What's eating my dahlia?

Dahlias are heavily targeted by earwigs (eating petals at night), aphids on new shoots, slugs and snails on emerging tubers and young stems, thrips inside flowers, and deer and rabbits browsing foliage. Earwigs and slugs together cause the most consistent, widespread damage — earwigs are particularly notorious for eating dahlia petals unseen overnight.

Feed at night inside flower heads and on petals, leaving irregular holes in blooms and jagged leaf edges; damage is most visible on the morning after a warm night and can ruin show blooms entirely. Trap in upturned pots filled with straw on canes; empty traps into soapy water each morning; keep surrounding ground clear of debris where earwigs shelter during the day.

Newly emerging shoots from tubers are eaten at soil level; young stems may be severed; slime trails are the diagnostic sign. Apply iron phosphate pellets when shoots first emerge in spring; use copper tape around containers; hand-pick at night; mulch with sharp grit.

Dense colonies on soft stem tips and buds cause distorted growth, sticky honeydew, and ants farming the colonies; can transmit dahlia mosaic virus. Pinch off infested tips; blast off with water; apply insecticidal soap or neem oil; encourage ladybirds; avoid high-nitrogen feeding that promotes lush, sappy growth.

Deer browse dahlias heavily — they eat stems, leaves, and flowers down to stubs overnight; rabbits nibble lower stems and foliage on young plants. Erect deer fencing (at least 1.8 m high); use repellent sprays on foliage; protect individual plants with wire cages; plant in walled or enclosed gardens where possible.