Strange Rhododendron

[Waffle Stomper]

I saw this unusual rhododendron on the Salmon Butte trail there were only a few bushes like these. Instead of some of the leaves turning yellow like most of them these had pink leaves. I've never seen anything like that before. I wonder if this is a different species or just a genetic mutation?

[Jabali]

I've seen this before on pacific rhododendron - sometimes most of the plants in an area have it. Sometimes there is less pink and more pale yellow, not the deeper yellow of dying leaves - and this discoloration is on this years leaves, not old ones which yellow and drop as a normal part of the plant's life process. Also notice the flecks of green on some leaves in the lower left. Something is interfering with the production of chlorophyll on these plants - and did an incomplete job on those leaves with patches left. Possibly a fungus disease as they are more active with the cooler weather this year. Any plant pathologists around?

[Waffle Stomper]

I was thinking about other possibilities too and noticed the younger leaves. The one thing I noticed this year was that there was very little sign of future or past blooms on these rhododendrons unlike the prolific blooms elsewhere. On a previous hike I noticed that so many of the leaves had a lot of creases in them. They seemed more stressed than other locations possibly interfering with the chlorophyll production as you suggested.

My curiosity has gotten the best of me, and I dropped a note to OSU to see if they will do me the favor of a reply.

[Waffle Stomper]

Good job Jabali. Your instincts are correct. I just received a reply from the Rhododendon Species Botantical Garden in Federal Way, WA. Here is their answer --

"The unusual leaves you saw on the plants of our native rhododendron have been infected by a fungus. It is the same fungus that causes azalea leaf gall, although in the evergreen rhododendrons the appearance is quite different. The leaves are generally the same shape as their uninfected counterparts but the chlorophyll is gone which causes the whitish-pinkish coloration and also allows the sun the burn the foliage much more easily whereas in azaleas the leaves become much more distorted, i.e., exceedingly thickened and swollen, then later a white layer of fungi coat the outside preparing to send forth new spores. Generally, the infection caused by this fungal species is not too detrimental to the plant, but is more of an aesthetic issue.

I hope this helps to answer you question. Thanks for your inquiry!

Rick

Rick Peterson
Rhododendron Species Botanical Garden
[email protected]
Phone: 253-838-4646
FAX: 253-838-4686"