What's eating my thalictrum aquilegiifolium?

Thalictrum aquilegiifolium (columbine meadow rue) is largely pest-free. Slugs are the main threat, targeting young shoots in spring before the plant hardens. Powdery mildew can appear in dry summers. Aphids occasionally colonise soft growth. This tall perennial is otherwise very resilient; good soil moisture and airflow prevent most issues.

Young emerging shoots eaten or severed at ground level in spring; irregular holes in the delicate, glaucous foliage. Apply ferric phosphate pellets around crowns as growth emerges in spring. Copper barriers on pots. Encourage frogs and hedgehogs. Hand-pick after dark on damp evenings.

White powdery coating on leaf surfaces, mostly in late summer during prolonged dry spells; can cause early leaf drop. Water plants at the base during dry spells; improve air circulation by thinning surrounding growth. Remove and bin infected leaves in autumn. A diluted sodium bicarbonate spray offers organic suppression.

Colonies on soft shoot tips cause mild leaf curl; secondary damage from honeydew and sooty mould. Dislodge with a firm water jet. Insecticidal soap if populations are high. Plant nectar-rich companions to attract aphid predators.