rosemary aging decline

Symptoms

Bare woody base, growth only at branch tips.

Easily confused with

• grey mould (Botrytis)

  How to tell them apart: On rosemary, Botrytis cinerea (grey mould) produces soft, water-soaked brown lesions on shoots and foliage that collapse and rot, and in damp, crowded bushes a tell-tale fuzzy grey-brown velvety mould forms on the dead tissue, often spreading downward from cut or wounded tips. Abiotic woody decline instead shows dry, firm dieback with no fungal growth at all: the wood turns grey-brown and brittle, foliage greys and stays attached, and the pattern follows stress lines such as the bare aging centre/base, a waterlogged root zone, or cold/drought-exposed sides. The decisive sign is the grey velvety sporulation of Botrytis after humid weather, which is completely absent in abiotic decline.

• overwatering / waterlogging

  How to tell them apart: Overwatering / waterlogging versus natural aging (woody) decline on thyme both look like a browning, thinning subshrub, but the soil and stem tissue tell them apart. Overwatering yellows the LOWER leaves first, leaves a SOFT, dark, mushy stem base with root-rot smell, keeps the soil constantly wet (often with fungus gnats), and harms even the young shoots. Aging woody decline instead leaves the lower stems DRY, hard and bare-brown (lignified, no softness or smell) in free-draining soil, with healthy green growth surviving only at the very branch TIPS, developing slowly over several years.