Doronicum, or leopard's bane, is a cheerful early-flowering perennial with one important quirk: it goes completely dormant in summer, and the curling, yellowing leaves that appear from late spring onward are often just the plant beginning its normal seasonal shutdown. Understanding this life cycle prevents unnecessary alarm. That said, aphids on spring growth, powdery mildew, slug damage, virus, and root rot can each cause genuine leaf curling problems during the active growing period.
1. Summer dormancy
Summer dormancy is the most common reason doronicum leaves curl and die, and it is entirely normal. Doronicum is a spring ephemeral that produces its growth, flowers, and sets seed during the cool months and then retreats underground when summer heat arrives. From late May or June onward the leaves naturally yellow, curl, and wither as the plant draws energy back into its rhizomes. This can look alarming to gardeners who are not familiar with the plant's lifecycle, but it is not a disease, pest, or cultural problem.
The plant is not dead: its rhizomes remain dormant underground through the summer and push up fresh leaves again in late summer or early autumn. In a warm summer with limited moisture, dormancy may begin slightly earlier and proceed more quickly than usual.
What to look for
- Leaves yellowing and curling from late spring to early summer
- Timing follows naturally after flowering finishes
- All leaves on the plant affected uniformly
- No pest, fungal coating, or soil problem visible
- Plant produced healthy flowers earlier in the same season
How to fix it
Nothing needs to be done except to mark the position so the dormant plant is not accidentally disturbed or overplanted. Cut off the dead foliage once it has fully yellowed and collapsed: the rhizomes are underground and unaffected. Plant a summer-growing neighbour such as hostas, ferns, or hardy geraniums nearby to fill the gap left when doronicum goes dormant. Fresh growth will return from late summer onward, and the plant will flower again the following spring.
2. Aphids
Doronicum's brief active growing season in early spring coincides with the emergence of aphid populations, and the soft new growth is an attractive target. Aphids cluster at the growing tips and on the undersides of the first emerging leaves, feeding on sap and injecting growth-disrupting toxins. The result is curled, misshapen growing tips and distorted young leaves that do not open properly. Because doronicum flowers early and then dies back, aphid damage in spring can compromise the entire season's ornamental display.
What to look for
- Small green or yellow-green aphids at growing tips and leaf undersides
- Growing tips curled or cupped and failing to unfurl
- Sticky honeydew on stems and lower leaves
- Distortion on the earliest emerging growth in spring
- Ants farming the colony on the plant
How to fix it
Act promptly because doronicum's active season is short. Knock aphids off with a firm water jet or apply insecticidal soap directly to the colony. Pinching out the most heavily infested growing tip removes the colony and the worst of the damage in one action. Encourage natural predators by avoiding broad-spectrum insecticides: ladybirds and parasitic wasps are active at the same time as aphids in spring and provide significant free control. Once the aphids are dealt with, any subsequent growth during the remaining spring period will be undamaged.
3. Powdery mildew
Powdery mildew can infect doronicum in late spring, particularly in warm dry spells following a cool wet period. The fungal coating appears on the leaf surface and causes the margins to curl upward. Because doronicum is approaching dormancy at this point, mildew infection rarely causes lasting harm: the leaves would die back within a few weeks regardless. However, a heavy infection in a cool spring while the plant is still actively growing can reduce flowering quality.
What to look for
- White or grey powdery coating on the leaf surface
- Leaf margins curling upward around the mildewed tissue
- Symptoms appearing in late spring after flowering
- Often affecting the lowest and most congested leaves first
- Plant otherwise at the normal stage of seasonal decline
How to fix it
Remove badly affected leaves and dispose of them in the bin. Improve airflow around the plant by thinning neighbouring plants. Water at the base only and avoid overhead irrigation. Because dormancy is approaching, treating mildew on doronicum is often unnecessary: cutting off the dying foliage as it reaches the end of the season removes the infected tissue entirely. For future seasons, avoid planting doronicum in enclosed spots with poor air movement, and divide congested clumps in autumn to improve circulation.
4. Slugs
Slugs target doronicum's emerging growth in early spring when the soft new leaves are at their most vulnerable. Feeding on an unfurling leaf before it has expanded causes the tissue to develop unevenly and emerge already curled or misshapen rather than flat. The typical irregular holes and slime trails of slug damage are visible on affected leaves, and the damage is most severe in wet springs when slug activity is high.
What to look for
- Irregular holes and ragged edges on emerging spring leaves
- Young leaves curled or distorted, failing to open flat
- Silvery slime trails on foliage and soil in the morning
- Crown area disturbed or leaves pulled into the soil
- Damage worst after rainy nights in early spring
How to fix it
Patrol around the plant after dark in early spring and collect slugs by hand. Apply iron phosphate pellets around the emerging growth, renewing after rain. Biological control with Phasmarhabditis hermaphrodita nematodes is effective when soil temperature is above 5 degrees C. Remove debris and loose mulch from immediately around the crown that provides daytime shelter for slugs. Because doronicum flowers early and briefly, protecting the spring growth from slug damage is especially important for getting a good display.
