If the hydrangea's foliage suddenly turns brown and dries up, this can have various causes. In addition to care errors, pests and plant diseases can also be responsible for this.
What are the causes of dry leaves on hydrangeas?
Dry, brown leaves on hydrangeas can be caused by spider mites, fungal infestation, sunburn or lack of water. Countermeasures include targeted watering, pest control, sunlight adaptation and fungal control.
Brown leaves due to spider mites
Spider mites are relatively common in warm and dry conditions. The arachnids are yellowish-green, orange or reddish-brown in color and are difficult to spot because of their small size of only about half a millimeter. The animals are usually only noticed when the leaves turn brown and finally dry out. The unmistakable sign of a spider mite infestation is the fine white web on the underside of the leaves.
Remedy
Treat Hydrangea several times with sprays containing rapeseed oil (€12.00 on Amazon). For houseplants, you should increase the humidity.
Fungi as a cause
If the entire leaf does not turn brown, but only shows numerous dry brown spots that tear open as it grows, the hydrangea is infected with leaf spot fungi. Poor nutrient supply and excessive humidity are usually responsible for the occurrence of the disease.
Remedy
Remove all diseased plant parts and dispose of them in household waste. Fertilize the hydrangea with a suitable fertilizer. In many cases, a chemical fungicide is necessary to prevent the fungus from spreading further.
Sunburn of the leaves
Hydrangeas grown in a greenhouse are not used to sunlight. If the plant is exposed to UV radiation too suddenly, the leaves will burn and dry out. Watering errors can also cause sunburn. If you water the hydrangea while the sun is shining on it, water droplets on the leaves act like burning glasses.
Remedy
- Hardenseas in pots slowly get used to the changed conditions outdoors.
- Always water plants in the morning or evening.
Leaf dryness due to lack of water
The Latin plant name “Hydrangea” means “water slurper” and symbolizes the enormous thirst that the plant can develop, especially on hot summer days. If you don't water enough, the hydrangea will initially let its leaves and flowers droop to reduce evaporation. If there is a continued lack of water, the leaves dry out and turn brown.
Remedy
Water the hydrangea thoroughly whenever the top few inches of soil feel dry. On very hot days it may be necessary to water the hydrangea in the morning and evening.
Tips & Tricks
With proper care and location selection, hydrangeas are less susceptible to diseases and pests. Plants that are well cared for usually recover quickly, so that the leaf damage can no longer be seen after a short time.