Hello! The symptoms are similar to those caused by physiological stress: strong solar radiation in correlation with high temperatures and dry wind, a phenomenon called “leaf scorch”. It is well known that hydrangea prefers a partially shaded location, not a sunny area.
The damaged vegetative parts can be removed by pruning, with well sharpened and disinfected tools (e.g. ).
Additionally, it is recommended to remove the layer of decorative bark/decorative stones (i.e. foil, if applicable) at the base of the hydrangeas, as the materials placed at the base of the plants maintain a high and constant humidity at ground level, thus creating a favorable environment for the development and propagation of plant pathogens. In the future, it is advisable to keep a permanently aerated area around the hydrangeas. Since the activity and spread of plant pathogens is stimulated by the high and constant soil humidity.
Starting in spring, you can consider applying fertilizers such as (a natural fertilizer that contributes to improving soil quality, supports root development, increasing the plant’s resistance to stress factors – to be applied by watering) and Hortensia (a fertilizer specially formulated for the nutritional requirements of this plant species – to be applied by foliar spraying).
More information about the care of this plant species can be found in our article: Hortensia, planting guide and care work.