Cornflower (Centaurea cyanus) Flower, Leaf, Care, Uses

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Plant Encyclopedia > Cornflower

Cornflower

Centaurea cyanus

Also known as : Garden cornflower, Bluebottle

Centaurea cyanus is known by several names, like cornflower and bachelor’s button. This flower has a beautiful blue color that was a favorite of famed Dutch painter Johannes Vermeer. Today it is a Crayola crayon color as well as an HTML color name. The color is defined as a medium to light blue that contains very little green.

Water

Every week

Sunlight

Full sun

Care Guide for Cornflower

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Watering Care

Cornflower should be given about one inch of water per week when new plants are getting established, and during any extended hot or dry periods. Once established, though, they are drought-tolerant and should need little supplemental watering, unless you live in a very arid climate. That being said, extra water does help produce bigger, healthier blooms 鈥?just be sure not to oversaturate the soil.

Details on Watering Care

Fertilizing Care

Cornflower doesn't need rich soil to thrive, but does prefer growing in slightly alkaline soils. If your soil is already decent, you should need no supplemental fertilizer. If your soil is very poor or on the acidic side, you can add a fertilizer mix that boosts alkalinity. A small amount of crushed limestone sprinked around these plants can also help raise pH.

Details on Fertilizing Care

Pruning

Trim the diseased, withered leaves once a month.

Details on Pruning

Soil Care

Sand, Loam, Clay, Chalky, Acidic, Neutral, Alkaline

Details on Soil Care

Repotting

Needs excellent drainage in pots.

Details on Repotting

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Cornflower

Water

Every week

Sunlight

Full sun

Hardiness Zones

4 to 8

Planting Time

Mid spring, Late spring, Early summer

Questions About Cornflower

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Watering

Pruning

Sunlight

Temperature

Fertilizing

What is the best way to water my Cornflower?

To water Cornflower, you can use a garden hose with a spray nozzle, a watering can, or just about any other common watering tool. Generally, Cornflower is not too picky about how they receive their water, as they can live off of rainwater, tap water, or filtered water. Often, you should try not to water this plant from overhead, as doing so can damage the leaves and flowers and may lead to disease as well. At times, the best method for watering this plant is to set up a drip irrigation system. These systems work well for Cornflower as they apply water evenly and directly to the soil. For one Cornflower that grows in a container, you can use a similar watering approach while changing the tools you use. To water a container-grown Cornflower, use a cup, watering can, or your tap to apply water directly to the soil.

What should I do if I water my Cornflower too much or too little?

The remedy for underwatering Cornflower is somewhat obvious. When you notice that your plant lacks moisture, simply begin watering it on a more regular basis. The issue of overwatering can be a much more dire situation, especially if you fail to notice it early. When your Cornflower is overwatered, it may contract diseases that lead to its decline and death. The best way to prevent this outcome is to choose a proper growing location, one that receives plenty of sunlight to help dry the soil and has good enough drainage to allow excess water to drain rather than pooling and causing waterlogged soils. If you overwater your Cornflower that lives in a pot, you may need to consider changing it to a new pot. Your previous container may not have contained soil with good drainage or may not have had sufficient drainage holes. As you repot your overwatered Cornflower, make sure to add loose soils and to use a pot that drains efficiently.

How often should I water my Cornflower?

Cornflower needs water regularly throughout the growing season. Beginning in spring, you should plan to water this plant about once per week. As the season presses on and grows warmer, you may need to increase your watering rate to about two to three times per week. Exceeding at this rate can be detrimental to your Cornflower. With that said, you should also ensure that the soil in which your Cornflower grows remains relatively moist but not wet, regardless of how often you must water to make that the case. Watering Cornflower that lives in a pot is a bit different. Generally, you'll need to increase your watering frequency, as the soil in a pot can heat up and dry out a bit faster than ground soil. As such, you should plan to water a container-grown Cornflower a few times per week in most cases, versus just once per week for an in-ground plant.

How much water does my Cornflower need?

There are a few different ways you can go about determining how much water to give to your Cornflower. Some gardeners choose to pick their water volume based on feeling the soil for moisture. That method suggests that you should water until you feel that the first six inches of soil have become moist. Alternatively, you can use a set measurement to determine how much to water your Cornflower. Typically, you should give your Cornflower about two gallons of water per week, depending on how hot it is and how quickly the soil becomes dry. However, following strict guidelines like that can lead to overwatering if your plant requires less than two gallons per week for whatever reason. When growing Cornflower in a container, you will need to use a different method to determine how much water to supply. Typically, you should give enough water to moisten all of the layers of soil that have become dry. To test if that is the case, you can simply stick your finger in the soil to feel for moisture. You can also water the soil until you notice a slight trickle of excess water exiting the drainage holes of your pot.

How can I tell if i'm watering my Cornflower enough?

It can be somewhat difficult to avoid overwatering your Cornflower. On the one hand, these plants have relatively deep roots that require you to moisten the soil weekly. On the other hand, Cornflower are plants that are incredibly susceptible to root rot. Along with root rot, your Cornflower may also experience browning as a result of overwatering. Underwatering is far less likely for your Cornflower as these plants can survive for a while in the absence of supplemental watering. However, if you go too long without giving this plant water, it will likely begin to wilt. You may also notice dry leaves.

How should I water my Cornflower through the seasons?

You can expect your Cornflower’s water needs to increase as the season moves on. During spring, you should water about once per week. Then, as the summer heat arrives, you will likely need to give a bit more water to your Cornflower, at times increasing to about three times per week. This is especially true of Cornflower that grow in containers, as the soil in a container is far more likely to dry out faster than ground soil when the weather is warm. In autumn, while your Cornflower is still in bloom, it may need a bit less water as the temperature has likely declined, and the sun is no longer as strong as it was in summer.

