Alchemilla mollis, or lady's mantle, is one of the most forgiving and self-sufficient garden perennials, but its distinctive pleated leaves will curl and lose their fresh appearance when the plant is under stress. Drought is the most common trigger, but aphids (including invisible root-feeding forms), sawfly larvae, slugs, powdery mildew, and crown rot each produce recognisable symptoms. Understanding the cause prevents wasted effort and gets the plant looking its best again quickly.
1. Drought stress
Drought is the most common cause of leaf curling in alchemilla. Despite its reputation as a tough, low-maintenance plant, alchemilla has a relatively shallow root system and its large pleated leaves are efficient at losing moisture in hot or dry conditions. The leaves lose their normal gently cupped posture and the edges curl upward and inward as water pressure in the cells falls. In severe drought the plant may also look flat and limp, with older outer leaves going yellow at the margins.
Plants growing on hot, dry south-facing slopes or in very sandy, free-draining soil are most at risk. Alchemilla in partial shade with regular moisture holds its appearance much better through summer than plants in full sun on poor dry soil.
What to look for
- Leaf edges curling upward and inward across the whole plant
- Soil dry below the surface near the crown
- Outer, older leaves yellowing at margins
- Leaves losing their characteristic velvety grey-green texture
- Recovery within hours of deep watering
How to fix it
Water deeply and apply a mulch of bark chip or leaf mould over the root zone to retain moisture. Alchemilla looks best when given consistent moisture through the growing season. After a period of drought stress, cut the plant back entirely to the crown: the leaves that have been curled will not fully recover, but fresh, perfectly formed new leaves will replace them within two to three weeks. This midseason cutback is standard practice for alchemilla regardless of drought, as it refreshes the whole plant and prevents excessive self-seeding.
2. Aphids
Alchemilla is susceptible to two types of aphid that cause leaf curling in different ways. Above-ground aphids cluster at the growing tips and in the leaf axils, injecting growth-disrupting toxins as they feed. Young leaves that were developing when the aphids arrived emerge already curled or puckered and remain permanently distorted. Root aphids are less visible but more damaging over time: they colonise the base of the root system and cause leaves to curl, yellow, and wilt as the roots are progressively weakened. Root aphid infestations often go undiagnosed because there is nothing to see at leaf level.
What to look for
- Young leaves curled or failing to open flat
- Green or grey aphids visible at growing tips or in leaf axils
- Sticky honeydew on stems and lower leaves
- Wilting and curling with no above-ground pests (check root base for white waxy residue)
- Ants farming a colony on or near the plant
How to fix it
For above-ground aphids: apply insecticidal soap directly to the colony or knock them off with a firm water jet. Cutting the plant back entirely removes the infested growing tips and the colony in one action, and the replacement growth will be undamaged. For root aphids: lift the plant, wash the root zone thoroughly, repot in fresh compost, and drench with insecticidal soap solution. Encourage natural predators by avoiding broad-spectrum insecticide sprays that eliminate ladybirds and parasitic wasps.
3. Sawfly larvae
Several sawfly species lay their eggs on alchemilla, and the pale green larvae that hatch can cause significant leaf damage. The larvae feed on the leaf surface, rasping away the tissue from the underside and leaving the upper surface intact but translucent. As the damaged cells dry and collapse, the leaf curls around the injury. A heavy infestation can defoliate sections of the plant quickly, leaving skeleton leaves that curl and brown.
What to look for
- Pale green caterpillar-like larvae on the leaf underside
- Translucent or skeletonised patches on leaves
- Leaves curling and browning around the skeletonised areas
- Larvae feeding in groups, often detected by looking at the underside
- Damage from late spring through summer
How to fix it
Check the undersides of leaves regularly from late May and remove larvae by hand as soon as you spot them, dropping them into soapy water. Colonies caught early are straightforward to deal with. For heavier infestations, apply insecticidal soap to the leaf underside, covering every larva. Cutting the plant back entirely after a sawfly attack and watering well allows fresh, undamaged growth to replace the affected leaves quickly.
4. Slugs
Slugs target the soft, young alchemilla leaves as they unfurl from the crown in spring. Feeding on an expanding leaf prevents it from developing normally, and the leaf emerges with irregular holes and a curled or puckered shape that persists throughout the season. Mature leaves can also be attacked, with the slug rasping channels through the tissue that cause surrounding cells to dry and curl. The characteristic slime trails left on and around the plant confirm slug activity.
