Rhododendron dying

darinvAugust 26, 2013

Long time reader first time poster...Hello!
Ok, the skinny is that I have a Rhododendron that is not doing well at all.
It has progressed worse since the picture.
Many of the branches are dying off. Only a fraction of the limbs have green leaves on them now.
It may be hard to see from the picture, but a lot of the limbs appear to be dead and the leaves have long since withered away. It's slowly claiming more and more of the plant.
I'm hoping the picture provides enough of a description, but I can definetly relay more info if needed.
Any help would be greatly appreciated.

Thank you for reporting this comment. Undo
akamainegrower

It's possible that a dry root ball is to blame. Was this rhododendron planted fairly recently? If so, digging it up and soaking the root ball may be all what's needed to save at least some of the plant.

Another possibility is so-called stem dieback. This is caused by a fungal infection from phytophthora cactorum. Hot weather and less than perfect drainage are contributing factors in this disease. I'm not aware of any recommended fungicide for this. The best you can do is trim back to live, green wood, rake up and dispose of any fallen leaves and hope for the best. Rhodyman's website may have some more detailed information.

    Bookmark   August 27, 2013 at 4:56AM
Thank you for reporting this comment. Undo
akamainegrower

Another possibility I forgot in my first post is boytryosphaeria canker, another fungal disease. This is probably more likely in a drought stressed rhododendron in the landscape than phytophthora. Advice remains the same. Check the rootball, dig up and soak if it is dry. Prune back to green wood. Pick up and dispose of fallen leave.

There are some fungicides available to home gardeners that may help, but they tend to be pretty nasty and expensive. There are one or two "green" fungicides on the market, but I have had no direct experience with them.

    Bookmark   August 28, 2013 at 5:00AM
Thank you for reporting this comment. Undo
darinv

I planted the rhododendron approx. 2 years ago, maybe 3.
Would it be too late to attempt the root soaking now?
I will definitely check out Rhodyman's website and weigh out the fungicides.
I just took this last photo a couple days ago.
You can see that it is still going downhill.
Thanks for the input!

    Bookmark   August 30, 2013 at 3:45PM
Thank you for reporting this comment. Undo
akamainegrower

It actually looks better in the more recent photograph. Leaves appear healthy and green even though there's a sizable patch of bare stems. What happens if you scrape away the bark on these stems? Can you see green cambium tissue anywhere? If you can, try trimming them back to that point. If the stems are clearly dead all the way to the base, cut them back to the bootom.

It does not seem terribly likely that a dry rootball would be the problem after 2-3 years, but possible if this has been a particularly dry summer. The leaves in the second photo do not suggest dryness at the root, either.

At this point, I'm not very confident in the fungal infection diagnosis, either. Could the patch of dead stems be the result of winter sun and wind exposure?

    Bookmark   August 31, 2013 at 5:15AM
Thank you for reporting this comment. Undo
rhodyman(SE PA, USDA Z6)

The die-back fungal infection and the brown leaf tips suggest a drought period in the past. The nice new green leaves indicate it is on its way to recovery. It may need watering in any future drought to prevent this happening again. Remove any diseased material such as dead leaves and dead stems. As aka mentioned, if the thin cambium layer immediately under the bark is not green, the branch is dead. Remove it and destroy it in the garbage or a fire. Do not compost it.

    Bookmark   August 31, 2013 at 10:09AM
Thank you for reporting this comment. Undo
rhodyman(SE PA, USDA Z6)

The die-back fungal infection and the brown leaf tips suggest a drought period in the past. The nice new green leaves indicate it is on its way to recovery. It may need watering in any future drought to prevent this happening again. Remove any diseased material such as dead leaves and dead stems. As aka mentioned, if the thin cambium layer immediately under the bark is not green, the branch is dead. Remove it and destroy it in the garbage or a fire. Do not compost it.

    Bookmark   September 4, 2013 at 3:57PM
Sign Up to comment
More Discussions
Yaks for Richmond, VA?
I am considering two Rhodies for a small, shaded, urban...
jupitertree
Double flower buds
Hi, I have both Haaga and Helsinki rhododendrons. They...
dee_can1
Please help me identify this azalea
When I purchase my house, it had a beautiful azalea...
mmp01
thoughts on permanent soil enhancement
This is more or less a followup to Mainegrower's questioning...
davidrt28 (zone 7)
Adjust pH for Azaleas
I have two azaleas in separate planters and they both...
cakbu
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™