How should I water my Cornflower at different growth stages?

Cornflower will move through several different growth stages throughout the year, some of which may require more water than others. For example, you will probably start your Cornflower as a seed. While the seed germinates, you should plant to give more water than your Cornflower will need later in life, watering often enough to maintain consistent soil moisture. After a few weeks, your Cornflower will grow above the soil and may need slightly less water than at the seedling phase. Then, once this plant is mature, you can begin to use the regular watering frequency of about once per week. As flower development takes place, you may need to give slightly more water to aid the process.

What's the difference between watering Cornflower indoors and outdoors?

There are several reasons why most Cornflower grow outdoors rather than indoors. The first is that these plants typically grow to tall. The second reason is that Cornflower needs more daily sunlight than most indoor growing locations can provide. If you are able to provide a suitable indoor growing location, you may find that you need to give your Cornflower water a bit more often than you would in an outdoor growing location. Part of the reason for this is that indoor growing locations tend to be a lot drier than outdoor ones due to HVAC units. The other reason for this is that soil in containers can dry out relatively quickly as well compared to soil in the ground.

Is pruning necessary for my Cornflower?

Cornflower is a kind of annual plant so it doesn't need much pruning. You only need to cut off and clean the diseased, yellow or dropped leaves and stems during its growing period. This will help your Cornflower to stay away from pathogens infection.

How do I prune my Cornflower?

During the growth of the plant, yellowing, drying and spotted leaves are produced, and these spotted and discolored leaves need to be trimmed off. If the whole piece of leave is discolored or infected, you will need to cut it off completely. In other situations, you will only need to cut off the discolored or infected part on certain leaves. Cornflower above the ground will die and dry up in the winter, and the dead plants need to be cleaned up.

Are there any cautions I should be careful with when pruning my Cornflower?

Cornflower leaves are delicate, so take care not to score or bruise them. Unless the leaves are withered or heavily discolored, do not prune the leaves from the lowermost branches unless they’re damaged. They typically grow the largest, so they supply the plant with critical energy to keep it growing right. Please prevent the wounds from water after pruning until they are fully recovered. Remember always sterilize the tools before pruning. When the pruning is finished, please throw all the waste leaves and stems into the trashbins to avoid diseases and bugs.

Are there any tips for pruning my Cornflower?

Sterilize all the tools before pruning; unclean tools will pass pathogens to the plant through wounds; Prune on sunny days because the new cuts will be infected by pathogens if they're distained by rain or water. Throw all the waste leaves and stems into trashbins, they will easily rot and attract diseases and bugs

When should/shouldn't I prune my Cornflower?

Expect to prune your Cornflower every week if it’s growing well or every two weeks if it grows slowly. It is always good to prune it on sunny days because if you prune it on rainy days, the rainwater will distain the cuts and cause the whole plant to be infected.

What should I look for when pruning my Cornflower in different seasons?

Because Cornflower is an annual plant, the pruning should take place basically during the seasons that the plant grows rapidly. During the growth of the plant, yellowing, drying and spotted leaves are produced, and these spotted and discolored leaves need to be trimmed off.

How much sunlight should Cornflower get per day to grow healthily?

You must expose the plants to at least 6 to 8 hours of sunlight daily. They prefer more exposure to the morning light, especially in the summer. The Cornflower needs full sun and more sunlight that it can get. The more light these species get, the more they can manufacture food, produce beautiful blooms, and survive.

What type of sunlight does Cornflower need?

The Cornflower grows best under full sunlight. It's best not to crowd them together so they can get exposure to the sun evenly. The leaves shouldn't be starved with sunlight. If planted in pots, try to expose the herbaceous flowers in windows with direct sun and ensure they receive full sunlight regardless of the months. They don't tend to do well in partial or filtered light as this will not produce strong stems and healthy flowers. It's best if the Cornflower is always exposed to the sun.

Can sunlight hurt plants? How to protect Cornflower from sun and heat damage?

When the temperature rises above 90℉(32℃), the Cornflower can get damaged by extreme temperatures, especially if they are exposed to many hours of sun. It's always ideal for providing some shade from the light in the afternoon in the summer. It's always important to keep in mind that the sunlight in the summer is stronger than the one in the winter. Sunlight exposure is also 50% longer in the summer than in the winter. If the Cornflower is too stressed with sunlight, you might want to keep them fully hydrated. Water them when the top of the soil is about 2 inches dry, and move the plants indoors if it's too hot outside. This is the case if they are planted in containers. It can be normal for the plant leaves to wilt during the day. Generally, they can recover at night. However, when you notice that the Cornflower is still drooping, this means that the plant is losing water fast, and you need to water them.

Should I protect Cornflower from sun exposure?

The Cornflower does not need any protection from the sun. In fact, they love the sun, and some species are heliotropic. Plant them in south-facing gardens whenever possible so they can be exposed from morning to afternoon. While the sun can benefit them, some may experience a sunburn. You might offer protection from the afternoon and midday sun through a shade of a tree or a wall. Growing the Cornflower in shady areas is impossible because the larger flowers would require a lot of energy to grow and produce. Always provide the lighting conditions and set them in an area with full sun for best results.

What will happen if Cornflower gets inadequate sunlight?

When the Cornflower does not get adequate sunlight, or they are not placed in full sun locations, it's worth noting that the photosynthetic process will slow down. A lack of sunlight will cause the stems to become more leggy since they become thin and long since they tend to seek too much sunlight. They will not bloom and produce seeds in the shade. Inadequate sunlight will also mean that the older leaves can die, the color of the new ones is lighter than the old foliage, and the new growth is smaller than the last ones. The Cornflower indeed loves the sun so much. However, they can wilt when exposed to excessive heat and ultraviolet light during the extreme summer months, so be careful. You might want to cover them with a net that has a green shade, especially in the summer, to prevent the leaves and the flowers from scorching. When they are indoors, reduce the heat with the help of a fan.

