Fall is a good time to have soil tested so that you can determine if fertilizer is even needed. If it is, early spring is the best time in most climates, followed by another small dose after bloom. Compost is often too alkaline and too high in nitrogen to be good for rhododendrons and azaleas at any time. Adding mulch in the form of conifer needles or bark or another suitable material is a good thing to do in the fall as it will insulate the soil in the winter and break down slowly.

Miketann, since you live in Seattle, you may be familiar with the Rhododendron Species Foundation in nearby Federal Way. They planted all of their plants in soil enriched with wood chips. The wood chips turned the soil into an unhealthy slimy mess. Most plants had to be replanted into a bark-soil mix. Watch your soil carefully to make sure you don't end up with the same problem.

Good advice, rhodyman!

I keep the woodchip soil ratio low enough for that not to happen. As we know, a good root environment is the key to success in growing rhododendrons. Woodchips alone doesn't have enough body for the long term. Almost all of my land is sloping, so good drainage is the norm, even where the soil is heavy.

I'm very familiar with the Rhododendron Species Foundation. I go to a lot of their plant sales. It's not far from where I live, Maple Valley, maybe 20 minutes.

Mike

My impression has always been that the now-infamous problems experienced at the RSF garden had to do with the use of massive amounts of sawdust , not wood chips. The whole episode is pretty thoroughly covered in David Leach's Rhododendrons of the World, among other places. Even very coarse sawdust and, indeed, wood chips, consist of mostly sapwood. Incorporated directly into the soil, as was the case at the RSF garden, both break down very quickly into an overly wet and sour mess. Bark, on the other hand, breaks down very slowly because of its high lignin content. Used as a mulch, there would seem to be little danger in wood chips. For incorporation or the creation of container mixes, sapwood should be avoided entirely and bark used instead.

I've never heard of this episode but it illustrates, broadly, what I'm always saying about cultivating plants as close to "real life" as possible. Obviously in the mountains of China, there is no natural process converting lumber into shaved lumber, and then tilling it into the soil. If anything, a trunk falls, and over a few years is converted into other life forms which then finally fall onto the forest floor. (Likewise there is no process that dumps 5-10-5 fertilizer on them every spring)

Knock on wood but so far my rhodies are growing very well on the areas - in a climate that is ultimately marginal in some ways and through hellish summers with combinations of heat waves, droughts, and floods - where I tilled in turface and permatil; in my opinion those made my soils more similar to, not less similar to, rocky, open mountain soils. The ability to remain aerated is clearly of primary importance. I'm so glad that I was very sparing with my addition of peat moss, I was hemming and hawing about that at the time, but there's been absolutely no sign that moisture retention wasn't adequate.

Mainegrower I have a private question for you. Have you deliberately set up your houzz profile not to have a message/contact link? Some people's do, some don't. If you prefer not to be contacted, fine, I can understand that. Otherwise, maybe you can see how to turn that feature on in your profile?

Update: I figured it out. You have to go to this URL: https://www.houzz.com/settingsAdvanced

And say "allow anyone to contact me". I've done that now to mine, so, you can send me a message at your convenience.

davidrt28: I have enabled the link and I will see how it goes. I am not finding the feature - establishing private contact with you, for example - at all easy to use.

Apparently I have to follow you, for you to message me. Check my profile again to see if you see the "Message" button up on the header image of an Arum italicum.

Finally! message was sent. No hurry to get back to me.

I remember the massive amounts of sawdust. Probably had something to do with the association with Weyerhauser timber company.

The only sawdust I deal with is what comes with the woodchips, not very much percentage wise.

Mike

I found this article if anyone is curious to read further about this situation:

http://scholar.lib.vt.edu/ejournals/JARS/v52n3/v52n3-hootman.htm

That's a good article and pretty well sums it up. Thank you, Davidrt28.

I need to tour the gardens, it's been awhile. The sales are held in a Weyerhauser parking lot.

Mike

This is interesting.

I have shied away from wood chips for decades, but it looks like a little is not only okay but perhaps even good.

Which reminds me...

Here at the moment the catkins are falling - or have fallen - from the oaks. They have gathered in the gutters in the odd street, and I was investigating them the other day, as you do, to ascertain their suitability for mulch.

What are people's opinions on this? (Not on my behaviour, but on whether the stuff is good, pH-wise.)

And oak leaves are good mulch for acid lovers, yes?

Late winter is the best period in my opinion :)