Hydrangea stem rot
There are 3 common causes, and they need completely different responses — so working out which one you have matters more than treating quickly.
2 of them can kill the plant. Rule those out first.
Check these two things first
- Push a finger into the soil, two knuckles deep. Wet soil plus a wilting plant means too much water, not too little — and it is the commonest reason a plant is dying. Dry soil plus crisp leaves means the opposite. The leaves look nearly identical either way, so the soil is what tells you.
- Turn a damaged leaf over. Half of all diagnoses live on the underside: fuzz means downy mildew, fine webbing means spider mites, clusters of insects mean aphids. Nothing on the top of a leaf is as informative.
Most garden problems are cosmetic and resolve without treatment. Reach for a spray last, not first.
The 3 causes, and how to tell them apart
1.Overwatering
Act nowGrowing conditions
Yellowing lower leaves that feel soft rather than crisp, often falling while still yellow. The plant wilts despite obviously damp soil. Stems may go soft and translucent at the base, and the soil surface may develop a green or white film.
How to know it is this one
Wilting while the soil is wet. This combination is the whole diagnosis.
2.Root Rot
Act nowFungal disease
Above ground, yellowing and wilting that looks like drought but does not respond to water. Below ground, roots that are brown or black, soft, and smell sour — healthy roots are firm and pale, and the outer sheath of a rotted root slides off leaving a thread.
How to know it is this one
Wilting that does not improve after watering, and often gets worse.
3.Grey Mould (Botrytis)
TreatableFungal disease
A soft, dusty grey-brown fuzz that puffs into a cloud of spores when disturbed. It colonises dead or damaged tissue first — spent flowers, pruning wounds, bruised fruit — then moves into healthy tissue beside it.
How to know it is this one
Grey fuzzy growth that releases a visible puff of spores when touched.
Still not sure?
The diagnostic key adds two more questions — which part is affected and where the trouble started — and those usually settle it.
Run the diagnostic key