What's eating my achillea ptarmica 'the pearl'?

Achillea ptarmica 'The Pearl' is a vigorous spreader with double white flowers and few serious pest enemies. Aphids and spittlebugs are the most common nuisances. Slugs may target emerging spring shoots. Because 'The Pearl' spreads by runners it usually grows away from minor damage quickly, making significant pest damage unusual.

Green aphid colonies on soft shoot tips and flower stems in spring and summer; honeydew and light distortion at growing points. Knock off with water. 'The Pearl' flowers attract beneficial predatory insects; allow natural control to work before applying soap or neem oil.

Characteristic white foam blobs on stems in early summer, housing a single sap-sucking nymph; rarely causes lasting harm. Remove by hand or with a water spray. No chemical treatment required — the plant's vigorous growth easily compensates for any minor damage.

Feeding on young stems and foliage at soil level in spring, leaving ragged margins and slime trails; spreading clumps usually compensate rapidly. Apply ferric phosphate pellets in early spring. Avoid thick mulch immediately around crowns as it provides shelter. Grit around the base deters slugs effectively.