Sucking plant pests
If your hydrangea gets yellowish and later brown leaves, the plant is often attacked by spider mites. The tiny insect pests are only about half a millimeter in size and can therefore hardly be seen with the naked eye. As a result, the infestation is usually only discovered when the extremely fine webs become visible.
- Brown spots on the Dieffenbachia foliage - what's going on?
- What size does the hydrangea reach?
- Hydrangea growth: how big and wide is the hydrangea?
Spray the plant with insecticides containing rapeseed oil and make sure that the undersides of the leaves are thoroughly wetted.
Brown leaves due to fungal attack
You can recognize leaf spot fungi by the brown spots on the middle of the leaf. The leaf tissue is initially thin and then tears open at the affected areas.
Remove all diseased plant parts and dispose of them with household waste. The infected leaves must never be put on the compost, as the fungi survive there. When applying the valuable fertilizer, you would unintentionally distribute the spores in the garden and encourage new infections. If the infestation is severe, spray the hydrangea with a suitable fungicide.
The hydrangea is one of the very thirsty plants. It reacts very sensitively to a lack of water, which is noticeable in the early stages by hanging flowers and leaves. If the plant is not watered enough, the leaves will dry out and turn brown.
Too much fertilizer can also lead to brownish discoloration of the leaves. The foliage of an over-fertilized hydrangea dries up from the edge and is then thrown off.
Tips & Tricks
Hydrangea pots offered in early spring are almost always used in the greenhouse and have been brought to bloom prematurely. As a result, the plants are susceptible to changes and often turn brown leaves as soon as they are moved into the field. So get these hydrangeas used to moving slowly.