy water lily, 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 Pygmy water lily at different growth stages?
The water needs of the Pygmy water lily can change depending on growth stages as well. For example, when your Pygmy water lily 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 Pygmy water lily 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 Pygmy water lily 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 Pygmy water lily more water at this time.
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How should I water my Pygmy water lily through the seasons?
The Pygmy water lily 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 Pygmy water lily will contract a disease.
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What's the difference between watering my Pygmy water lily indoors and outdoors?
It is most common to grow the Pygmy water lily 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 Pygmy water lily 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 Pygmy water lily 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 Pygmy water lily based on 10 million real cases
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.
Black spot
Infection by the black spot pathogen causes black spots or patches to appear on leaves.
Solutions: Some steps to take to address black spot include: Prune away any infected leaves, cleaning the pruners between plants with a 10% bleach solution so that the fungus does not spread to healthy leaves. Don't compost pruned plant parts as the spores can linger in the soil for a long period of time - instead, dispose of them in the trash. Use an approved fungicide such as Trifloxystrobin, Chlorothalonil, Maneb, or Myclobutanil. Use a spreader in the fungicide spray to ensure better coverage.
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.
Keep your leafy friends healthy and happy.
Diagnose your plant, and learn how to prevent and treat plant diseases.
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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Black spot
Infection by the black spot pathogen causes black spots or patches to appear on leaves.
Overview
Black spot is a fungus that largely attacks leaves on a variety of ornamental plants, leaving them covered in dark spots ringed with yellow, and eventually killing them. The fungus is often simply unsightly, but if it infects the whole plant it can interfere with photosynthesis by killing too many leaves. Because of this, it is important to be aware of the best methods for preventing and treating this diseases should it occur in the garden.
Symptom Analysis
Here are a few of the most common symptoms of black spot:
- The plant has developed small black spots along the leaves.
- These spots be small, circular, and clustered together, or they may have a splotchy appearance and take up large portions of the leaves.
- The fungus may also affect plant canes, where lesions start purple and then turn black.
- The plant may suffer premature leaf drop.
Though most forms of black spot fungus pose little risk to a plant's overall health, many gardeners find them unsightly. Severe cases can also weaken a plant, so it becomes more susceptible to other pathogens and diseases.
Disease Cause
Black spot is spread by various types of fungi, which differ slightly depending on whether they are in their sexual or asexual stages.
The fungal spores linger over the winter in fallen leaves and lesions on canes. In the spring, the spores are splashed up onto the leaves, causing infection within seven hours of moisture and when temperatures range between 24 to 29 ℃ with a high relative humidity.
In just two weeks, thousands of additional spores are produced, making it easy for the disease to infect nearby healthy plants as well.
There are several factors that could make a plant more likely to suffer a black spot infection. Here are some of the most common:
- Exposure to infected plants or mulch (the fungus overwinters on dead leaves)
- Weakening from physical damage, pest infestation or other infections.
- Increased periods of wet, humid, warm weather – or exposure to overhead watering
- Plants growing too close together
Solutions
Some steps to take to address black spot include:
- Prune away any infected leaves, cleaning the pruners between plants with a 10% bleach solution so that the fungus does not spread to healthy leaves.
- Don't compost pruned plant parts as the spores can linger in the soil for a long period of time - instead, dispose of them in the trash.
- Use an approved fungicide such as Trifloxystrobin, Chlorothalonil, Maneb, or Myclobutanil.
- Use a spreader in the fungicide spray to ensure better coverage.
Prevention
Here are a few tips to prevent black spot outbreaks.
- Purchase resistant varieties: Invest in fungus-resistant plant varieties to reduce the chances for black spot diseases.
- Remove infected plant debris: Fungi can overwinter in contaminated plant debris, so remove all fallen leaves from infected plants as soon as possible.
- Rake and discard fallen leaves in the fall.
- Prune regularly.
- Water carefully: Fungal diseases spread when plants stay in moist conditions and when water droplets splash contaminated soil on plant leaves. Control these factors by only watering infected plants when the top few inches of soil are dry, and by watering at soil level to reduce splashback. Adding a layer of mulch to the soil will also reduce splashing.
- Grow plants in an open, sunny locations so the foliage dries quickly.
- Follow spacing guidelines when planting and avoid natural windbreaks for good air circulation.
- Use chemical control: Regular doses of a fungicide, especially in the spring, can stop an outbreak before it begins.
