How to grow Cleome hassleriana? Detailed growing methods and precautions

Cleome hassleriana, also known as Cleome spinosa, purple dragon whiskers, spider flower, etc., is an annual or biennial herbaceous plant of the genus Cleome in the family Cleomaceae, native to tropical America. Its petals are light and graceful, and when in full bloom they look like butterflies dancing, which is quite interesting. It can be used to arrange flower beds and flower borders in summer and autumn, and can also be dwarf-cultivated and grown as a potted ornamental. Now let us take a look at the growing methods for Cleome hassleriana!

Growth habits of Cleome hassleriana

Cleome hassleriana is native to tropical America and is cultivated for ornamental purposes from the tropics to temperate zones worldwide. It has strong adaptability, prefers high temperatures, is relatively tolerant of summer heat, and dislikes cold. It likes sunny locations, and can also grow well in semi-shaded locations. It is not demanding about soil. In fertile soil with sufficient water and fertilizer, the plants grow tall; in general soil with medium fertility, they can also grow well; in sandy loam, somewhat heavy clay soil, or alkaline soil, growth is poor. It likes moist soil, is also relatively tolerant of drought, and dislikes waterlogging.

Propagation methods for Cleome hassleriana

1. Sowing: Sow Cleome hassleriana seeds in an open-field seedbed in mid-April, and seedlings emerge uniformly. The seedlings grow slowly, so thinning must be done in time after sowing. Transplant when they have 2 to 3 true leaves. Set them in the ground or pot them in June. During the growing period, fertilize once every half month. If too much fertilizer is applied, the plants tend to grow leggy, affecting plant form and flowering. Generally, those sown in spring bloom in autumn, while those sown in autumn bloom indoors in winter and spring.

2. Cuttings: The substrate for Cleome hassleriana cuttings is nutrient soil, river sand, peat soil, etc. The optimum temperature for rooting of cuttings is 18 to 25°C. Below 18°C, the relative air humidity must be kept at 75 to 85%. Humidity can be increased by misting the cuttings, and 50 to 80% of sunlight must be shaded out. After the root system grows out, gradually remove the shade net.

Growing methods for Cleome hassleriana

1. Soil: Cleome hassleriana does not need special soil, but a well-drained sandy soil containing humus is best. Except for poor growth in alkaline soil, it can grow in sandy soil and clay soil, and grows best in slightly acidic sandy loam. Equal parts leaf mold and vegetable garden soil can be mixed as the growing medium.

2. Potting: When potting Cleome hassleriana, first place a 2 cm thick layer of coarse-grained substrate or ceramsite at the bottom of the pot, sprinkle a layer of fully decomposed organic fertilizer on top as base fertilizer, about 1 to 2 cm thick, then cover with a layer of substrate about 1 to 2 cm thick, and then place the plant in, so as to separate the fertilizer from the roots and avoid burning the roots.

3. Fertilizing: Like other herbaceous flowers, Cleome hassleriana has a relatively high demand for fertilizer and water, but the principle of “light fertilizer applied frequently, small amounts more often, complete nutrition” should be followed, and after fertilizing, the leaves and flowers should be kept dry at night. During the bud stage in pots, apply 2 to 3 times of dilute compound liquid fertilizer, and it can bloom during the Spring Festival.

4. Pinching: Before flowering, Cleome hassleriana is generally pinched twice to encourage more flowering branches. One to two weeks after potting, remove the top shoot, keeping 3 to 4 leaves at the lower part, to encourage branching. Carry out the second pinching 3 to 5 weeks after the first pinching. When planted in flower beds, spent flowers should be removed in time.

5. Watering: Cleome hassleriana is relatively tolerant of drought, but grows better when given higher air humidity. Water every day in midsummer, and water thoroughly. It likes higher air humidity; if the air humidity is too low, individual flowers fade faster. It also fears rain, and the leaves need to be kept dry at night. The optimum relative air humidity is 65 to 75%.

6. Light: Cleome hassleriana likes high temperatures and tolerates summer heat. The optimum growing temperature is 20°C to 32°C. It likes sunshine and warmth, tolerates heat, is slightly tolerant of semi-shade, and is not cold-tolerant. When frost occurs, the plants die. Although it can also grow under semi-shade conditions, in order to keep it dwarf, it should receive as much direct light as possible, preferably more than 4 hours per day.

7. Pests and diseases: Cleome hassleriana is often harmed by leaf spot disease and rust disease. For leaf spot disease, spray with 50% thiophanate wettable powder at 500 times dilution; for rust disease, spray with 50% carboxin wettable powder at 3000 times dilution for control. During the seedling stage, lepidopteran pests are prone to appear, and the insecticide abamectin at 4000 times dilution can be used for foliar spraying.