How to Grow and Care Cornflower: Simple Tips
The traditional annual cornflower (Centaurea cyranus) is an excellent choice for flower gardeners. Its double 1 1/2-inch blossoms bear a striking resemblance to miniature carnations and are straightforward to cultivate. How to grow and care cornflower, originally found in meadows across Europe and Asia, the cornflower’s natural habitat was greatly diminished due to the use of modern herbicides. Without proper control, it has the tendency to spread rapidly through self-seeding. How to grow and care cornflower: however, it is still highly recommended that every gardener includes at least one “foolproof plant” in their garden, and the delicately scented cornflower is an ideal option for beginners.
How to grow and care cornflower, Cornflower’s dainty papery disks are encompassed by bracts, forming flowers that sit atop slender stems adorned with narrow gray-green leaves. When fully grown, these plants can reach heights of up to 48 inches and spread 12 inches wide across all growing zones. How to grow and care cornflower, their dense, vibrant blue blooms persist from spring to midsummer. Additionally, this species offers various cultivars with pink, white, and crimson blossoms.
Common Name: Cornflower, bachelor’s button
Botanical Name: Centaurea cyanus
Family : Asteraceae
Plant Type: Annual
Soil Type: Moist, well-drained
Soil pH: Alkaline
Bloom Time: Spring, summer
Flower Color: Blue, purple, pink, white, red
Mature Size: 12–48 in. tall, 10–12 in. wide
Sun Exposure: Full, partial
Hardiness Zones: 2–11 (USDA)
Native Area: Europe
Cornflower Care
Cornflower possesses a wide range of applications both in the landscape and at home. It can be incorporated into an ornamental vegetable garden, where its nectar-rich flowers attract pollinators that enhance the productivity of crops such as tomatoes, squash, and other reliant plants. Including cornflower in a wildflower garden is a great way to draw bees and butterflies. Moreover, it can be a delightful addition to a cutting garden when combined with annuals like orange cosmos or yellow marigolds.
Although cornflower can be obtained as a nursery start like most common annuals, it is also incredibly simple to cultivate from seed. Planting it amidst robust perennials such as rudbeckia or coneflower provides natural support for the stems. If desired, the plant can be staked to prevent it from flopping.
Typically, cornflower blooms for approximately 10 weeks, spanning from May to mid-July. However, by removing spent flowers through deadheading, the blooming period can be prolonged. Additionally, sowing the seeds in a spaced-out manner every two weeks can help extend the duration of the blooms. Cornflower is a wonderful choice for cut flowers or for drying. Harvest the blossoms at their peak before they start to wilt.
Light
Cornflower thrives in full sun, although it can tolerate some shade in the afternoon, particularly during the hot summer days. However, if exposed to shade throughout the entire day, the plant may become elongated and more susceptible to flopping.
Soil
For optimal growth, cornflower thrives in fertile garden soil that is well-drained and slightly alkaline, ideally with a pH ranging from 7.2 to 7.8. If your soil has a tendency to be acidic, incorporating crushed limestone into your garden beds can help adjust the pH level.
Water
Cornflower requires approximately 1 inch of water per week, particularly in the hottest months of July and August. It is important to allow the soil to slightly dry out between watering, but it should not be allowed to completely dry out, as this may cause the plant to flop. If the plant does wilt, giving it a good, thorough watering is usually enough to revive it.
Fertilizer
If your soil is of low quality, it is advisable to provide monthly fertilization for your cornflower using diluted liquid manure or compost tea. Begin the fertilization process in early spring when the young plants reach a height of 6 inches, and continue this practice throughout the summer. However, if your soil is already nutrient-rich, there is no need to provide additional feeding for your flowers. In many cases, simply incorporating a few bags of compost into the soil before sowing is sufficient for the entire season.
Climate and Moisture Level
When considering temperature, cornflower exhibits resilience to mild freezing as well as hot summer days. It flourishes within a temperature range of 60°F to 80°F, but to reach flowering maturity, it may require temperatures between 85°F and 95°F. Optimal growth for cornflower occurs within an average humidity range of 30% to 50%. However, it is important to monitor your garden closely during humid periods, as this plant is vulnerable to fungal diseases under such conditions.
