WSU Extension

Hortsense

Hydrangea
 
Disease
Failure to bloom 
Fungal leaf spots 
Hail damage 
Herbicide damage 
Leaf scorch 
Marginal leaf necrosis 
Powdery mildew 



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Caption:
Photo by: J. Glass
  
Hydrangea : Leaf scorch
(revision date: 4/23/2014)


Biology
Leaf scorch on hydrangea is a common physiological problem. Typical symptoms include yellowing leaves, or irregular dry, brown blotches. Leaf tips and margins may turn brown, as well. Severely damaged leaves may drop from the plant. Leaf scorch results when the leaves lose water faster than it can be supplied by the roots, so wilting may occur before scorch is noticed. Common causes include inadequate watering, exposure to strong light (sunlight or reflected light), high temperatures, or dry, windy conditions. Scorch can also occur as a result of damaged roots or stems, such as from an injury, compacted soils, or overwatering or overfertilization. Leaf scorch is most common on leaves farthest from the roots and those most exposed to harsh conditions--often the top of the plant and the sunniest side are most affected. Occasional minor damage is primarily an aesthetic concern, but severe or recurring damage may indicate an underlying problem with the plant's health or planting location.
Management Options


Non-Chemical Management
  • Provide adequate water for plants, particularly those planted in sunny or windy locations.
  • Fertilize moderately to avoid root damage.
  • Light summer pruning will help reduce the water needs of the plant, but may also reduce flowering. This will not resolve the underlying cause of the damage, but may help maintain plant health in the short term.
  • When practical, consider moving those plants that routinely suffer from leaf scorch.
  • Plant hydrangeas in appropriate locations. Most prefer dappled shade, especially during the hottest part of the day. Plants near reflective surfaces such as walls and fences may be more susceptible to leaf scorch.
  • Apply an organic mulch over the root zone to help maintain soil moisture.
  • Improve drainage or plant on a berm in areas with poor drainage and a high water table.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images

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Caption:
Photo by: J. Glass