Native Plants
![](../_images/smarty_plants.gif)
Q. Who is Mr. Smarty Plants?
A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
![](../_images/mr_smarty_plants_logo_web_200w.jpg)
rate this answer
![](../_images/star_00.gif)
Friday - July 11, 2008
From: Portland, OR
Region: Northwest
Topic: Diseases and Disorders, Shrubs
Title: Leaf burn on hydrangeas
Answered by: Barbara Medford
QUESTION:
What causes my leaves to burn on my healthy hydrangeas?ANSWER:
Our first thought would be too much sunshine, as the hydrangea thrives best as an understory plant with dappled shade. However, in Portland that doesn't seem like a big danger. Hydrangeas are susceptible to sunscald, chlorosis in alkaline soils, and winter dieback. Many weak, brittle canes are easily broken in wind and ice. Forms colonies from a shallow root system. Canes can be cut to the ground every two or three years to keep the shrub smaller, but if the canes are allowed to grow, the naturally peeling bark is attractive. Pest free. Prune immediately after flowering. There are three hydrangeas native to North America, but they tend to be more in the southern United States and none are native to Oregon. If it appears that the plant is getting too much sun, give it extra water, making sure it is not standing on the roots, and try to arrange a little more shelter for the plants next summer.
If that doesn't appear to be the problem, look at this Alabama Cooperative Extension article on Diseases of Hydrangeas. There are good illustrations of each of the symptoms of the various diseases, as well as suggested treatments. And you can go to this Oregon State University Extension page and try to find out if other similar plants in your area are being similarly affected.
More Diseases and Disorders Questions
Is December a good time to prune oaks in Central Texas?
December 29, 2010 - Given that we haven't had much cold weather here in central Texas (Wimberley) this season, is it a good time to trim live and Spanish oak trees (damaged limbs and low hanging branches and suckers)? ...
view the full question and answer
Dead portions on oak tree in Hutchinson KS
August 22, 2011 - I have an oak tree on the property I just moved into. One tree is healthy, the other has a dead side or almost dead. It did have some new green leaves on the dead branches but not many. What should...
view the full question and answer
Mildew on phlox paniculata from Morrisville PA
May 30, 2014 - My Phlox paniculata, all 7, have powdery mildew. I read about using NEEM to combat the mildew. NEEM is organic but the bottle says it is also an insecticide. The phlox are near my milkweed and gold...
view the full question and answer
Problems with red oak trees in North Central Texas
July 13, 2013 - What is the disease effecting Red Oak trees in North Central Texas; causing them to lose leafs in Spring/Summer and turning the remaining leaves light yellow/lime green in color.
Thank you.
view the full question and answer
Recovery of water-stressed Agarita
August 11, 2014 - Hello! I planted a small agarita at the end of May and then
left town for six weeks. During that time it was supposed to receive weekly deep irrigations to help it establish, but it seems that som...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |