The Value of Rotted Wood for Rhododendrons
by Jeannette Grossman
Some years ago when Mrs. A. C. U. Berry gave us our first rhododendrons, she also gave us a valuable tip on their culture. "Use rotted wood as a mulch," she said. "There is nothing better."
We not only use rotted wood as a mulch, but we work generous quantities of it into all planting holes where new rhododendrons are to go. Decaying stumps and fallen logs in our woodland provide a ready supply. But if it were not so handy, I would certainly look around until a supply was found.
Peat will pack and form a crust in dry weather, but rotted wood will remain loose and friable. It has a capacity to hold moisture unequaled by any other material. In spite of the hot, dry summer just past, our rhododendrons have needed little watering. A light sprinkling of their foliage after hot days was given.
The hybrids of williamsianum and campylocarpum, and all dwarf species are exposed to several hours of afternoon sun in our garden. With temperatures of 90 and above for many days this summer, I wondered if our plants could take it. While these varieties may be able to stand more sun than others, I believe the cool root-run provided by the rotted wood, kept them in good condition despite the extreme heat.
It is interesting to note that native plants in our woodland choose to grow in rotted wood instead of in soil. Large firs and vine maple send their roots along a fallen log for many yards. Other young trees and ferns are growing on top of old stumps. Since many rhododendrons are epiphytes, perhaps this may be the way to keep some of the more difficult species happy.
All ericaceous plants respond well to rotted wood. A mulch of it is applied to our collection of heathers each spring and again in late summer. Layers root easily too in this medium, and it keeps down weeds.
I do not know if there is any food value in rotted wood, but we have never found it necessary to fertilize any of our rhododendrons. They set plenty of bloom-buds and foliage is a good healthy green. But best of all, rotted wood costs nothing. It is free for the taking.