Solomon's seal is one of the most elegant plants for shaded and woodland gardens — the arching stems hung with paired, pendulous white-tipped bells appear reliably in spring and require almost no attention. The tips push through the soil around April and unfurl into the characteristic arching form within weeks.
Botrytis (grey mould)
Grey fuzzy mould on petals and stems, worst in cool wet conditions.
Remove affected parts immediately. Improve air circulation. Avoid overhead watering. Apply copper fungicide if severe.
Rust
Orange to brown raised pustules on the undersides of leaves, with yellow spotting on the upper surface. Heavy infections cause leaves to yellow and drop.
Remove and destroy infected leaves. Avoid overhead watering and improve air circulation. Apply a sulfur or copper-based fungicide if it spreads. Clear plant debris in fall.
Fungal leaf spot
Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.
Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.
Solomon's Seal Sawfly
Phymatocera aterrima →Grey-white larvae with dark heads feed on leaf undersides, stripping foliage to bare midribs and leaving stems skeletonized by midsummer.
Inspect leaf undersides from late spring and remove larvae by hand. Knock larvae into soapy water or apply spinosad if infestation is heavy. Plants usually recover the following year even after full defoliation.