Does Cornflower need special care about sunlight during its different growth stages?

When the Cornflower is growing, they need more light than their mature counterparts. The younger ones should receive adequate light, but they might not be prepared for sudden full sunlight, especially if they are grown in a nursery. They can be more sensitive to the summer sun, so the lighting should be gradual and slow.

How much light does Cornflower need for photosynthesis?

During summer or late spring, the Cornflower needs 6 to 8 hours of direct light every single day. This is whether they are planted outdoors. If the Cornflower is planted in pots or you're growing them in the winter, they need direct fluorescent lights that help them grow better. Make sure to place them in an indoor area where they are facing south or east so they can have enough sunlight for photosynthesis.

Are there any cautions or tips for sunlight and Cornflower?

When transplanting the plants, they should not be exposed to sudden sunlight. Give the Cornflower to grow and mature before transplanting outside. Some species of herbaceous plants can grow taller and might cast a shade on other young plants. Allow between 80 to 100 days of growing season before planting another batch to ensure that every plant receives more than enough sunlight for at least 6 hours a day. Make sure that the Cornflower receives the best light possible, especially if it's planted in a nursery. These are sun-loving plants, but too much sunlight with a very hot temperature is also detrimental to their growth. Indoor lights should be replaced with natural sunlight as much as possible since these species crave this every day.

What is the optimal temperature for Cornflower?

The best temperature for Cornflower depends on the time of year. There are two primary seasons to discuss for temperature: the growing season, and the dormancy season. During the growing season, once Cornflower has begun to sprout, the ideal temperature range should be anywhere from 65~80℉(18~27℃). Any colder than 15℉(-10℃), and the plant will suffer; its leaves may brown and wilt, but if this is a short cold snap, then Cornflower may be able to survive with some help. During the warmer parts of the year, Cornflower will need to be similarly protected from temperatures that are too high. 95-105℉ (35-40℃) is the top of this plant’s temperature range, and anything above that will compromise the integrity of the foliage and blooms of Cornflower. Hotter temperatures can cause wilting, drooping, and even sunburn on the leaves, which can be difficult for Cornflower to recover from. There are quite a few ways to combat this issue that are quick and easy!

Temperature requirements for first year or seedling Cornflower

If this is the first year of your Cornflower outside as a new plant, then it may need a little extra tending during the coldest months of the year. Not only can frost more severely damage a first-year Cornflower, but it can also prevent it from growing back as a healthy plant come spring. This plant needs to be kept at 40℉(5℃) or above when they’re not yet established, which can be done either by bringing your Cornflower inside for a month or two, or putting up mulch or fabric barriers that protect from frost damage. It’s also a good idea to plant Cornflower in a shadier spot during the first year or two, as smaller and weaker plants have a more difficult time maintaining their own temperatures in the heat. First-year Cornflower should receive no more than five hours of direct sunlight per day, particularly if the ambient daytime temperature gets above 80℉(27℃). Shadecloth and frequent watering or misting are the keys to summer heat control.

How can I protect Cornflower from extreme temperatures?

If cold temperatures (below 15℉(-10℃)) do occur during the growing season, there are a few measures you can take to help protect Cornflower from frost or cold damage. If you’re growing Cornflower in a container, then the container can simply be brought inside in bright, indirect light until the temperatures rise up over the lower threshold again. Another option that’s better suited for ground-planted Cornflower is to use mulch or horticultural fabric to create an insulated barrier around the plant, which will protect the plant from frost and cold wind. For temperatures that are hotter than 80℉(27℃) in the shade during the day, be careful to only expose Cornflower to six hours or less of sunlight per day, preferably in the morning hours. Putting up shade cloth, or a fine plastic mesh, can help reduce the amount of direct sunlight that hits the plant during the hottest parts of the day. You can also install a misting system that allows for a slow release of cooling mist around the base of the plant during the day to lower ground temperatures.

Dormant season temperature recommendations for Cornflower

During the cold winter months, Cornflower needs a certain measure of cold in order to stay in dormancy until it’s time to sprout. Sprouting too early, that is before the danger of the last frost has passed, can be fatal to Cornflower, especially if it’s already had a head start when the frost hits. Winter temperatures should ideally stay below 32℉(0℃), but if they get up to 40℉(5℃), everything will be just fine. An unexpected warm spell during the cold months, which can happen in more temperate climates like woodland rainforests, can trigger a premature sprout from Cornflower. In this case, if there’s still imminent danger of frost, you may want to try covering it with clear plastic on stakes so that the cold has less of a chance of damaging the new sprout. This setup can be removed when the danger of frost has passed. Occasionally, Cornflower will be able to resprout at the correct time without any help, but this method increases the chances of a successful second sprouting.

Why do I need to fertilize my Cornflower?

Plants need nutrients to survive; most gardeners, regardless of experience, are well aware of this factor. However, without food, Cornflower will die out soon after the first pollination. Therefore, providing the right type of nutrients in the right amounts is the best way to keep Cornflower going throughout the blooming season and producing large, beautiful flowers. Fertilizer also helps Cornflower build a large, healthy root system. This plant needs all the help it can get since its root system is very thin and easily damaged. Fertilizing at planting helps Cornflower build a solid root structure that not only provides stability to the plant, but also sets the stage for a sensational flowering performance. When timed correctly, fertilization can greatly extend Cornflower's flowering period.

When is the best time to fertilize my Cornflower?

