Why Are My Rose Leaves Rolled Into Tubes?

Rose leaves that are tightly rolled along their length into neat cigar-shaped tubes have been manipulated by the leaf-rolling sawfly (Blennocampa phyllocolus). The adult female uses a chemical she injects into the leaf to cause the rolling behaviour — the leaf is not eaten, but curls around itself to form a protective case for her eggs. By the time you notice the rolling, she may have already moved on, and the leaf contains a tiny egg or larva inside.

Life cycle and timing

The adult sawfly is a small, dark wasp-like insect that is active in late spring, typically May and June. She lays eggs in rose leaflets and injects a chemical that causes the leaf to roll and wrap around the egg, providing both shelter and food for the emerging larva. The larva feeds on the rolled leaf tissue before dropping to the ground to pupate in the soil, emerging as an adult the following spring. There is one generation per year.

Removing rolled leaves

Pick off and bin (do not compost) every rolled leaf you can find on the plant. This removes the egg or larva before it completes its development and falls to the ground, reducing the population for the following year. Check the plant regularly throughout May and June — the rolling occurs over several weeks as different females visit. The plant will produce replacement leaves rapidly and rarely suffers lasting damage from this pest.

Will the plant recover?

Yes, almost always. Rose leaves are produced in flushes and the plant quickly replaces removed leaves with healthy new growth. Even a heavily attacked plant that loses many leaves in May will be growing strongly again by July. The main concern is cosmetic — rolled leaves look untidy and conspicuous — rather than a genuine threat to plant health. Only very young or already stressed plants are significantly weakened by heavy leaf-rolling sawfly attack.

Pesticide options

Contact insecticides are of limited use because by the time you notice the rolling, the female has gone and the larva is protected inside the sealed leaf. If you can spray directly onto an adult that you observe in the act of egg-laying, pyrethrum or insecticidal soap will kill it on contact. For most gardeners, physical removal of rolled leaves is more practical and effective than trying to spray.

Reducing populations year on year

Because the pupae overwinter in the soil, disturbing the soil beneath and around affected roses in autumn (by forking or mulching with fresh material) exposes pupae to birds and frost, reducing the spring population. A deep, coarse-textured mulch also prevents pupae from accessing the soil surface easily. Neither method eliminates the pest entirely but both noticeably reduce numbers.