Hydrangea Flowering Issue - Ask Extension
Most of my hydrangeas are not flowering correctly. Only a few of the flower pedals on each head will open. What could cause this?
Knowledgebase
Hydrangea Flowering Issue #876105
Asked July 06, 2024, 1:34 PM EDT
Most of my hydrangeas are not flowering correctly. Only a few of the flower pedals on each head will open. What could cause this?
Wayne County Michigan
Expert Response
Hi Matt -
What I see here are some hydrangea arborescens. Originally, the wild hydrangeas were "lace caps", which is what I see you have here. Due to a natural mutation, an h. arborescens was discovered to have "mophead" flowers some years ago. So now, after much breeding, hydrangea arborescens can have either lace cap type flowers, or mophead type flowers. I've never heard of one having both! I am guessing that there is some genetic regression going on, if you formerly had mophead flowers and now you have lacecaps. I can't find any information available to me about that. However, I do see that lacecaps draw many more pollinators than the mophead type of flowers.
I would be sure that your culture for your plants is correct, and they are getting enough water right now. I have a couple of links here that might help you.
https://extension.illinois.edu/blogs/garden-scoop/2022-05-14-native-hydrangea-trial-evaluates-pollinator-value-and-landscape
https://ag.umass.edu/landscape/fact-sheets/growing-hydrangeas
I hope this helps you.
What I see here are some hydrangea arborescens. Originally, the wild hydrangeas were "lace caps", which is what I see you have here. Due to a natural mutation, an h. arborescens was discovered to have "mophead" flowers some years ago. So now, after much breeding, hydrangea arborescens can have either lace cap type flowers, or mophead type flowers. I've never heard of one having both! I am guessing that there is some genetic regression going on, if you formerly had mophead flowers and now you have lacecaps. I can't find any information available to me about that. However, I do see that lacecaps draw many more pollinators than the mophead type of flowers.
I would be sure that your culture for your plants is correct, and they are getting enough water right now. I have a couple of links here that might help you.
https://extension.illinois.edu/blogs/garden-scoop/2022-05-14-native-hydrangea-trial-evaluates-pollinator-value-and-landscape
https://ag.umass.edu/landscape/fact-sheets/growing-hydrangeas
I hope this helps you.
