One of my favorite flowers, bachelor buttons are sometimes called cornflowers. And it’s from there that the color “cornflower blue” derives its name!
Also called basket flowers, blue bonnets, blue cap and many other names, this popular plant is a hardy annual. It blooms from early spring through the fall months in an array of color. Leave some of the spent flowers on the plant, and it’ll happily reseed its bed and grow again next year.
But what are bachelor’s buttons, and are they all blue? Do they prefer sunlight or shade? How much water do they need? We’ll cover all this and more today as we explore the world of the bachelor’s button!
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Bachelor Buttons Overview
| Common Name | Bachelor buttons, bachelor’s button, blue cornflower, blue cap, bluecup, blue blob, blue bonnets, cornbottle, boutonierre flower, hurtsickle, gogglebuster, basket flower, blue boy |
| Scientific Name | Centaurea cyanus |
| Family | Asteraceae |
| Light | Full sun preferred, can tolerate some shade |
| Water | Drought-tolerant, maybe 1” per week at most |
| Soil | Prefers loamy, well-drained soil but can take poor soils, pH range 6.6-7.8 |
| Fertilizer | Minimal fertilizer if any at all. Compost at base of plant is plenty of nutrition. |
| Pests | Aphids, mealybugs. May be nibbled by rabbits. Some birds eat the seeds. Invites beneficial insects & pollinators. |
| Diseases | Powdery mildew and rust |
All About Bachelor’s Buttons
Bachelor button has a long list of names that includes such unusual ones as “blue blob”, “cornbottle”, “gogglebuster” and “hurtsickle”. One name, cornflower, originated with these plants’ tendency to grow as a native plants in cornfields in Europe.
Botanically, it’s called Centaurea cyanus and commonly named bachelor button, blue cornflower, or bachelor’s buttons. This name refers to old folklore. Young love-struck men would wear them on their lapel. If the early flowering bloom faded fast, it was thought the object of their desire didn’t love them.
While declining in its natural habitat, the growth of this plant worldwide has expanded via gardens designed for cut flowers. Many varieties are blue. However, bachelor button can be pink, purple, and white as well.
Grey-green or silvery-green slender foliage with long, lanceolate leaves forms the base upon which bright flowers form. It can reach up to three feet in height and can sprawl out 1-2 feet wide. The greyish or silvery tint is actually caused by fine white hairs on the leaves.
This annual’s self-sowing tendency has caused them to become listed on the USDA’s list of introduced, invasive, and noxious plants. North Carolina has become so plagued by it that selling its seeds or live plants is prohibited in that state!
Their edible flowers can be used in salads as a touch of added color. Petals are often dried and added to loose tea blends for a pop of color. In addition, the flowers are a historical pigment or dye source for painting or dyeing fabric.
Caring For Bachelor’s Buttons
Of all the flowers you can grow, bachelor button flowers will be some of the easiest to grow year after year. You can fine-tune care to gain perfect conditions, but they’ll grow well even in poor locations!
Light & Temperature
Bachelor button plants prefer full sun but can tolerate partial shade. They need lots of light to produce their array of flowers. Be sure to plant them in an area where they’ll receive ample daylight!
Temperature-wise, these plants are tough. Young seedlings can tolerate light freezes and often germinate in the late winter & early spring. Weaker plants will die back. Hardier plants continue to survive and flourish.
The blue cornflower tolerates heat, but in the most extreme heat conditions may need extra attention to keep them healthy.
Water & Humidity
Surprisingly drought-tolerant, bachelor button can tolerate everything but muddy conditions. These are not fussy plants on the whole. After all, they grow wild in many regions!
Whenever possible, avoid watering these plants from overhead. Ensure that they don’t sit in areas that develop standing water.
Cornflowers can live in humid environments, but you should provide adequate airflow to reduce the risk of fungal disease.
Moisture on the leaves of blue cornflower can promote the formation of mildew. Excessive water at the root zone can cause root rot. Do what you can to avoid these conditions!
Soil
In its natural environment, bachelor’s buttons grow in loamy and well-drained soil. They’re very tolerant of other soil types as well. If possible, avoid soil that becomes extremely wet, as that can endanger the plant’s health!
Also, the cornflower can be grown in neutral soils through soils with quite a bit of alkalinity. A 6.6 to 7.8 pH range is favorable for these plants, although an optimal range would be best at around 6.9-7.4. This provides the little bit of alkalinity they like without going too far over.
Fertilizer
Most soil types provide ample nutrition for your bachelor button plants. If you’d like to give them a boost, work in some compost or a balanced slow-release fertilizer before planting bachelor button seeds.
Every month or two, spread some compost around the base of your blue cornflower. This should provide lots of nutrition and guarantee you’ll have plenty of flowers throughout the year.
Propagation
Seed is the easiest way to propagate these plants and the way that most people choose. You can sow seeds directly in the soil or start them in containers.
Once your soil’s prepared, mist it to dampen the surface, and then tuck the seeds just beneath the surface of the soil. They will germinate in 7-14 days. Once germinated, you should thin them down to one plant each 8-12″ or so. I recommend 12″ for extra growing space.
