Brown spots on Hydrangea flowers
The brown spots on hydrangea flowers not only look ugly, they also signal that something is wrong with the plant. In order to quickly help hydrangea and enjoy its beautiful flowers again, it is worth finding out what causes the discoloration of the flowers.
Brown spots on hydrangea flowers – fungal diseases
The numerous tiny brown spots on hydrangea flowers are a symptom of gray mold. This disease is caused by the fungus Botrytis cinerea, and its development is favored by frequent rainfall, strong shading and plant density.
The symptoms of gray mold can also be seen on the leaves and shoots of hydrangeas, as brown-brown and watery spots that grow rapidly and become covered with a gray, dusty coating. As a consequence, the flowers, buds, leaves and tops of the hydrangea shoots gradually turn black and die.
Another cause of brown spots on hydrangea flowers is anthracnose. The disease is caused by the fungus Colletotrichum gloeosporioides, which hibernates in dead leaves and infects hydrangeas in hot (23-32 ° C), rainy and foggy weather conditions.
The spots reach a large diameter and often cover the entire surface of the petals. Symptoms of anthracnose, in the form of irregular spots, are also visible on the leaves of the hydrangea.
To prevent gray mold and hydrangea anthracnosis, avoid thickening the bushes and soaking their leaves during watering. Plants are best watered early in the morning so that the wet parts of the shrubs have time to dry before the night. Sick flowers and hydrangea leaves must be removed, and when symptoms are severe, plant protection products must be used.
Brown spots on hydrangea flowers – heat stress
Brown spots on hydrangea flower petals can be caused by sunburn or drought. Hydrangea feels best in partial shade or in locations where sunlight is partially diffused. Only a few varieties of hydrangeas can tolerate strong sunlight.
In highly sunlit positions, hydrangea flowers can easily be burned, causing brown spots on the petals or complete browning and drying of the flowers. This type of damage can be prevented when planting hydrangeas in the garden.
For the cultivation of hydrangeas, it is best to choose positions with eastern or western exposure and under the canopy of tall trees, where they will be provided with shade during the hottest time of the day.
Hydrangeas growing in a very sunny place are best transplanted in a shaded place in early spring, and shade them in periods of sunny and hot weather.
