Unusual leaf formation on hydrangeas - Ask Extension
Both my Limelight hydrangeas and BoBo hydrangeas have unusual leaf clusters instead of flowers throughout the plants. We have treated the lawn with he...
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Unusual leaf formation on hydrangeas #876947
Asked July 12, 2024, 10:37 AM EDT
Both my Limelight hydrangeas and BoBo hydrangeas have unusual leaf clusters instead of flowers throughout the plants. We have treated the lawn with herbicides. The plants are in different locations in the yard , not near each other. Aside from these unusual clusters, the plants appear healthy and still have some blooms. I am hoping it is herbicide damage but am worried it is asters yellow. How do you tell the difference? These plants are 6 years old now and line the property. Would hate to loose them all.
Chester County Pennsylvania
Expert Response
Good morning, and thank you for your question. Piedmont Master Gardeners handled a question about asters yellow, and I'm including some of the information here so that you may determine if that's what is affecting your plant. From your photos, asters yellow doesn't appear to be the problem, so please read further after you've taken a look at this:
These products can cause injury when applied inappropriately, when they turn into a gas (a process called volatilization), or when they are blown by the wind away from the targeted area (a process called drift). Accurately diagnosing plants that show herbicide injury symptoms is often difficult since, in many cases, other causes may be involved or it may be uncertain what herbicides were applied. Trained or experienced individuals may be able to tell if a specific herbicide injured a plant. These professionals often examine the plant symptoms and background information (including the type of herbicides used, application rates and timing, injury patterns, and the plant species affected) to confirm or discount the possibility of herbicide injury. Using chemical analysis to find the cause of herbicide injury only works when the chemical is still present at detectable levels in live plant tissues or adjacent soil.
Post-emergence broadleaf herbicides selectively kill actively growing broadleaf plants. This includes growth regulator herbicides that have active ingredients such as 2,4-D; 2,4-DP; MCPA; MCPP; dicamba; and others. Herbicides in this group are labeled for use in a number of different locations including homes, farms, and industry. These herbicides are quite prone to drift and volatilization. Injury symptoms include:
Twisted leaves, Downward cupping on leaves, Narrow, strap-like leaves on the youngest growth.
Please consider sending a sample of the distorted leaves to the Penn State Extension Plant Clinic for analysis. Visit the site at <personal data hidden>, and you'll find detailed instructions for collecting and mailing. It's free of charge to Pennsylvania residents. I hope it provides the information you need to help your beautiful hydrangeas.
Jeanne
- Small, distorted flowers that remain green and don’t develop the proper color for the species.
- Green tufts of deformed leaves embedded in the flowerhead itself. This is a condition known as phyllody, which is a reversion of flowers to a leaflike form.
- Flower petals may appear as a ring of tiny greenish-yellow spoons arrayed around the base of highly deformed cones.
- Cones may appear as tightly clustered rosettes.
- Excess growth may appear at the tops or sides of flowers.
- Yellowed (chlorotic) leaves with veins that remain green.
- Twisted or curled foliage.
- Stunted plant growth, particularly on younger plants.
- Abnormally bushy growth.
- Flowers may not produce seeds.
These products can cause injury when applied inappropriately, when they turn into a gas (a process called volatilization), or when they are blown by the wind away from the targeted area (a process called drift). Accurately diagnosing plants that show herbicide injury symptoms is often difficult since, in many cases, other causes may be involved or it may be uncertain what herbicides were applied. Trained or experienced individuals may be able to tell if a specific herbicide injured a plant. These professionals often examine the plant symptoms and background information (including the type of herbicides used, application rates and timing, injury patterns, and the plant species affected) to confirm or discount the possibility of herbicide injury. Using chemical analysis to find the cause of herbicide injury only works when the chemical is still present at detectable levels in live plant tissues or adjacent soil.
Post-emergence broadleaf herbicides selectively kill actively growing broadleaf plants. This includes growth regulator herbicides that have active ingredients such as 2,4-D; 2,4-DP; MCPA; MCPP; dicamba; and others. Herbicides in this group are labeled for use in a number of different locations including homes, farms, and industry. These herbicides are quite prone to drift and volatilization. Injury symptoms include:
Twisted leaves, Downward cupping on leaves, Narrow, strap-like leaves on the youngest growth.
Please consider sending a sample of the distorted leaves to the Penn State Extension Plant Clinic for analysis. Visit the site at <personal data hidden>, and you'll find detailed instructions for collecting and mailing. It's free of charge to Pennsylvania residents. I hope it provides the information you need to help your beautiful hydrangeas.
Jeanne
