Why Are My Rose Shoots Covered in Greenfly?

Dense clusters of small, soft-bodied green, yellow or pink insects massed on the soft growing tips and flower buds of roses are greenfly — a specific term for the several aphid species that favour roses, most notably Macrosiphum rosae, the rose aphid. They are among the most familiar rose pests and appear reliably in late spring and early summer, often seemingly overnight as populations build from nothing to thousands in just a few days.

The damage aphids cause

Aphids pierce the soft tissue of young shoots and buds and extract phloem sap. Affected shoots become distorted, curled and stunted. Flower buds may fail to open normally or produce malformed flowers. Heavy infestations cause the tips to wilt even in moist conditions. Aphids also excrete a sticky, sugary waste product called honeydew, which coats leaves and provides a growing medium for sooty mould fungus, leaving a black coating on the foliage.

Natural predators — let nature help

Ladybirds, lacewings, hoverflies and parasitic wasps all feed on or parasitise rose aphids, and a garden with diverse planting supporting these beneficial insects will usually see natural control kick in by early summer. If you spray indiscriminately with insecticides, you kill these predators alongside the aphids, and populations rebound faster and to higher levels. Planting nectar-rich flowers nearby encourages beneficial insects to take up residence.

Physical removal

Squashing or rubbing off aphid colonies with gloved fingers is highly effective for small infestations and does not harm beneficial insects or the environment. Alternatively, blast the colonies off with a firm jet of water from a hose. Aphids knocked to the ground rarely make their way back up to the plant. Do this on several consecutive days to knock back the population before it can recover. This approach is particularly useful in late spring before natural predators arrive in numbers.

Soap and oil sprays

A spray made from diluted soft soap or insecticidal soap kills aphids on contact by disrupting their cell membranes. It has minimal effect on beneficial insects once dry. Neem oil is another organic option. Both require thorough coverage — aphids on the underside of leaves or inside curled tissue will not be reached. Repeat every 5–7 days while colonies persist.

Chemical control as a last resort

If physical and organic methods are not keeping pace with a severe infestation, a systemic insecticide containing acetamiprid or thiacloprid will provide faster knockdown. Use with caution: systemic products are taken up by the plant tissue and may reach nectar and pollen, potentially harming bees and other pollinators. Apply in the evening when pollinators are inactive and avoid spraying open flowers.