Pest
Aphids
What it is
Tiny sap-sucking insects that cluster on soft new growth, causing curling and leaving a sticky honeydew that attracts ants and sooty mould.
How to identify it
Dense colonies of green, black or grey soft-bodied insects on shoot tips and leaf undersides; distorted new growth.
How to treat it
Squash or hose off small outbreaks, or spray with soapy water or horticultural soap. Ladybirds and hoverflies clean them up if you avoid broad sprays.
How to prevent it
Encourage beneficial insects with flowers like alyssum and marigold, avoid over-feeding with nitrogen, and check new growth regularly.
Treatment guidance is general and organic-first; check current advice for your area before using any product.