A Detailed Guide to Planting Large-flowered Coreopsis and Points to Note

Large-flowered coreopsis (Coreopsis grandiflora) is grown mainly for its flowers, which are generally yellow and have many petals, giving it very high ornamental value, so it is deeply loved by people. Large-flowered coreopsis currently attracts many people who want to plant it, but before planting, it is necessary to understand its planting techniques.

How to plant large-flowered coreopsis

1. Large-flowered coreopsis has low soil requirements, is cold-resistant and drought-resistant, and the suitable germination temperature is 15-20 degrees Celsius. It is easy to cultivate and can often self-propagate. In production, sowing or division propagation is mostly used, and cuttings can also be carried out in summer.

2. Sowing propagation is generally carried out in August, or direct sowing in the open field at the end of April in spring, flowering in July-August, with flowers continuing to bloom until mid-October. Biennial coreopsis flowers from late May to early June in early spring and continues to bloom until mid-October. To make coreopsis bloom more, remove spent flowers after flowering, apply one topdressing in July-August, and it will have abundant flowers and lush leaves by National Day.

Planting methods for large-flowered coreopsis

1. Soil. Large-flowered coreopsis is not strict about soil, preferring fertile, moist, well-drained sandy loam. It can grow in soil with a pH value of 5-8 formed by the weathering of slate, granite, sandstone and limestone, and grows best especially in soil with a pH value of 5-7 formed by granite weathering.

2. Sowing: The seeds of large-flowered coreopsis are relatively small, so broadcasting can be used for sowing. Mix the seeds with sand, spread them evenly on a previously prepared seedbed, and the seedbed should be about 15 cm higher than the surrounding ground to facilitate drainage.

3. Covering with soil: After the seeds are sown, cover with a thin layer of soil and water thoroughly.

4. Watering: Large-flowered coreopsis is drought-tolerant and afraid of waterlogging, so it should be drained promptly after rain.

5. Fertilizing: Apply nitrogen fertilizer 2-3 times during the growing period, and use phosphorus and potassium fertilizer together when applying nitrogen fertilizer. To make coreopsis bloom more, remove spent flowers after flowering, apply 1 topdressing in July-August, and it will have abundant flowers and lush leaves by National Day. Coreopsis has lush branches and leaves in fertile soil, but blooms less, so in order to achieve a good flowering effect, fertilization should be moderate and not excessive.

6. Pruning. The plants of large-flowered coreopsis are relatively tall and need pinching and pruning to maintain a graceful plant shape. Pinch once when the plant height is 6 cm, pinch a second time when the branches are 10 cm, and remove willow buds in time.

Points to note for large-flowered coreopsis

1. Seed collection and storage. Large-flowered coreopsis is suitable for sowing propagation, and seed collection and storage are very important. From August to October each year, select inflorescences with most of the fruit mature and cut them off, dry them in the sun, remove impurities, carefully select the seeds, place them in a dry and cool place, and pack them in moisture-proof paper bags. Store the seeds in a dry, dark, well-ventilated place at an ambient temperature of 10-15 degrees C; they still maintain a good germination rate after 1-2 a.

2. Common pests and diseases. Common pests of large-flowered coreopsis: aphids, cutworms and grubs. They can be killed by spraying omethoate, once every ten days. Common diseases of large-flowered coreopsis: powdery mildew and black spot. They can be controlled with dimethoate emulsifiable concentrate.

How large-flowered coreopsis propagates

1. Sowing propagation. Method: sowing can be carried out from March to April each year. Place the seeds directly on the sand, then cover with a thin layer of soil on top. Before sowing, water the soil thoroughly and evenly. After sowing, keep the soil at the same moisture level, cover with plastic film, then open the film in the morning and evening for ventilation, and cover it again at other times. When the seeds sprout, remove the plastic film and place them in a place with scattered light for growing. When 1 to 2 leaves have grown, they can be transplanted and set out.

2. Division propagation. Method: This method is very simple, because coreopsis itself has a strong ability to reproduce; simply dig out the divisions and plant them, and it can be done during its growing period. However, note that newly planted divisions should not be placed directly in the sun for exposure; wait until they have passed the seedling recovery period before carrying out normal care. It can also be propagated by cuttings, and cuttings can also be done in the hot summer, but this method is rarely used.

When planting large-flowered coreopsis, be sure to choose an appropriate time; both spring and summer are fine. After planting, be sure to control fertilizer and water well, and prune in a timely manner. If you want it to grow more, you can choose propagation, generally sowing and division propagation are more common.