Coreopsis (scientific name: Coreopsis drummondii Torr. et Gray) is an annual or biennial herbaceous plant of the genus Coreopsis in the Asteraceae family. It can reach a height of 60 cm. Its leaves are pinnately parted, with lobes ranging from round-ovate to oblong. The capitulum is solitary at the branch tips. The outer involucral bracts are nearly equal in length to the inner ones. The ray florets are yellow, with a purple-brown base and a blackish-purple appearance. The achenes are obovate. It flowers from July to September.
Propagation Methods
Seed Propagation:
(1) Seedbed preparation: Coreopsis is usually sown indoors in pots in early spring. A sowing pot or wooden box with a diameter of 30 cm and a depth of 5 cm is typically used. Cover the drainage hole with broken tile pieces, then add coarse gravel 1/3, coarse culture soil 1/3, and sowing soil 1/3 in sequence. Then, use a wooden stick to press and level the soil surface, keeping the soil 1 cm below the pot rim. After soaking the pot soil thoroughly using the "pot immersion method," lift the pot out and wait until the water has completely seeped in before sowing.
(2) Sowing method: When sowing Coreopsis, open the seed bag and scatter the seeds evenly into the pot, or mix the seeds with fine sand and then scatter them evenly into the pot. After sowing, cover with a thin layer of fine soil, then cover the surface with glass, and place newspaper over the glass to reduce water evaporation.
(3) Seedling stage management: Before the Coreopsis seeds sprout, keep the soil moist. Do not let the seedbed alternate between dry and wet, or become overly dry or overly wet. In the morning and evening, lift the glass for a few minutes to allow ventilation, and keep it covered during the day. After the seeds germinate and emerge, remove the covering promptly and gradually expose them to light. Once 1-2 true leaves have grown, transplant them.
Division Propagation: Every spring and autumn, divide the base of the mother plant into two or more parts for planting.
Cutting Propagation: In summer and autumn each year, the mother Coreopsis plant readily produces many stolons, and many young branches grow on these stolons. These young branches can be used for cutting propagation.
Cultivation Techniques
1. Soil: It is best to plant Coreopsis in loose, well-aerated soil rich in humus. Before planting Coreopsis, loosen the soil. Loosening the soil after rain helps the Coreopsis roots breathe. Weed once a week during the rainy season.
2. Watering: Coreopsis is easy to cultivate. Water thoroughly once after planting, then control watering to prevent the plant from growing leggy.
3. Light: Coreopsis likes direct sunlight and tends to grow leggy in overly shady environments. It is a short-day plant, and short-day conditions can ensure that Coreopsis blooms vibrantly.
4. Fertilizing: Before planting Coreopsis, rotted leaves can be used as a base fertilizer in the soil (1 kg/sq m). When Coreopsis transitions from the growth stage to the flowering stage, stop fertilizing. Apply top dressing after 4 flower buds have formed.
5. Pruning: When Coreopsis grows to 6 cm tall, pinch once. When the branches reach 10 cm, pinch a second time, and promptly remove willow buds.