How to Grow Cornflower? A Detailed Guide to the Latest Cultivation Methods
Cornflower, also known as blue cornflower, jade blue, lychee chrysanthemum and so on, is an annual or biennial herbaceous plant of the genus Centaurea in the Asteraceae family, with extremely high ornamental value. Tall varieties have upright plants and long flower stalks, making them suitable for cut flowers and also usable as flowerbed material. Dwarf varieties grow only 20 cm tall and can be used for flowerbeds, lawn edging or potted flower displays. Now let us take a look at how to grow cornflower!
Cornflower's Growth Habits
The cornflower's homeland is Europe. It was originally a wild flower, and after many years of cultivation by people, its “wild” nature has diminished, its flowers have become larger and its colors more varied, with varieties in purple, blue, light red, white and so on, among which purple and blue are the most precious. It can be found everywhere on hillsides, in fields, by the water, along roadsides and around houses in Germany, and it is regarded as Germany's national flower. It has strong adaptability and likes sufficient sunlight, and is not tolerant of shade and dampness. It must be planted in a sunny place with good drainage, otherwise it often dies due to shade and dampness. It is relatively cold-resistant, likes coolness and avoids heat. It likes fertile, loose and well-drained sandy soil.
Cornflower's Propagation Methods
Cornflower seeds are generally sown in spring and autumn, with autumn being the better choice, roughly from mid-August to mid-to-late September. When planting, sow the seeds in an open-air seedbed, press lightly, then water an appropriate amount, cover with grass, and they can sprout quickly; after sprouts appear, remove the grass on top. Once the leaves grow to 6-7, they can be transplanted, and can be planted out in November. After that, apply a 1:5 diluted decomposed human manure liquid once every 10 days or half a month, until February to March of the following year. Pot sowing requires fertile, loose soil, and it is recommended to add mixed soil such as leaf mold.
Cornflower's Cultivation Methods
1. Planting out: After cornflower seedlings are planted out and have survived, pinch them once to encourage more branching and more flowers. Conversely, if there is too much branching, some side buds should be removed when necessary to obtain larger flowers. Because it has a taproot, it is best to sow it directly; sow in autumn, cover in the open field to overwinter, and it will bloom in early summer. If overwintered in a cold frame, it can bloom in late spring. For spring sowing, sow as early as possible. It blooms in June.
2. Potting soil: The potting soil for cornflower should be loose and fertile. It is best to choose fertile sandy soil with good looseness and drainage. It is best to use a mixed soil of garden soil, leaf mold, plant ash and so on, and to maintain good ventilation to facilitate drainage. If the soil is too clayey, 30-40% tree fern chips or perlite can be mixed into the soil.
3. Temperature: Cornflower has strong cold resistance. It can be planted in the open field in East China, while in North China it must be covered to overwinter. When grown as cut flowers, greenhouses are usually used to force blooming: sow in August, plant out in September, and flowers can be produced in February of the following year. In warm areas within the passes, it is generally sown in August to September, covered in the open field to overwinter, planted out in early spring of the second year, and blooms in early summer. In Northeast China, it is sown in spring in greenhouses.
4. Watering: Cornflower is not tolerant of shade and dampness. Generally, watering once a day is enough to meet its needs, but in hot and dry summer weather, water once in the morning and once in the evening to meet water needs and cool the soil at the same time. Be careful not to water too much and cause accumulation in the pot.
5. Fertilizing: Cornflower likes abundant fertilizer and needs fertile soil. During the growing period, apply a diluted liquid fertilizer of the three elements once a month. If the leaves are too lush, reduce the proportion of nitrogen fertilizer. Before flowering, apply more phosphorus and potassium fertilizer to obtain larger flowers with beautiful colors.
Precautions for Cornflower
1. Cornflower is robust in nature, relatively cold-resistant and likes sunlight, and requires fertile, loose and well-drained soil.
2. Base fertilizer should be applied before planting out cornflower. Because cornflower has a taproot system and is not tolerant of transplanting, a larger soil ball must be kept when transplanting.
3. Cornflower stems are thin and weak and tend to lodge, so the planting distance should not be too dense. Prevent overly dense growth and poor ventilation that can cause lodging.
4. During the seedling stage, cornflower needs topping and pinching to encourage more branching and dwarf the plant, so that it blooms more and has a graceful plant shape.
5. During the growing period, apply liquid fertilizer once every 20 days to cornflower, but note that too much nitrogen fertilizer should not be applied. An appropriate amount of more phosphorus and potassium fertilizer should be applied to make the stems firm and the flower colors bright.
6. Cornflower should be watered in appropriate amounts, not too much. During the rainy season, be sure to drain promptly, otherwise it will cause root rot and affect the normal growth of the plant.