dwarf hydrangea leaves curling - Ask Extension
I have 2 dwarf hydrangeas that are approximate 4 years old; 1 is normal in appearance and the other (approx 24" apart) has had its leaves curling. Â...
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dwarf hydrangea leaves curling #872122
Asked June 07, 2024, 4:51 PM EDT
I have 2 dwarf hydrangeas that are approximate 4 years old; 1 is normal in appearance and the other (approx 24" apart) has had its leaves curling.  Both get same amount of sunlight and water. I thought there was perhaps a pest so I trimmed all the curled leaves but didn't see any evidence of bugs.  A week later further leaves have started curling that were flat last week.  Any suggestions for cause & cure?  Thank you!
Multnomah County Oregon
Expert Response
Hi Michelle and thanks for your question and pictures of your hydrangea with curling leaves. When I enlarge the picture I can see signs of a very tiny insect so I suspect thrips which can be taken care of with a strong spray of water or insecticidal soap.
There is some stressor to the affected plant that is not there for the healthy plant, so it would be good to figure out what IS different between the two. Did you fertilize one more? Does it have more (or less) mulch around the base? Did it get more (or less) rain somehow? Could the problem plant have been exposed to a chemical?
There are some natural predators that will take care of thrips, so you don't have to keep spraying once the population is under control. I'll attach an article about them to get you up to speed, and if you have a hand lens or magnifying glass, unroll the edge of a curled leaf and look for the tiny, tiny insects.
https://pnwhandbooks.org/insect/hort/landscape/common/landscape-thrips
Best of luck in controlling them,
There is some stressor to the affected plant that is not there for the healthy plant, so it would be good to figure out what IS different between the two. Did you fertilize one more? Does it have more (or less) mulch around the base? Did it get more (or less) rain somehow? Could the problem plant have been exposed to a chemical?
There are some natural predators that will take care of thrips, so you don't have to keep spraying once the population is under control. I'll attach an article about them to get you up to speed, and if you have a hand lens or magnifying glass, unroll the edge of a curled leaf and look for the tiny, tiny insects.
https://pnwhandbooks.org/insect/hort/landscape/common/landscape-thrips
Best of luck in controlling them,