What to look for
- Irregular holes and ragged edges on emerging spring leaves
- Young leaves curled or distorted in an uneven pattern
- Channels or hollowed-out patches on mature leaves
- Silvery slime trails on foliage and soil
- Damage worst in spring and after wet weather
How to fix it
Patrol around the crown after dark in spring and collect slugs by hand. Apply iron phosphate pellets around the emerging growth in April and May, renewing after rain. Biological control with Phasmarhabditis hermaphrodita nematodes is effective when soil temperature is above 5 degrees C. Remove debris and leaf litter from around the crown that provides daytime shelter. A ring of coarse grit around individual crowns deters slugs but needs refreshing after rain.
5. Powdery mildew
Powdery mildew is less common on alchemilla than on many other perennials, but it can appear in warm dry summers with poor air circulation, particularly on plants growing in sheltered borders or against walls. The white powdery coating appears on the upper surface of the pleated leaves and causes the margins to curl upward and the tissue to lose its crisp, velvety texture. Mildew on alchemilla is rarely severe enough to cause lasting harm but makes the plant look unattractive.
What to look for
- White powdery coating on the upper leaf surface
- Leaf margins curling upward and losing their normal cupped shape
- General tatty, tired appearance of the foliage
- Worst in sheltered spots with poor air movement
- Symptoms from midsummer onward
How to fix it
Cut the plant back entirely to the crown: this removes all infected foliage and is the simplest and most effective response. New growth emerging will be clean and undamaged. This cutback aligns with the normal midseason practice of removing alchemilla's faded flowers and tired foliage anyway, so it involves no extra harm to the plant. Water and feed lightly after cutting back. Improve airflow by thinning crowding neighbours.
6. Crown rot
Alchemilla grows from a woody crown that is generally resilient but can rot in persistently waterlogged conditions, particularly during wet winters. The crown tissue softens and discolours, and the plant's ability to transport water upward to the leaves is progressively impaired. Leaves curl and yellow, starting from the outermost and working inward, and the plant eventually collapses. The problem is most common in heavy clay or in spots where surface water pools after heavy rain.
What to look for
- Leaves curling and yellowing from the outermost inward
- Crown soft, discoloured, or foul-smelling at the base
- Problem appearing after wet weather or in heavy clay
- Roots brown or mushy when the plant is lifted
- No pests or drought to explain the symptoms
How to fix it
Lift the plant and cut away all rotted crown and root tissue to firm, healthy growth. Dust cut surfaces with sulphur powder. Replant in improved, well-drained soil enriched with coarse grit. Alchemilla tolerates a wide range of soils but requires adequate drainage: it grows naturally in moist mountain meadows and woodland edges where the soil is well-aerated even when moist. In persistently wet gardens, raise the bed level or add substantial grit to the planting hole.
Quick diagnosis checklist
| What you see | Most likely cause | First action |
|---|---|---|
| Leaf edges curling up, soil dry | Drought | Water deeply, mulch, cut back if severe |
| Young leaves curled, aphids visible or waxy root residue | Aphids | Insecticidal soap; lift if root aphids suspected |
| Pale larvae on underside, skeletonised patches curling | Sawfly | Remove larvae by hand, insecticidal soap |
| Irregular holes, distorted young leaves, slime trails | Slugs | Night patrol, iron phosphate pellets |
| White powder on leaves, margins curling up | Powdery mildew | Cut plant back entirely to crown |
| Leaves curling and yellowing from outside in, crown soft | Crown rot | Lift, cut away rot, replant in drained soil |
Frequently asked questions
Why are my alchemilla leaves curling upward?
Alchemilla leaves curling upward at the edges most often indicate drought stress. The distinctive pleated, fan-shaped leaves lose their normal cupped posture and curl as cells lose water. Check the soil below the surface: if it is dry, water thoroughly and apply a mulch over the root zone. Alchemilla usually recovers quickly once watered.
Can aphids curl alchemilla leaves?
Yes. Root aphids are a particularly common problem on alchemilla, colonising the base of the root system invisibly and causing leaves to curl, yellow, and wilt as the root is weakened. Above-ground aphids on the growing tips distort young emerging leaves. Lift a wilting plant to check for white waxy aphid residue at the root base if no soil dryness or other cause is obvious.
Should I cut back alchemilla when the leaves curl?
Yes. Cutting alchemilla back hard to within a few centimetres of the crown after the frothy yellow-green flowers fade is standard practice. It removes any curled, scorched, or mildewed foliage, prevents self-seeding, and encourages a fresh flush of attractive leaves for late summer and autumn. Water and feed lightly after cutting back.
Why do alchemilla leaves curl in summer heat?
Alchemilla naturally looks less fresh in midsummer heat: the leaves may cup and curl as they lose moisture in high temperatures. This is a stress response rather than a disease. Cutting the plant back immediately after the flowers fade and watering well refreshes it completely, and the new growth emerges looking crisp and healthy.