The primary issue appears to be leaf scorch, which can happen if the water supply is inadequate. Since these were recently planted in March, their root systems are not fully established (which can impair water uptake). And, also now with the high heat, that adds stress on new plants that are getting established. Have you been watering regularly and deeply? It can take new shrubs up to two years or so to get fully established. The most important thing is to keep up with regular watering now (but also be careful not to over-water). The best way to do this is to feel the soil with your hand (a few inches down in the root zone) to determine if the soil is dry to the touch. When it feels that it's getting dry, it is time to water again. Hydrangeas are a type of shrub that is more sensitive to watering needs.

The mulch will help retain soil moisture; just make sure it is not placed directly against the trunks or stems.


Watering Trees and Shrubs

Christa