Why Are My Moluccella Leaves Curling?

Aphid infestation

Aphids are the most common pest on moluccella. They cluster at the shoot tips, on the undersides of the large leaves, and particularly within the whorls of green calyces as the flower spire develops. The sheltered spaces within the calyces provide ideal protected feeding territory, and colonies can build up significantly before becoming visible from outside the plant. Aphid feeding causes the leaves to curl and pucker, and heavy infestation distorts the developing calyx spire, which is the main ornamental feature of the plant.

What to do

• Inspect the undersides of the large leaves and part the calyces to check within the developing spire for aphid colonies.
• Spray with insecticidal soap every four to five days for two to three weeks, directing the spray into the calyx whorls where colonies shelter.
• A jet of water dislodges aphids from the large leaves effectively as a first step before applying insecticidal soap.
• Avoid high-nitrogen fertilisers which produce soft, lush growth that is especially susceptible to aphid attack.

Drought stress

Moluccella has large leaves with significant water demand, and the plant wilts and curls rapidly when the soil dries out, particularly in containers or in free-draining soils during warm spells. The large calyces on the developing spire also lose their firm, upright posture and begin to droop when the plant is water-stressed. Drought stress is a common problem with moluccella in UK gardens during the warm, dry weeks of July and August when the plants are at their most productive for cutting.

What to do

• Water moluccella regularly during dry spells, particularly in July and August when the plants are developing their cutting spires.
• Mulch around border plants with garden compost to retain soil moisture and reduce the frequency of watering required.
• Container-grown moluccella needs watering every two to three days in warm weather: the large leaves transpire significant amounts of water in full sun.

Overwatering

While moluccella needs consistent moisture, it does not tolerate persistently waterlogged soil. In containers without adequate drainage or in heavy clay soils, the roots deteriorate and the plant declines. Yellow, curling leaves despite wet compost, combined with soft stems at the base, indicate root damage. Container-grown plants on a fixed watering schedule are most at risk during cool, overcast periods when the compost takes much longer to dry between waterings.

What to do

• Plant moluccella in well-drained soil. On clay, improve drainage with grit and organic matter before planting.
• In containers, use free-draining compost and ensure excellent drainage holes. Allow the surface of the compost to dry between waterings.
• Reduce watering frequency during cool or overcast periods.

Cold damage

Moluccella is half-hardy and should not be planted outside until after the last frost, typically late May to early June in most of the UK. Young plants exposed to temperatures below 5 degrees Celsius develop translucent, water-soaked patches on the large leaves, which then curl, collapse, and turn brown. Cold damage can also occur after a warm spring if a late cold snap follows planting. Hardening off is essential before planting out to help plants tolerate temperature fluctuations.

What to do

• Harden off moluccella transplants for at least two weeks before planting out.
• Plant out only after late May when nighttime temperatures are reliably above 8 degrees Celsius.
• Cover with fleece if a cold snap is forecast after planting. Cold-damaged leaves should be removed cleanly once warmer weather returns.

Spider mite

Spider mite can affect moluccella in hot, dry conditions, particularly on plants grown under glass or in very warm, sheltered positions outdoors. The large leaves develop fine stippling or bronzing on the upper surface, the leaf edges curl, and fine webbing appears between the stems and within the calyx whorls. Because the calyces create sheltered, warm spaces, spider mite populations can develop rapidly within the spire before becoming apparent from outside.

What to do

• Examine the undersides of leaves and look within the calyx whorls for the tiny mites and their webbing.
• Spray with insecticidal soap or neem oil every five to seven days for four to six weeks, directing the treatment into the calyx spire.
• Increase air humidity around the plant: spider mites are inhibited by moist conditions and regular misting of the foliage.

Frequently asked questions

Why are my moluccella leaves curling?

Moluccella leaves curl most often from aphid infestation or drought stress. Aphids colonise the shoot tips and developing spires, causing the leaves and the characteristic green calyces to curl and distort. Drought causes the large leaves to wilt and curl rapidly, particularly in containers or during warm settled spells.

Why is my moluccella going yellow?

Yellowing moluccella leaves suggest overwatering, nutrient deficiency, or the natural senescence of the lower leaves as the plant matures and the flower spire develops. If the whole plant is yellowing and the compost is wet, root rot is likely. Feed container-grown plants weekly with a balanced liquid fertiliser to maintain the rich green colour.

How do I dry moluccella successfully?

Cut moluccella stems when the calyces are well-developed but before the small white flowers within them have fully opened and dropped. Strip the leaves from the stems. Hang upside down in small bunches in a warm, dry, well-ventilated space away from direct light. Drying takes two to three weeks. The calyces retain their distinctive shape and papery texture when dried.

When should I sow moluccella?

Moluccella is best sown under glass in March or April at 18 to 20 degrees Celsius, as the seeds germinate erratically and slowly at lower temperatures. Chill the seeds in the refrigerator for one week before sowing to improve germination. Plant out after the last frost in May or June in a warm, sheltered position in full sun.