Cornflower puts on tremendous growth early in the growing season, once the danger of the last frost has passed. It’s during this time that Cornflower should be fertilized; more specifically, during planting. The idea is to apply when the plant is first planted in the ground or in planters; however you choose to plant it. This will be the only dose of fertilizer until later in the year, when blooms are in full force. Once the season is in full swing and Cornflower has opened most of its blooms at full size, it’s time to start fertilizing again. Around the time when blooms are at peak output, begin fertilizing again once every three to four weeks, as weather permits. Then, after Cornflower starts to put out fewer new blooms, stop fertilizing; there’s no need to fertilize when the plant can’t produce any more blooms.

When should I avoid fertilizing my Cornflower?

While regular fertilizing is important for Cornflower, it absolutely can be applied at the wrong time. Some situations call for holding back the fertilizer once in a while. These are usually climate related, but they also include a variety of controllable factors. Essentially, when something is wrong with the plant, the soil, or the climate, wait it out until things have been smoothed over and the plant has recovered. An example of when not to fertilize is if there are severe or unexpected changes in the weather. If a cold nap suddenly comes in the middle of summer, wait until it’s warm again to start fertilizing. The same stands for if the soil becomes too dry or too packed to absorb anything. At this point, fertilizer will be going straight to the roots, rather than being diffused by soil before it reaches them. As you can imagine, the roots of Cornflower aren’t very fond of that. When temperatures soar during the hottest parts of the day into the 90-degree fahrenheit range, don’t apply fertilizer. Since fertilizer can be broken down at various speeds depending on temperature, it’s especially important not to allow hot temperatures to break it down too quickly. Pests or diseases should also be treated and cleared up before re-fertilizing.

What type of fertilizer does my Cornflower need?

Most types of Cornflower need the same general balance of nutrients from fertilizer. These should come in the form of a fertilizer that’s formulated specifically for high-yield blooming plants. A fertilizer with a higher level of phosphorus is the best option. This type of fertilizer has a higher P number in its NPK number, for example 10-30-10. Several fertilizer brands sell a fertilizer that’s perfect for blooming plants like Cornflower, which are an easy and fuss-free way to provide the right nutrients. If you do choose to use a pre-mixed fertilizer, follow the directions on the package to prevent Cornflower from getting too much or too little fertilizer, both of which can cause the plant to grow poorly or even wilt entirely.

How do I fertilize my Cornflower?

Depending on the type of fertilizer you have, specific fertilizing instructions may vary. However, there are a few general tips for applying most types of fertilizer to Cornflower. The first fertilizer application, which should be when you first plant Cornflower, will likely consist of mixing the recommended amount of fertilizer into the soil before planting and watering in the Cornflower. Subsequent fertilizing may look a little different. For pellet fertilizers, simply mix the pellets into the top inch of soil around the outer edge of the plant, where the roots are. Water them in very well at first, then water regularly after that. Other fertilizers may be mixed into a watering can and applied just like a regular watering. Follow any instructions on fertilizer packaging for consistency, but if you’d rather keep things on a regular schedule, shoot for every three to four weeks.

What happens if I fertilize my Cornflower too much?

Over-fertilizing is a very easy mistake to make for first-time gardeners, or even for experienced gardeners trying out a new product. Fortunately, Cornflower makes this issue known very well by displaying several signs of distress. You may notice that its leaves are yellowing quickly, the foliage may wilt, or new blooms may be under-developed. These are all clear signs of too much food. When you fertilize Cornflower too frequently, you create uninhabitable soil conditions. Soil may become too hot, which is a term used to describe when soil is too saturated with minerals, nutrients, or compost, and ends up burning the roots of anything planted in it. It’s a good idea to flush out the soil well once a month or so, just by watering twice as much as normal with good drainage.

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Key Facts About Cornflower

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Attributes of Cornflower

Lifespan

Annual, Perennial, Biennial

Plant Type

Herb

Planting Time

Mid spring, Late spring, Early summer

Bloom Time

Late spring, Summer, Fall

Harvest Time

Late summer, Early fall, Mid fall

Plant Height

20 cm to 1 m

Spread

15 cm to 30 cm

Leaf Color

Green

Flower Size

3.5 cm

Flower Color

Blue

White

Pink

Red

Purple

Violet

Fruit Color

Cream

Brown

Yellow

White

Tan

Stem Color

Green

Silver

Blue

Dormancy

Winter dormancy

Leaf type

Deciduous

Ideal Temperature

20 - 35 ℃

Growth Season

Summer

Pollinators

Bees

Growth Rate

Moderate

Name story

Bachelor button

The bachelor button is actually a flower that has a story behind it. This flower is generally worn when they have feelings for a certain person that they are trying to date. They would wear the flower and the longer that the flower lasted, the greater the presence of true love between the. If the flower wilts and dies, it isn’t meant to be.

Cornflower

In the past, it was often grown as a grass weed in cornfields where the field covers the plantation of wheat, barley, rye or oats. Hence, it gets the name, cornflower.

Symbolism

Being Single, Hope in love, Refinement

Usages

Garden Use

Cornflower (Centaurea cyanus) is a sun-loving garden favorite that produces showy blue flowers that look particularly attractive in combination with red poppies. This plant looks great in beds and borders, cottage gardens, and containers. Another asset of cornflower is that it attracts birds and butterflies.

Trivia and Interesting Facts

Cornflower is the national flower of Estonia and serves as a symbol for certain political parties in Estonia, Finland, and Sweden. It was also a favorite of many royalty figures across Europe, so it is found in plenty of historical regalia.