Your plants will fill in the space once they begin to really push up leaves and stems, and in time they’ll flower. These flowers can produce open-pollinated seeds for next year if you’d like!
To collect seeds from your bachelor button plants, wait until the flowers have faded naturally on the plant and fully dried. Cut the flower off of its stalk, and then break it up to reveal the seeds hiding within. The seeds are oblong in shape with a tuft of brownish hair at the end.
Allow your seeds to dry for 7-10 days in a cool, dry location, and then store them until the next planting season.
Repotting
Growing the bachelor button flower in pots is also optional, and they don’t need repotting. As long as you begin with a pot that is about a foot wide, one plant will cheerfully grow in its available space until it dies back in the fall.
Opting to start plants in containers indoors to replant outside? Replanting is very simple.
Prepare your soil in advance, dig a hole that will fit the plant and most of its soil ball, and then gently unpot. Make sure its roots aren’t too intertwined, then place it soil and all in its new location. Gently backfill with fresh soil.
Place a thin layer of compost over the soil at the plant’s base, and you’re done!
Pruning
Bachelor button plants can become unruly if they’re not supported. I’ll go into that in more detail in the support section.
If you choose to let them grow unsupported, too much wind can cause them to bend or lean. Trim off growth that gets in the way of pathways or other plants if you wish, or use them as cut flowers. Aesthetics define the pruning necessity here.
Deadheading your flowers is also a good choice. When you don’t deadhead spent flowers, they will self-seed the plot and spring right back up the next year! This also promotes more flowering.
Support
As I said above, your plants are probably going to need some support. Since these can reach 3 feet tall, they can become a weedy tangle of bent stems if you don’t offer an assist!
One of the simplest ways to support cornflowers is to place four short wooden stakes at the corners of your bed. Stretch a piece of chicken wire or nylon mesh between these stakes and use staples to anchor it in place.
As your seedling plants grow, they’ll stretch through the wire or mesh. This provides some low-level support against windy or rainy conditions. It also keeps small animals like rabbits away from the base of your plants.
Bachelor Button Problems
Bachelor’s buttons have very few pest or disease issues. Read on to learn how to defeat any which appear!
Growing Problems
The biggest problem that you’re likely to encounter is top-heavy plants. This is quite common with bachelor’s button, and is caused by excess moisture on the flowers.
Using supports for your plants is the only real way to fix this. The stems are so slender that it’s easy to see how they can topple under the weight!
Another problem which may appear is yellowing foliage. Most often, this problem’s caused by a watering issue. Both over-watering and under-watering may be to blame.
Make sure that your soil drains well and that standing water cannot pool around your plants. Aim for consistent soil moisture, not too wet but not completely dry either.
Yellowing leaves can also be a sign of frost damage, and if this occurs, the plant may still survive. If it begins pushing out new growth in the spring, trim off yellowed leaves. Remember, this is an annual plant, and overwintering may not be an option.
Pests
Very few pests will bother cornflowers. In fact, it’s likely that only a couple sucking insects will stop by for a snack.
Some types of aphids may take up residence on or under leaves. These can be wiped out by applying neem oil on all plant surfaces. The oil smothers eggs and kills the adults.
Mealybugs are another sucking insect that may snack on your plant. While bachelor’s button is not their first choice, they still may be at risk. Use insecticidal soap to end their stay.
In addition to these, I’ve discovered that rabbits will nibble on the leaves of your plants. They won’t eat enough to do severe damage, but they do like the taste!
In the non-pest department, small birds find the seeds delicious. They may also help get rid of caterpillars or other pests, so I consider them to be helpful.
Many beneficial insects are drawn to the flowers. Ladybugs will help to eliminate aphids. Pollinating insects such as bees will make your garden thrive!
Diseases
Very few diseases will cause damage to your bachelor buttons. Here are two which might appear if you’re not careful!
Getting rid of powdery mildew can be a slow process. Neem oil works well but may take multiple applications. Weekly sprayings will reduce the chances of powdery mildew or pest infestation.
Spread by wind-borne spores, rust may also appear. This fungal disease causes yellow or white spots on top of leaves. Over time, spores appear on the underside of the leaves, and the plant’s growth may become stunted.
Copper fungicides such as Monterey Liqui-Cop can help eliminate rust when it appears. Remove any damaged leaves and destroy them, and spray all plant surfaces with the fungicide.
Frequently Asked Questions
Q: Are bachelor buttons perennials or annuals?
A: They are annual.
Q: Are bachelor buttons sun or shade?
A: Bachelor’s button plants require either full sun or partial shade.
Q: Are bachelors buttons invasive?
A: In some areas, they are. Before you plant them, check with your local extension office to see if they are.
Q: Why do they call them bachelor buttons?
A: Bachelor’s button plants were put in the lapels of bachelors. Their rate of fading determined the strength of the love between the bachelor and the person he courted.
Q: When should I cut back my bachelor buttons?
A: Cut them back at the end of their growing season, or before they grow too tall.
Q: How long do bachelor buttons last?
A: They bloom from anywhere between 4 and 10 weeks.
Q: Can bachelor buttons survive frost?
A: No. They will die back in extreme cold or heat.
Q: Are bachelor buttons easy to grow?
A: Yes! Try growing them!
