Rhododendron 'Fastuosum Flore Pleno' problems — and how to fix them

Yellow leaves with green veins signal overly alkaline soil; apply chelated iron and acidify with sulphur.

Brown, shrivelled buds that fail to open are caused by leafhopper-spread fungus; control leafhoppers and remove affected buds.

Notched leaf margins indicate adult feeding; use nematode soil drenches in late summer to target larvae before they damage roots.

Botrytis fungus turns flowers brown in wet weather; good air circulation and removing infected material reduces spread.

Phytophthora root rot causes sudden wilting and dieback in waterlogged soils; plant on a slight mound to ensure drainage.