Why Are My Cleome Leaves Curling?

Aphid infestation

Aphids are the most common pest on cleome. They colonise the shoot tips, the undersides of the palmate leaves, and the sticky stems, where their feeding causes the leaves to curl, pucker, and distort. The sticky, glandular nature of cleome stems means that aphid colonies can become trapped and difficult to dislodge, and the combination of aphid honeydew and the plant's own secretions creates a particularly sticky surface that attracts ants. Heavy infestations weaken the plant and reduce flowering.

What to do

• Inspect the shoot tips and undersides of curling leaves for aphid colonies. Green and black aphids are both common on cleome.
• Spray the plant with insecticidal soap every four to five days for two to three weeks, ensuring coverage of the sticky undersides of leaves and the shoot tips.
• A jet of water helps dislodge aphids from firmer parts of the plant before chemical control.
• The flowers of cleome attract beneficial insects including hoverflies and parasitic wasps that provide natural biological control of aphid populations.

Drought stress

Despite being a large, robust annual, cleome has big, palmate leaves with significant water demand, particularly as the plant grows rapidly through early summer. In dry conditions or in containers where the compost dries between waterings, the leaves wilt and curl rapidly. Cleome is more heat-tolerant than many summer annuals and can recover from brief drought quickly, but prolonged water stress reduces flowering and makes the plant more vulnerable to pest attack.

What to do

• Water established border plants during prolonged dry spells, particularly from late June through August when the plant is at its most active and producing flowers continuously.
• Mulch around the base of established plants with 5 cm of garden compost to retain soil moisture through dry periods.
• Container-grown cleome needs watering every two to three days in warm weather. Check the compost daily and water before the leaves show stress symptoms.
• Feed container plants weekly with a balanced liquid fertiliser to maintain vigour through the long growing season.

Cold damage

Cleome is frost-tender and must not be planted outside until the risk of frost has fully passed, typically late May in most of the UK. Young plants put out too early are frequently caught by late frosts or cold nights: the large, soft leaves develop water-soaked patches, curl, collapse, and turn black. Even without frost, cold nights below 5 degrees Celsius cause the leaves to curl and look bleached or translucent. Plants that have been hardened off properly before planting are significantly more resilient to cold snaps.

What to do

• Harden off cleome transplants thoroughly for at least two weeks before planting out, starting with sheltered daytime exposure and gradually increasing duration and cold.
• Plant out only after late May when night temperatures are reliably above 8 to 10 degrees Celsius.
• Cover with fleece if a cold snap is forecast in early summer after planting.
• Cold-damaged leaves and shoot tips should be removed once warmer weather returns: the plant will regrow from healthy stem tissue below the damaged section.

Overwatering

Although cleome benefits from regular watering, it does not tolerate consistently waterlogged soil. In heavy clay or in containers without drainage, the roots rot and the plant declines. Yellow, curling leaves despite wet compost, combined with a general loss of vigour, indicate root damage from waterlogging. Container-grown cleome is particularly at risk in cool, overcast spells when the compost takes much longer to dry than in sunny weather.

What to do

• Plant cleome in well-drained soil. On clay soils, improve drainage with grit and organic matter before planting.
• In containers, ensure adequate drainage holes and use a free-draining compost blended with perlite.
• Reduce watering frequency during cool or overcast periods.

Spider mite

Spider mite can affect cleome in hot, dry conditions, particularly in sheltered positions or when plants are growing in the warmth of a greenhouse or polytunnel. The large palmate leaves develop fine bronzing or stippling on their upper surface, the leaves curl, and fine webbing appears between the leaflets as the infestation develops. Because cleome grows tall, spider mite infestations on the upper foliage may go unnoticed until significant damage has occurred.

What to do

• Examine the undersides of curling leaves for the tiny mites and their webbing, working upwards through the plant from the base.
• Spray thoroughly with insecticidal soap or neem oil every five to seven days for four to six weeks.
• Increase air humidity around the plant: spider mites dislike moist conditions and are inhibited by regular misting of the foliage.

Frequently asked questions

Why are my cleome leaves curling?

Cleome leaves curl most often from aphid infestation or drought stress. Aphids colonise the shoot tips and the undersides of the palmate leaves, causing them to curl and distort. Drought causes the large leaves to wilt and curl quickly in warm weather, though cleome is more heat-tolerant than many other annuals.

Why are my cleome leaves sticky?

Cleome stems and leaves are naturally covered in sticky, glandular hairs that produce a pungent, musky scent. This stickiness is a natural characteristic of the plant and can trap small insects. It is not a sign of disease or pest damage, though aphid honeydew can add to the stickiness if an infestation is present.

How often should I water cleome?

Cleome is reasonably drought tolerant once established in the ground but benefits from regular watering during dry spells to maintain its vigour and continuous flowering. Water when the top 5 cm of soil feels dry. Container-grown cleome needs watering more frequently, every two to three days in warm weather.

Why are cleome leaves turning yellow and curling?

Yellow curling leaves on cleome indicate overwatering, nutrient deficiency, or the natural ageing of lower leaves as the plant matures and the main stem grows taller. If yellowing affects the whole plant and the soil is wet, root rot is likely. Feed container-grown plants weekly with a balanced liquid fertiliser.