Scientific Classification of Cornflower

Phylum

Vascular plants

Class

Dicotyledons

Order

Asters bellflowers fanflowers and allies

Family

Daisy

Genus

Centaury

Species

Cornflower

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Common Pests & Diseases About Cornflower

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Common issues for Cornflower based on 10 million real cases

Dark spots

Dark spots, a kind of fungal disease, can seriously impact Cornflower. It causes spots on leaves, stems, and flowers, impacting the growth, aesthetic appeal, and overall health of the plant. Its control and prevention is crucial for maintaining the plant's health.

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.

Plant dried up

The entire plant may dry out due to dieback or normal seasonal dormancy.

Solutions: The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method. Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly. Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems. Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species. Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil. Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.

Leaf rot

This pathogen can cause the leaves to rot.

Solutions: Bacterial infections need to be treated quickly to prevent the spread to neighboring, healthy plants, potentially wiping out large sections of your indoor or outdoor garden. In mild cases: Use sterilized (10% bleach solution) pruning shears or scissors to remove any infected plant parts, making sure to dispose of them off site. Use a copper-based bactericide to treat the unaffected foliage, as well as the soil, and neighboring plants. Follow the manufacturer’s rate and timing directions found on the product label. In severe cases, where more than half the leaves are affected: Remove all of the infected plants from the garden, disposing of them off site. Treat the soil and neighboring plants using a copper-based bactericide. Follow the manufacturer’s rate and timing directions found on the product label.

Powdery Mildew

Powdery mildew is a white mold that appears on leaves. It can be wiped away.

Solutions: As powdery Mildew spores are transported by the wind, it can be tricky to put a complete stop to the spread of the fungus. Luckily, there are several easy treatments for plants that are exhibiting symptoms: If powdery Mildew seems to be impacting isolated leaves or stems, they can simply be trimmed away and disposed of. Disinfect pruning tools after doing this. Remove any plant debris from the ground around the infected plants and dispose of it in the garbage. Then, cover the soil with a thick layer of mulch to limit reinfection. Milk sprays have been found to be useful in controlling powdery Mildew. Make up a spray consisting of 60% water and 40% milk and spray on the affected plants. This can also be used as a preventative measure. In cases where powdery Mildew is more widespread, plants can be sprayed with a mild sulfur- or copper-based fungicide or a non-toxic solution made from baking soda and soap. Sprays can help areas that have been recently infected, though they are less effective against well-established infections. If possible, try transplanting the plants to a sunnier location. Though powdery Mildew does fine in hot, dry conditions, it is unable to reproduce without some humidity. Putting plants in more direct sunlight can help stop the spread of the fungus. Trimming around closely-packed plants can help improve airflow, which also prevents the reproduction of the fungus.

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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Weed Control About Cornflower

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Weeds

Native to parts of Asia and Europe, Centaurea cyanus has taken over the continental United States after escaping past its ornamental cultivation sites. Alaska, Georgia, West Virginia, and some parts of Maryland consider it to be an invasive species. Recognized by its delicate blue or white flowers, cornflower is typically viewed as ornamental by average households. On the other hand, farmers of cereals, corn, and rapeseed would find the cornflower to be a noxious weed to their crops due to the high competition for nutrients. Its resistance against herbicides has made it difficult to remove from farmlands.

How to Control it

The best time to remove weeds is before bearing fruits. Pulling out: For a small herb, wear gloves or use tools to dig weeds. Pruning: For an annual plant, pruning its aboveground parts can effectively control the growth. Plowing: Plow the soil before cultivation and bury the whole weed in the soil. Chemical control: If in large amounts, weeds can be removed by the herbicide.

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Distribution of Cornflower

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Habitat of Cornflower

Porous, nutrient-rich soils

Northern Hemisphere

South Hemisphere

Distribution Map of Cornflower

The cornflower plant is native to southern Europe, growing in meadows and other disturbed areas. Has also been widely introduced to many countries outside the native range. It is cultivated as a garden plant in the United States where it is also considered an invasive weed in agricultural fields.

Native

Cultivated

Invasive

Potentially invasive

Exotic

No species reported

More Info on Cornflower Growth and Care

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Basic Care Guide

Common Pests & Diseases

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Water

Every week

Cornflower, or Centaurea cyanus, originates from meadows and cultivated landfields throughout Europe. The region's moderate rainfall and relative humidity directly influence cornflower's watering needs. Cornflower sets a preference for even soil moisture, although it tolerates periods of drought. Mimicking these conditions in terms of watering frequency and soil drainage satisfies cornflower's hydration requirements, allowing it to flourish.

Watering Techniques

Lighting

Full sun

Cornflower thrives in environments where there is ample exposure to the sun for a significant portion of the day. It can also withstand conditions with moderate sun as well. Too much or too little light might impair the plant’s growth. In its native ecosystem, it typically grows under open skies, receiving generous sunlight.

Best Sunlight Practices

Transplant

12-18 inches

The ideal season for transplanting cornflower is during the time when new growth awakens, mainly early spring. Choose a location with full sun exposure and well-draining soil. Remember to gently loosen the root ball for optimal growth. Happy transplanting!

Transplant Techniques

Temperature

0 - 38 ℃

The natural habitat of cornflower flourishes in temperate climates. It notably prefers a heat range of 68 to 95 °F (20 to 35 ℃). Be mindful of seasonal changes and adjust temperatures accordingly.

Temp for Healthy Growth

Pruning

Spring, Summer, Autumn

A resilient wildflower with a profusion of blue blooms, cornflower thrives in a variety of conditions. Prune faded flowers regularly to promote continuous blooming. Cut back stems by a third post-flowering. Optimal pruning takes place from early spring to late fall. Pruning enhances air circulation and plant shape, preventing mildew in dense clumps. Thinning stems allows sunlight to reach the plant base, spurring new growth and robust health.

