Half bloomed hydrangeas

(Question)

Help, my Annabelle hydrangeas are only half blooming…its mid July…any chance they will fully open? Anything I can do? The bush beside it is blooming fine. Here are photos. THANK YOU.

(Answer)

Annabelle hydrangea typically flowers from June to September. Due to the cool spring this year, plant growth has been set back a few weeks, so it is still possible that your hydrangea will fully bloom.

From your email, I assume that this plant has fully bloomed in previous years. If not, there could be a problem with the quality of the plant itself.

The plant could be beginning to revert back to its wild form. This phenomenon while uncommon can occur particularly if the plant came from a “wild” source.  This is discussed in more detail here: https://web.extension.illinois.edu/askextension/thisQuestion.cfm?QuestionID=24686&catID=34&AskSiteID=34

Please investigate these other possible reasons the flowers are not fully blooming:

  • growth of adjacent plants is reducing the sun, or amount of water this hydrangea is receiving.
  • The plant is subject to some type of pest or disease

Continue to watch over the next few weeks and let us know if you uncover any other problem.