Hydrangea not blooming - Ask Extension
One of my hydrangeas is not blooming normally this year. Flowers are partially formed but not opened. Adjacent plant seems normal. Suggestions?
Knowledgebase
Hydrangea not blooming #876068
Asked July 05, 2024, 11:45 PM EDT
One of my hydrangeas is not blooming normally this year. Flowers are partially formed but not opened. Adjacent plant seems normal. Suggestions?
Larimer County Colorado
Expert Response
Hi John,
A couple thoughts...
1. Have any herbicides been used near the plant? Something that perhaps has 2,4-D? Because this could be a growth-inhibiting herbicide that has distorted the growth - and some of the leaves show cupping too.
2. It could be a virus. A couple possibilities are aster yellows or a carlavirus. If herbicides haven't been used - and the adjacent plants are normal - then a virus could be the culprit. Aster yellows are spread by leafhoppers and carlaviruses can be spread by aphids. The only way to confirm a virus would be to send samples to the CSU Plant Diagnostic Lab at Spur in Denver. Unfortunately, the problem with viruses is that it usually results in removing the plant.
If you do submit samples, you might call the lab first to ask how much testing will cost and how to best send your samples.
A couple thoughts...
1. Have any herbicides been used near the plant? Something that perhaps has 2,4-D? Because this could be a growth-inhibiting herbicide that has distorted the growth - and some of the leaves show cupping too.
2. It could be a virus. A couple possibilities are aster yellows or a carlavirus. If herbicides haven't been used - and the adjacent plants are normal - then a virus could be the culprit. Aster yellows are spread by leafhoppers and carlaviruses can be spread by aphids. The only way to confirm a virus would be to send samples to the CSU Plant Diagnostic Lab at Spur in Denver. Unfortunately, the problem with viruses is that it usually results in removing the plant.
If you do submit samples, you might call the lab first to ask how much testing will cost and how to best send your samples.
Hi Alison,
Thanks for the quick response.
We did use some roundup for a very small spot treatment near the plant early this spring. If that is the problem will the plant recover on its own? Should I be doing anything?
I will also contact the diagnostic lab to check into some testing. Assuming it isn’t too expensive I will probably go ahead and get a sample tested for a virus. If it is a virus how worried should I be about the other hydrangeas nearby? Is the virus spread easily?
Thanks,
John
Hi John,
This isn't glyphosate injury, so I'm leaning towards a potential virus.
Aster yellows are spread by leafhoppers, so yes, the other plants can be affected. Generally the course of action is to remove the one showing symptoms.
I found a very similar thread and photos from the Ask Extension system. It was in Minnesota: https://ask2.extension.org/kb/faq.php?id=488020
This isn't glyphosate injury, so I'm leaning towards a potential virus.
Aster yellows are spread by leafhoppers, so yes, the other plants can be affected. Generally the course of action is to remove the one showing symptoms.
I found a very similar thread and photos from the Ask Extension system. It was in Minnesota: https://ask2.extension.org/kb/faq.php?id=488020