Pruning techniques

Propagation

Spring

Cornflower propagates easily through sowing in spring. Gently scatter the seeds on well-draining soil and lightly cover them. Look for new seedlings as a sign of successful propagation. Adequate sunlight and moisture are crucial for optimal growth.

Propagation Techniques

Pollination

Easy

The vibrant cornflower employs bees as its chief pollinators. These industrious insects are beguiled by the plant's vivid hues and bountiful nectar. Relying on an insect-mediated pollination method, cornflower times its flowering with precision, ensuring optimal pollen transfer during the active hours of bees. This captivating dance of nature ensures the propagation of the cornflower generation after generation.

Pollination Techniques

Dark spots

Plant dried up

Plant dried up' is a critical disease affecting Cornflower, resulting in dehydration and browning of leaves, ultimately leading to its wilting and death. Environmental factors and improper care predominantly cause this disease, posing severe threats to the longevity and health of the plant.

Brown blotch

Brown spot is a fungal disease that significantly impacts Cornflower. Manifesting as small, brown spots on leaves and stems, it hinders the plant's growth and vitality, causing substantial crop loss if left untreated.

Powdery mildew

Powdery mildew is a common fungal disease affecting Cornflower, causing powdery white patches on foliage, inhibiting photosynthesis, and hindering the plant's overall health and bloom. Effective treatment and prevention are vitally important.

Wilting

Wilting is a prevalent disease affecting Cornflower, causing its tissues to collapse and potentially leading to death. It's marked by a drooping appearance and often results from a lack of sufficient water and nutrients or attack by pathogens.

Flower withering

Flower withering is a devastating disease affecting Cornflower, causing premature wilting and weakened overall vitality. The disease is caused by various factors, manifesting physically through noticeable symptoms, predominantly during the warmer months.

Underwatering dry

Underwatering is a water-deficiency disease affecting Cornflower, resulting in withered, wilting plants and significantly reduced flowering. It’s not infectious but can be lethal and is completely preventable with careful watering practices.

Flower wilting

Flower wilting is a common disease affecting Cornflower, causing its iconic blue petals to wilt, losing their vibrant color and downward drooping. This condition threatens the plant's growth, reproductive prowess, and overall health.

Leaf rot

Leaf rot, a prevalent fungal disease, severely affects Cornflower by causing their leaves to darken, wilt, and eventually decay. High humidity and stagnant water catalyze the advancement of this disease, necessitating vigilant care and protection.

Feng shui direction

North

Cornflower is considered generally harmonious in Feng Shui due to its delicate and uplifting blue hue. Its positive energy may be well-suited for enhancing the support and guidance associated with a North-facing position, balancing the elemental interaction of water feng shui element.

Fengshui Details

Plants Related to Cornflower

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Crepe myrtle

Crepe myrtle (Lagerstroemia indica) is a highly ornamental small tropical tree or shrub, often multi-stemmed. It is native to India, Southeastern Asia, and Japan, and features a characteristic vase-shaped crown and beautifully-ruffled pink blooms that can last from early summer to autumn. It is also a popular nesting shrub for small birds.

Mexican mint

Not truly in the Oregano family, mexican mint or Coleus amboinicus is actually a perennial succulent from the mint family that is used for the same culinary purposes as oregano. Although it is often grown as a houseplant, mexican mint can be grown in the garden in warm weather. The flavor is exceptionally strong, so use a moderate amount of mexican mint when cooking.

Turkey berry

The Solanum torvum is a spiny and erect perennial plant that produces white, tubular flowers followed by edible berries. The berries are bitter in taste and often used in soups and sauces.

Old man's beard

Old man's beard (Clematis vitalba) is a deciduous climbing shrub that will grow to 12 m tall. It blooms with fluffy flowers and fruits that have long silky strands that look like the wispy beard of an old man. This plant is a food source for a variety of moths. Often seen scrambling over hedgerows, it is considered a noxious weed, especially in New Zealand. Evidence suggests ancient Europeans made rope and baskets with old man's beard.

Hairy clustervine

Hairy clustervine (Jacquemontia tamnifolia) is an annual sprawling vine that can grow to 30 cm tall and 3.5 m long. Heart-shaped foliage with delicate sky-blue flowers that bloom in summer. Flowers form clusters that last only a day as blossoms are replaced with fuzzy seed capsules. Considered a weed and not recommended for cultivation.

Woodbine

Woodbine (Parthenocissus vitacea) is a plant species native to the United States. This plant species attracts tumbling flower beetles and sweat bees. These insects collect pollen from its flowers.

Poison ivy

In pop culture, poison ivy is a symbol of an obnoxious weed because, despite its unthreatening looks, it gives a highly unpleasant contact rash to the unfortunate person who touches it. Still, it is commonly eaten by many animals, and the seeds are a favorite with birds. The leaves turn bright red in fall. Its sister species, Western poison ivy (Toxicodendron rydbergii), is not considered to be invasive in the United States, but is noxious in Australia and New Zealand.

Pokeweed

Although its berries look juicy and tempting, the fruits and the root of pokeweed are toxic and should not be eaten. Pokeweed is considered a pest species by farmers but is nevertheless often grown as an ornamental plant. Its berries can be made into pokeberry ink as well.

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Cornflower

Centaurea cyanus

Also known as: Garden cornflower, Bluebottle

Water

Every week

Sunlight

Full sun

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Care Guide for Cornflower

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Watering Care

Fertilizing Care

Pruning

Trim the diseased, withered leaves once a month.

Soil Care

Sand, Loam, Clay, Chalky, Acidic, Neutral, Alkaline

Repotting

Needs excellent drainage in pots.

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Questions About Cornflower

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Watering

Pruning

Sunlight

Temperature

Fertilizing

What is the best way to water my Cornflower?