Types of Cornflower
The majority of individuals are captivated by the classic, vivid blue cornflowers. This particular variety is commonly observed adorning roadsides and flourishing in rural pastures. However, there are also alternative cultivars that possess an equally appealing charm, showcasing blooms in shades of white, pink, or red.
Blue Boy: With its thistle-shaped flowers in a captivating periwinkle blue, ‘Blue boy’ is an heirloom variety that can be planted early in the spring to create a breathtaking display in your landscape.
Tall Double Mixed: For those seeking an excellent choice for a cutting garden, the ‘Tall Double Mixed’ series offers blooms in white, pink, and blue, perfect for creating attractive dried arrangements.
Blackball: For a unique and eye-catching option, consider the striking ‘Blackball’ variety, which features crimson poms that contain nectar highly sought after by birds.
Dwarf Blue Midget: is a well-suited option for beds, borders, and containers. It starts blooming when the plant reaches a height of 6 inches and reaches a maximum height of 12 inches, making it ideal for smaller spaces.
How to Prune
Although not essential for the growth of cornflower, pruning can prolong its blooming period. To achieve this, trim the long stems back to the secondary stems once the initial flowering phase of the plants is complete, typically occurring around mid-summer. Following the second bloom, either cut the plants back to ground level or remove them from the roots, allowing room for late-season plantings.
How to Grow from Seed
Propagation of cornflower from seed is a straightforward process, considering its natural ability to self-seed. You have the option of collecting seeds from dried flower heads and storing them during the winter for future planting, or you can easily acquire large and affordable packets of cornflower seeds.
Here’s a step-by-step guide on growing cornflower from seed:
- In late spring, once the last frost has passed, sow the seeds directly into the garden. There is no need to worry about planting too early, as the seeds will germinate when the conditions are suitable, guided by Mother Nature.
- Cover the seeds with approximately 1/2 inch of soil and ensure the seedbed is consistently watered and kept moist until germination takes place. In warm temperatures, this typically occurs within 10 days.
- Once the seedlings have emerged, thin them out to enhance both blooming and overall vigor in the plants.
- If you desire early flowering, you can start the seeds indoors. Begin this process six to eight weeks prior to the anticipated last frost by using a seed-starter mix in a seedling tray. Maintain the soil’s moisture and warmth until the seedlings sprout. Then, continue growing them in a bright location or sunny window until it is safe to transplant them outdoors.
Potting and Repotting Cornflower
For cornflower cultivation in pots or containers, it is important to maintain a soil moisture level that replicates the conditions found in pastures, leaning towards the drier side. Optimal container choices include porous clay or terracotta pots. When selecting the soil, prioritize a well-drained option containing perlite, or alternatively, consider utilizing a soilless medium composed of organic materials, resembling a cactus potting mix. Regularly removing spent flowers from your potted cornflower will ensure a tidy appearance. It’s important to note that when grown in this manner, the flowering season may be relatively short compared to other growing methods.
Common Pests & Plant Diseases
Cornflower, an annual plant with a brief growth period, typically encounters minimal issues with insects or diseases. However, in damp and humid conditions, powdery mildew can occasionally develop towards the end of the season, manifesting as white spots on the leaves. Although this fungal infection seldom poses a threat to the plant’s survival, treatment is generally unnecessary due to the plant’s short lifespan.
Occasionally, aphids and mealy bugs may make an appearance on a cornflower crop. To control their population, you can reduce their numbers by using bursts of water from a garden hose. It is important to avoid spraying pesticides, including organic ones, in the vicinity of cornflowers, as they can be detrimental to bees and other pollinators that rely on them for sustenance.
How to Get Bloom
For optimal blooming, cornflower thrives in bright and sunny conditions. Therefore, it is essential to choose a planting location that receives ample sunlight. While deadheading is known to stimulate additional flowering in many plants, it is considered unnecessary for this particular annual. If your cornflower is not producing blooms due to inadequate light, the best course of action is to plan accordingly for the following year and sow the seeds in a sunnier spot.
Common Problems
While uncommon, cornflower can be susceptible to fungal infections if it is overwatered and overcrowded. It is important to follow watering guidelines and thin out seedlings to promote adequate airflow around mature plants. In times of drought, cornflower is prone to wilting, which can lead to an unattractive appearance and the potential for plants to topple over. Typically, providing a sufficient amount of water will help revive them and restore their vigor.