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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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Distribution Map
Habitat
Ponds, shallow lakes, ponds, lakes, quiet streams
Native
Cultivated
Invasive
Potentially invasive
Exotic
No species reported
More Info
Plant Type
Herb
Flower Color
White
Pink
Purple
Scientific Classification
Phylum
Vascular plants Class
Dicotyledons Family
Water-lily Genus
Water lilies Species
Pygmy water lily Related Plants
Rainbow tree
The rainbow tree (Dracaena angustifolia) is native to Asia and is a member of the asparagus family that grows in the understories of tropical forests. Ornamentally, it can function both as an indoor and outdoor shrub. Substances from the rainbow tree can be used to create green dye.
Bloom Time
Summer
Garden Usage
Dracaena plants of Asparagaceae (Dracaena spp.) are excellent indoor ornamental plants, easy to maintain. They can be evergreen and grow slowly with a continuous water supply and proper filtered light ensured. The leaves of corn plants are often used to decorate flower bouquets; the lucky bamboo can be used for decoration as a hydroponic plant, and the gold dust can be planted outdoors as bushes.
Indian banyan
Indian banyan (Ficus benghalensis) is a tree species that germinates in cracks and crevices of other trees or structures. Indian banyan grows by emitting aerial roots and forming a canopy. The indian banyan is the national tree of the Republic of India and has religious significance.
Bloom Time
All year around
Garden Usage
Plants of genus Ficus are often used in arbors and shrubs, as it usually grows large. If it is planted in a garden, choose a wide plot to give it enough space. It can also be planted in a flowerpot and maintained indoors at early stages, and transplanted to a garden later on. Its attractive green leaves require a warm, humid environment; we consider it a medium level difficulty plant to care.
Pinwheel flower
Pinwheel flower (Tabernaemontana divaricata) is an evergreen shrub that can grow to 2.5 m tall. White, pinwheel-shaped flowers with a carnation-like fragrance bloom year-round. Easy to grow in light shade to full sun. Popular as a backdrop for gardens and as a natural hedge.
Bloom Time
Spring, summer
Common globe amaranth
Common globe amaranth (Gomphrena globosa) is an edible flowering plant native to Central America. Other common names for common globe amaranth are the makhmali and vadamalli. Common globe amaranth is commonly cultivated in landscaping for its bright colors, and is used in leis in Hawaii. Common globe amaranth attracts insects, including butterflies and bees.
Bloom Time
Summer, autumn
Garden Usage
The common globe amaranth is commonly planted at the front of borders, where it fills in any gaps left behind by spring bulbs. However, newly-bred varieties have given gardeners more options, with this plant now being used more creatively. No matter the variety you choose, the common globe amaranth is a strong and resilient plant that is extremely easy to care for and requires little maintenance once established., The common globe amaranth produces colorful flowers in purples, whites, and oranges, with all varieties having a long blooming time. In addition to brightening up the garden, these gorgeous blooms are also popular cut flowers, and last for several years when used in dried flower arrangements.
Mistletoe cactus
Mistletoe cactus (Rhipsalis baccifera) is a species found in Central America, South America, the Caribbean, and Florida. Mistletoe cactus is the only cactus species that occurs naturally outside the New World. It is hypothesized that it was seeded in Africa by migratory birds traveling across the Atlantic Ocean. This species is considered easy to maintain as a houseplant and is often grown as a houseplant in hanging planters.
Bloom Time
All year around
Garden Usage
Cactus are popular choices to plant in pots or in gardens for ornamental effect. They often have succulent stems, are commonly covered with thorns, and give delicate flowers. Most plants of Cactaceae family are resistant to drought, need sufficient sunlight, and are easy to care for.
Cape marguerite
Osteospermum ecklonis, commonly known as cape marguerite, is an evergreen, perennial small shrub with typical daisy-shaped white or purple flowers. It is cultivated as an ornamental in containers and borders. Flowers of this lovely plant are often visited by bees and other pollinators.
Bloom Time
Summer, autumn
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Add to My Garden Pygmy water lily
Nymphaea tetragona
4 to 10
Hardiness Zones
Care Guide for Pygmy water lily
Soil
Loam, Clay, Sand, Chalky, Acidic
Sunlight
Full sun, Partial sun
Hardiness Zones
4 to 10
Planting Time
Late spring, Summer
Tips, advice, and instructions for over 13,000 species that you will find nowhere else
Pygmy water lily
Nymphaea tetragona
Sunlight
Full sun
Hardiness Zones
4 to 10
Download
Questions About Pygmy water lily
Watering Pruning Sunlight Temperature Fertilizing What is the best way to water my Pygmy water lily?
Free
What should I do if I water my Pygmy water lily too much or too little?
Free
How often should I water my Pygmy water lily?