What should I do if I water my Cornflower too much or too little?

How often should I water my Cornflower?

How much water does my Cornflower need?

How can I tell if i'm watering my Cornflower enough?

How should I water my Cornflower through the seasons?

How should I water my Cornflower at different growth stages?

What's the difference between watering Cornflower indoors and outdoors?

Is pruning necessary for my Cornflower?

How do I prune my Cornflower?

Are there any cautions I should be careful with when pruning my Cornflower?

Are there any tips for pruning my Cornflower?

When should/shouldn't I prune my Cornflower?

What should I look for when pruning my Cornflower in different seasons?

How much sunlight should Cornflower get per day to grow healthily?

What type of sunlight does Cornflower need?

Can sunlight hurt plants? How to protect Cornflower from sun and heat damage?

Should I protect Cornflower from sun exposure?

What will happen if Cornflower gets inadequate sunlight?

Does Cornflower need special care about sunlight during its different growth stages?

How much light does Cornflower need for photosynthesis?

Are there any cautions or tips for sunlight and Cornflower?

What is the optimal temperature for Cornflower?

Temperature requirements for first year or seedling Cornflower

How can I protect Cornflower from extreme temperatures?

Dormant season temperature recommendations for Cornflower

Why do I need to fertilize my Cornflower?

When is the best time to fertilize my Cornflower?

When should I avoid fertilizing my Cornflower?

What type of fertilizer does my Cornflower need?

How do I fertilize my Cornflower?

What happens if I fertilize my Cornflower too much?

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Key Facts About Cornflower

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Attributes of Cornflower

Lifespan

Annual, Perennial, Biennial

Plant Type

Herb

Planting Time

Mid spring, Late spring, Early summer

Bloom Time

Late spring, Summer, Fall

Harvest Time

Late summer, Early fall, Mid fall

Plant Height

20 cm to 1 m

Spread

15 cm to 30 cm

Leaf Color

Green

Flower Size

3.5 cm

Flower Color

Blue

White

Pink

Red

Purple

Violet

Fruit Color

Cream

Brown

Yellow

White

Tan

Stem Color

Green

Silver

Blue

Dormancy

Winter dormancy

Leaf type

Deciduous

Ideal Temperature

20 - 35 ℃

Growth Season

Summer

Pollinators

Bees

Growth Rate

Moderate

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Name story

Bachelor button

Cornflower

In the past, it was often grown as a grass weed in cornfields where the field covers the plantation of wheat, barley, rye or oats. Hence, it gets the name, cornflower.

Symbolism

Being Single, Hope in love, Refinement

Usages

Garden Use

Trivia and Interesting Facts

Scientific Classification of Cornflower

Phylum

Vascular plants

Class

Dicotyledons

Order

Asters bellflowers fanflowers and allies

Family

Daisy

Genus

Centaury

Species

Cornflower

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Common Pests & Diseases About Cornflower

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Common issues for Cornflower based on 10 million real cases

Dark spots

Learn More About the Dark spots

Flower withering

Flowers may dry out due to a sudden change in environment or because the plant has completed its normal flowering period.

Learn More About the Flower withering

Plant dried up

The entire plant may dry out due to dieback or normal seasonal dormancy.

Learn More About the Plant dried up

Leaf rot

This pathogen can cause the leaves to rot.

Learn More About the Leaf rot

Powdery Mildew

Powdery mildew is a white mold that appears on leaves. It can be wiped away.

Learn More About the Powdery Mildew

Underwatering

Leaves may wilt for a variety of reasons.

Learn More About the Underwatering

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Weed Control About Cornflower

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Weeds

How to Control it

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Distribution of Cornflower

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Habitat of Cornflower

Porous, nutrient-rich soils

Northern Hemisphere

South Hemisphere

Distribution Map of Cornflower

Native

Cultivated

Invasive

Potentially invasive

Exotic

No species reported

More Info on Cornflower Growth and Care

Basic Care Guide

Common Pests & Diseases

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Spring, Summer, Autumn

Plants Related to Cornflower

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Indoor

Requirements

Full sun

Ideal

Above 6 hours sunlight

Partial sun

Tolerance

About 3-6 hours sunlight

Watch how sunlight gracefully moves through your garden, and choose spots that provide the perfect balance of light and shade for your plants, ensuring their happiness.

Essentials

Preferred

Tolerable

Unsuitable

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Artificial lighting

Indoor plants require adequate lighting for optimal growth. When natural sunlight is insufficient, particularly in winter or in less sunny spaces, artificial lights offer a vital solution, promoting faster, healthier growth.
1. Choose the right type of artificial light: LED lights are a popular choice for indoor plant lighting because they can be customized to provide the specific wavelengths of light that your plants need.
Full sun plants need 30-50W/sq ft of artificial light, partial sun plants need 20-30W/sq ft, and full shade plants need 10-20W/sq ft.
2. Determine the appropriate distance: Place the light source 12-36 inches above the plant to mimic natural sunlight.
3. Determine the duration: Mimic the length of natural daylight hours for your plant species. most plants need 8-12 hours of light per day.

Important Symptoms

Symptoms of Insufficient Light in %s

Cornflower, a plant that thrives in full sunlight, is commonly grown outdoors with ample sunlight. When cultivated indoors with inadequate light, it may exhibit subtle symptoms of light deficiency.

(Symptom details and solutions)

Small leaves

New leaves may grow smaller in size compared to the previous ones once they have matured.

Leggy or sparse growth

The spaces between leaves or stems of your cornflower may become longer, resulting in a thin and stretched-out appearance. This can make the plant look sparse and weak, and it may easily break or lean due to its own weight.

