What's eating my thalictrum 'elin'?

Thalictrum 'Elin', a towering hybrid reaching 2.5 m, is as pest-resistant as the genus suggests. Slugs threaten the young shoots in spring before the plant reaches height. Powdery mildew can affect foliage in dry late summers. Aphids are an occasional minor visitor. No serious pest routinely devastates established plants of this magnificent cultivar.

Emerging spring shoots chewed at or just above soil level; leaves holed before the plant reaches its imposing mature height. Place ferric phosphate pellets around crowns as shoots emerge. Use a ring of sharp grit around the crown. Hand-pick on wet evenings; encourage natural predators.

Powdery white patches on leaves in late summer during dry periods; usually cosmetic on an otherwise vigorous plant of this size. Water deeply at the base during dry spells. Ensure adequate spacing for air movement. Remove infected foliage; a sodium bicarbonate or diluted neem spray can slow spread.

Light colonies on soft new stem tips; generally self-limiting on large, vigorous plants. Water jet to dislodge. Natural aphid predators (ladybirds, parasitic wasps) reliably control low-level infestations in a diverse border.