At a glance
- New growth curling down with insects underneath: Aphids; treat with insecticidal soap or neem oil
- Leaves rolled into tubes held with silk: Rose leafrollers; hand-pick or apply Bt/spinosad
- Stems twisting and leaves distorting asymmetrically: Herbicide drift; no cure, monitor for recovery
- Leaf edges curling under on hot afternoons: Heat stress or drought; water consistently and mulch
- Yellow mottling alongside curling: Rose mosaic virus; remove severely infected canes
Why rose leaves curl
Roses (Rosa spp.) are among the most widely grown garden plants, and curling leaves are one of the most common concerns rose growers bring to forums and garden centers. Unlike many plants where underwatering is the first thing to check, rose leaf curling is most often caused by pests, particularly aphids in spring and early summer and leafroller caterpillars through the growing season. Environmental causes including heat stress and herbicide damage also appear regularly. The pattern and location of the curling, combined with what is visible on the leaf surfaces, makes diagnosis straightforward in most cases. Here is what to look for.
Cause 1: Aphids
Signs: New growth and growing tips are curling downward and inward. Small soft-bodied insects are visible on the undersides of curled leaves and on stems near buds. The insects are typically green, pink, yellow, or black. A sticky, shiny residue (honeydew) may be on the leaves below, and black sooty mold may have developed on the honeydew. Ants may be climbing the canes. The damage is concentrated on the newest, most tender growth.
Why it happens: Roses are among the most aphid-prone plants in the garden. Aphids overwinter as eggs and hatch in spring to coincide with new rose growth. They cluster on soft new tissue, pierce it to feed on sap, and inject saliva that causes the leaf to curl down and inward around the colony, creating a protective environment. Populations can explode rapidly in warm weather, particularly if natural predators like ladybugs and parasitic wasps have been reduced by pesticide use.
Fix: Start with a strong jet of water to knock aphids off canes and leaves. A daily water blast for several days significantly reduces populations without chemicals. For heavier infestations, spray insecticidal soap or neem oil to both the upper and lower leaf surfaces, coating the curled leaves thoroughly. Repeat every 5 to 7 days for 2 to 3 applications. Avoid broad-spectrum insecticides that kill beneficial insects alongside the aphids. Encouraging ladybugs, lacewings, and parasitic wasps by avoiding pesticides provides longer-term control.
Cause 2: Rose leafrollers
Signs: Individual leaves are rolled lengthwise into a cylinder and held in position by fine silken threads. The rolled leaves may look like a small cigar or tube. Opening the roll reveals a small green, brown, or cream-colored caterpillar inside. Multiple leaves may be tied together in a bundle. The damage is scattered rather than concentrated on new growth only.
Why it happens: Several moth species produce larvae that roll and tie rose leaves as a feeding strategy. The most common in North America are the obliquebanded leafroller and the strawberry leafroller. The caterpillar rolls a leaf around itself to create a protected feeding shelter, cutting the leaf from the inside while remaining hidden from predators and contact sprays. Leafrollers are most active from late spring through summer and can produce multiple generations per year.
Fix: Hand-pick and destroy rolled leaves if numbers are manageable. Opening each roll and removing the caterpillar prevents it from completing its life cycle. For heavier infestations, apply spinosad or Bacillus thuringiensis (Bt) to the foliage when young caterpillars are active in spring before they roll into leaves. Once inside a roll, caterpillars are protected from most sprays. Timing treatment to the egg hatch period in early spring, before leaves are rolled, is the most effective approach.
Cause 3: Herbicide drift
Signs: The petioles (leaf stems) are twisting or curling in unusual ways, and leaves are distorting asymmetrically. Stems may be thickening or bending. New growth may be elongated and narrow. Multiple plants in the same area or downwind direction show similar symptoms simultaneously. The damage appeared suddenly, possibly after nearby lawn or agricultural herbicide application.
Why it happens: Roses are highly sensitive to broadleaf herbicides including 2,4-D, dicamba, and clopyralid, all of which are commonly used in lawn weed control. Even small amounts drifting from a neighbor's property on a warm, slightly windy day can produce dramatic distortion. The herbicides mimic plant growth hormones, causing uncontrolled cell elongation and the characteristic twisting and curling. Clopyralid can also persist in grass clippings used as mulch, reaching rose roots through the soil.
What to do: There is no chemical antidote. New growth emerging after the drift event may be normal if the exposure was light, and the plant may partially recover. Water the root zone to dilute any herbicide that settled in the soil. If clopyralid-contaminated mulch is suspected, remove it and replace with untreated material. Allow the plant several weeks to show whether recovery is occurring before making decisions about removal.
Cause 4: Heat stress and drought
Signs: Leaf edges are curling under on the hottest afternoons, particularly during heat waves. The curling relaxes overnight and the leaves look relatively normal in the morning. The soil is dry or inconsistently watered. The most affected leaves are on the most exposed parts of the plant. No insects are visible and no distortion is present.
Why it happens: Roses have moderate drought tolerance but high water demands during active growth and flowering. In peak summer heat, particularly above 90 degrees Fahrenheit, the leaves curl under to reduce their exposed surface area and slow water loss. This is a protective response, not permanent damage. Inconsistent watering that alternates between wet and dry conditions stresses the plant further and can contribute to other problems including black spot susceptibility.
Fix: Water deeply and consistently. Roses in the ground need approximately 1 to 2 inches of water per week during summer, more in hot climates. Apply a 2 to 3 inch layer of organic mulch around the base to retain soil moisture and keep roots cool. Water in the morning at the soil level rather than overhead to reduce fungal disease risk. Container roses may need daily watering in summer heat.
Cause 5: Rose mosaic virus
Signs: Yellow mottling, streaking, or ring spots appear on the leaves alongside curling or distortion. The patterns may be irregular and the leaf color looks uneven. Some canes may produce normal growth while others are clearly affected. The plant may be growing slowly. The symptoms are variable and often appear on some branches but not others.
Why it happens: Rose mosaic virus (RMV) is a complex of several viruses, most commonly Prunus necrotic ringspot virus and Apple mosaic virus, that are introduced through infected propagation material. Most commercial roses are grafted, and if the rootstock or scion was infected, the virus is present in the plant from the start. RMV does not spread from plant to plant in the garden; it travels only through propagation, grafting, or infected tools used for pruning. It does not kill roses but may reduce vigor and flowering somewhat.
What to do: There is no cure. Infected plants can be kept if they are performing acceptably. Remove severely affected canes with poor growth and disinfect pruning tools between cuts with diluted bleach or isopropyl alcohol. When purchasing new roses, buy from reputable nurseries that use virus-indexed propagation material. Avoid propagating from infected plants.