Faster leaf drop

When plants are exposed to low light conditions, they tend to shed older leaves early to conserve resources. Within a limited time, these resources can be utilized to grow new leaves until the plant's energy reserves are depleted.

Slower or no new growth

Cornflower enters a survival mode when light conditions are poor, which leads to a halt in leaf production. As a result, the plant's growth becomes delayed or stops altogether.

Lighter-colored new leaves

Insufficient sunlight can cause leaves to develop irregular color patterns or appear pale. This indicates a lack of chlorophyll and essential nutrients.

Solutions

1. To ensure optimal growth, gradually move plants to a sunnier location each week, until they receive at least 6 hours of direct sunlight daily. Use a south-facing window and keep curtains open during the day for maximum sunlight exposure and nutrient accumulation.2. To provide additional light for your plant, consider using artificial light if it's large or not easily movable. Keep a desk or ceiling lamp on for at least 8 hours daily, or invest in professional plant grow lights for ample light.

Symptoms of Excessive light in %s

Cornflower thrives in full sun exposure and can tolerate intense sunlight. With their remarkable resilience, symptoms of sunburn may not be easily visible, as they rarely suffer from it.

(Symptom details and solutions)

Chlorosis

Chlorosis is a condition where the plant's leaves lose their green color and turn yellow. This is due to the breakdown of chlorophyll from excessive sunlight, which negatively affects the plant's ability to photosynthesize.

Sunscald

Sunscald occurs when the plant's leaves or stems are damaged by intense sunlight exposure. It appears as pale, bleached, or necrotic areas on the plant tissue and can reduce the plant's overall health.

Leaf Curling

Leaf curling is a symptom where leaves curl or twist under extreme sunlight conditions. This is a defense mechanism used by the plant to reduce its surface area exposed to sunlight, minimizing water loss and damage.

Wilting

Wilting occurs when a plant loses turgor pressure and its leaves and stems begin to droop. Overexposure to sunlight can cause wilting by increasing the plant's water loss through transpiration, making it difficult for the plant to maintain adequate hydration.

Leaf Scorching

Leaf scorching is a symptom characterized by the appearance of brown, dry, and crispy edges or patches on leaves due to excessive sunlight. This can lead to a reduction in photosynthetic capacity and overall plant health.

Solutions

1. Move your plant to the optimal position where it can receive abundant sunlight but also have some shade. An east-facing window is an ideal choice as the morning sunlight is gentler. This way, your plant can enjoy ample sunlight while reducing the risk of sunburn.2. It is recommended to trim off any completely dehydrated or withered parts of the plant.

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Indoor

Requirements

Ideal

Tolerable

Unsuitable

Just like people, each plant has its own preferences. Learn about your plants' temperature needs and create a comforting environment for them to flourish. As you care for your plants, your bond with them will deepen. Trust your intuition as you learn about their temperature needs, celebrating the journey you share. Lovingly monitor the temperature around your plants and adjust their environment as needed. A thermometer can be your ally in this heartfelt endeavor. Be patient and gentle with yourself as you explore your plants' temperature needs. Cherish your successes, learn from challenges, and nurture your garden with love, creating a haven that reflects the warmth of your care.

Essentials

The natural habitat of cornflower flourishes in temperate climates. It notably prefers a heat range of 68 to 95 °F (20 to 35 ℃). Be mindful of seasonal changes and adjust temperatures accordingly.

Regional wintering strategies

Cornflower has strong cold resistance, so special frost protection measures are usually not necessary during winter. However, if the winter temperatures are expected to drop below {Limit_growth_temperature}, it is still important to provide cold protection. This can be achieved by covering the plant with materials such as soil or straw. Before the first freeze in autumn, it is recommended to water the plant abundantly, ensuring the soil remains moist and enters a frozen state. This helps prevent drought and water scarcity for the plant during winter and early spring.

Important Symptoms

Symptoms of Low Temperature in Cornflower

Cornflower is cold-tolerant and thrives best when the temperature is above {Suitable_growth_temperature_min}. During winter, it should be kept above {Tolerable_growing_temperature_min}. When the temperature falls below {Limit_growth_temperature}, although there may not be any noticeable changes during winter, there may be a decrease in sprouting or even no sprouting during springtime.

Solutions

In spring, remove any parts that have failed to sprout.

Symptoms of High Temperature in Cornflower

During summer, Cornflower should be kept below {Suitable_growth_temperature_max}. When the temperature exceeds {Tolerable_growing_temperature_max}, the leaves of the plant may become lighter in color, prone to curling, susceptible to sunburn, and in severe cases, the entire plant may wilt and become dry.

Solutions

Trim away the sunburned and dried-up parts. Move the plant to a location that provides shade from the midday and afternoon sun, or use a shade cloth to create shade. Water the plant in the morning and evening to keep the soil moist.

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Care Guide for Cornflower

Questions About Cornflower

More Questions People Also Ask

Key Facts About Cornflower

Attributes of Cornflower

Name story

Symbolism

Usages

Trivia and Interesting Facts

Scientific Classification of Cornflower

Common Pests & Diseases About Cornflower

Weed Control About Cornflower

Distribution of Cornflower

Habitat of Cornflower

Distribution Map of Cornflower

More Info on Cornflower Growth and Care

Plants Related to Cornflower

Care Guide for Cornflower

Questions About Cornflower

More Questions People Also Ask

Key Facts About Cornflower

Attributes of Cornflower

Name story

Symbolism

Usages

Trivia and Interesting Facts

Scientific Classification of Cornflower

Common Pests & Diseases About Cornflower

Weed Control About Cornflower

Distribution of Cornflower

Habitat of Cornflower

Distribution Map of Cornflower

More Info on Cornflower Growth and Care

Plants Related to Cornflower