5. Virus
Several viruses can infect doronicum, typically transmitted by aphids or contaminated tools. Infected plants display leaf distortion and curling combined with unusual mosaic or mottled patterns of yellow, pale green, or dark green on the leaf surface. The curling associated with virus infection is irregular and often accompanied by puckering or a generally stunted appearance. Unlike aphid damage which is confined to the tips, virus symptoms spread through the whole plant over time.
What to look for
- Leaves curled and distorted throughout the plant, not just at growing tips
- Yellow, pale, or dark mottled patterns on leaf surfaces
- Overall stunted or distorted appearance compared to healthy plants
- No aphids, powdery mildew, or soil problem visible
- Symptoms appearing across the whole plant progressively
How to fix it
There is no cure for virus-infected plants. Remove and destroy the affected plant entirely to prevent aphids from feeding on it and carrying the virus to neighbouring plants. Do not compost infected material. Disinfect any tools used near the plant with a diluted bleach or methylated spirits solution. Control aphid populations in the garden to reduce the risk of virus transmission between plants. Replace the doronicum with a healthy plant from a reputable source and plant it in a different position.
6. Root rot
Doronicum grows from fleshy rhizomes that are vulnerable to rotting in waterlogged soil, particularly during the wet winter and spring months when the plant is most active. Infected rhizomes turn brown and soft, and the plant's ability to deliver water to the leaves is compromised. Leaves curl and wilt even when the soil is wet. The problem is most common in heavy clay soils or in spots where water collects after rain.
What to look for
- Leaves curling and wilting despite wet or waterlogged soil
- Rhizomes brown, soft, or foul-smelling when the plant is lifted
- Problem appearing after wet winter or spring weather
- Only some sections of the clump affected while others remain healthy
- No aphids or mildew to explain the symptoms
How to fix it
Lift the plant and cut away all rotted rhizomes to healthy firm tissue. Allow the healthy sections to dry briefly, then replant in improved, well-drained soil enriched with grit and organic matter. Doronicum grows best in moist but freely draining conditions: it needs moisture retention in spring but not waterlogging over winter. In persistently wet soils, raise the bed level or incorporate substantial amounts of coarse grit. Dividing the clump every three to four years and discarding any soft or suspect sections prevents minor rot from spreading through the whole plant.
Quick diagnosis checklist
| What you see | Most likely cause | First action |
|---|---|---|
| Leaves yellowing and curling from late spring after flowering | Normal summer dormancy | Mark position, cut back dead foliage, wait |
| Growing tips curled, aphids visible in spring | Aphids | Water jet, insecticidal soap, remove infested tip |
| White powder on leaves, margins curling in late spring | Powdery mildew | Remove affected leaves, improve airflow |
| Irregular holes, distorted emerging leaves, slime trails | Slugs | Night patrol, iron phosphate pellets in spring |
| Mottled yellow-green patterns, distortion across whole plant | Virus | Remove and destroy the plant |
| Wilting despite wet soil, soft brown rhizomes | Root rot | Lift, cut away rot, replant healthy sections |
Frequently asked questions
Why are my doronicum leaves curling and dying in summer?
Doronicum is a spring-blooming perennial that goes naturally dormant in summer. The leaves curling, yellowing, and dying back from late spring onward is normal behaviour, not a disease. The plant stores energy in its rhizomes underground and reappears in late summer or autumn with fresh growth. Mark the position so you do not accidentally disturb the dormant rhizomes.
Can aphids damage doronicum leaves?
Yes. Aphids target the soft new growth emerging in early spring when doronicum is most active. They cluster at the growing tips and cause the young leaves to curl and fail to open normally. Because doronicum's growing season is short, aphid damage in early spring can reduce the quality of the flowering display significantly. Treat early with insecticidal soap or by removing the colony by hand.
Does doronicum get powdery mildew?
Yes, powdery mildew can affect doronicum in late spring before the plant goes dormant. Look for a white powdery coating on the leaf surface combined with marginal curling. Because doronicum is about to die back anyway, mildew at this stage rarely causes long-term harm. Removing the worst affected leaves tidies the plant but treating is usually unnecessary.
Why has my doronicum disappeared?
Doronicum goes completely dormant in summer and the leaves die back entirely, leaving no visible sign of the plant above ground. This is completely normal. The rhizomes are alive below the soil surface and will produce fresh growth in late summer or early autumn. Mark the spot with a label so the dormant plant is not accidentally dug up or overplanted.