Hi Michelle,

Thank you for your question. 

It appears your hydrangeas are likely experiencing a combination of transplant shock and heat stress. Hydrangeas are particularly susceptible to stress because they need lots of water to cool themselves, and transplanting in early September followed by hot weather has put additional strain on their root systems [², ³]. The brown tops you're seeing are likely heat and drought damage, where the plant tissue couldn't get enough water fast enough [⁴].

Continue your current care:
Gertens gave you good advice - keep soaking the roots daily and maintain mulch around the base [¹]. The mulch will help retain soil moisture, which is crucial for recovery.

Additional steps to help them survive:

1. Deep watering technique: Instead of frequent shallow watering, focus on deep watering using a soaker hose or watering slowly at the base of the plant. This ensures water penetrates deeper into the soil to reach the entire root zone [⁴].

   
   

2. Avoid pruning: Resist the urge to prune the brown, damaged portions right now. Pruning will cause new tender growth that's vulnerable to further heat damage [⁴]. Wait until next spring to prune any dead branches [³].

   
   

3. No fertilizing: Avoid fertilizing until next spring, as excess fertilizer can attract pests and stress the plants further [², ⁴].

   
   

4. Monitor for pests: Watch for spider mites, which can become problematic when hydrangeas are stressed from heat and drought [⁴].

Learn More: 1. extension.oregonstate.edu, 2. ask.extension.org, 3. ask.extension.org, 4. extension.oregonstate.edu