Free
How much water does my Pygmy water lily need?
How should I water my Pygmy water lily at different growth stages?
Show More ![more]()
You’ve got questions. We’ve got answers.
Let us help take all the guesswork out of your gardening.
More Questions People Also Ask
Common Pests & Diseases
Common issues for Pygmy water lily based on 10 million real cases
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.
Learn More ![more]()
Black spot
Infection by the black spot pathogen causes black spots or patches to appear on leaves.
Solutions: Some steps to take to address black spot include: Prune away any infected leaves, cleaning the pruners between plants with a 10% bleach solution so that the fungus does not spread to healthy leaves. Don't compost pruned plant parts as the spores can linger in the soil for a long period of time - instead, dispose of them in the trash. Use an approved fungicide such as Trifloxystrobin, Chlorothalonil, Maneb, or Myclobutanil. Use a spreader in the fungicide spray to ensure better coverage.
Learn More ![more]()
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]()
Keep your leafy friends healthy and happy.
Diagnose your plant, and learn how to prevent and treat plant diseases.
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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Black spot
Infection by the black spot pathogen causes black spots or patches to appear on leaves.
Overview
Black spot is a fungus that largely attacks leaves on a variety of ornamental plants, leaving them covered in dark spots ringed with yellow, and eventually killing them. The fungus is often simply unsightly, but if it infects the whole plant it can interfere with photosynthesis by killing too many leaves. Because of this, it is important to be aware of the best methods for preventing and treating this diseases should it occur in the garden.
Symptom Analysis
Here are a few of the most common symptoms of black spot:
- The plant has developed small black spots along the leaves.
- These spots be small, circular, and clustered together, or they may have a splotchy appearance and take up large portions of the leaves.
- The fungus may also affect plant canes, where lesions start purple and then turn black.
- The plant may suffer premature leaf drop.
Though most forms of black spot fungus pose little risk to a plant's overall health, many gardeners find them unsightly. Severe cases can also weaken a plant, so it becomes more susceptible to other pathogens and diseases.
Disease Cause
Black spot is spread by various types of fungi, which differ slightly depending on whether they are in their sexual or asexual stages.
The fungal spores linger over the winter in fallen leaves and lesions on canes. In the spring, the spores are splashed up onto the leaves, causing infection within seven hours of moisture and when temperatures range between 24 to 29 ℃ with a high relative humidity.
In just two weeks, thousands of additional spores are produced, making it easy for the disease to infect nearby healthy plants as well.
There are several factors that could make a plant more likely to suffer a black spot infection. Here are some of the most common:
- Exposure to infected plants or mulch (the fungus overwinters on dead leaves)
- Weakening from physical damage, pest infestation or other infections.
- Increased periods of wet, humid, warm weather – or exposure to overhead watering
- Plants growing too close together
Solutions
Some steps to take to address black spot include:
- Prune away any infected leaves, cleaning the pruners between plants with a 10% bleach solution so that the fungus does not spread to healthy leaves.
- Don't compost pruned plant parts as the spores can linger in the soil for a long period of time - instead, dispose of them in the trash.
- Use an approved fungicide such as Trifloxystrobin, Chlorothalonil, Maneb, or Myclobutanil.
- Use a spreader in the fungicide spray to ensure better coverage.
Prevention
Here are a few tips to prevent black spot outbreaks.
- Purchase resistant varieties: Invest in fungus-resistant plant varieties to reduce the chances for black spot diseases.
- Remove infected plant debris: Fungi can overwinter in contaminated plant debris, so remove all fallen leaves from infected plants as soon as possible.
- Rake and discard fallen leaves in the fall.
- Prune regularly.
- Water carefully: Fungal diseases spread when plants stay in moist conditions and when water droplets splash contaminated soil on plant leaves. Control these factors by only watering infected plants when the top few inches of soil are dry, and by watering at soil level to reduce splashback. Adding a layer of mulch to the soil will also reduce splashing.
- Grow plants in an open, sunny locations so the foliage dries quickly.
- Follow spacing guidelines when planting and avoid natural windbreaks for good air circulation.
- Use chemical control: Regular doses of a fungicide, especially in the spring, can stop an outbreak before it begins.
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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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Distribution Map
Habitat
Ponds, shallow lakes, ponds, lakes, quiet streams
Map
Native
Cultivated
Invasive
Potentially invasive
Exotic
No species reported
More Info
Plant Type
Herb
Flower Color
White
Pink
Purple
Scientific Classification
Phylum
Vascular plants Class
Dicotyledons Family
Water-lily Genus
Water lilies Species
Pygmy water lily Related Plants
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