Native Plants

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Sunday - October 07, 2007

From: Austin, TX
Region: Southwest
Topic: Soils, Shrubs
Title: Potting soil recipe for azaleas
Answered by: Barbara Medford

QUESTION:

I have a couple of Azaleas in pots that need repotting.I can't remember the recipe for the medium I put them in last time other than pine bark mulch. I think there were three ingredients. What is your recommendation?

ANSWER:

Even Mr. Smarty Plants can learn something new. We thought something as exotic-looking as an azalea must surely be a sub-tropical non-native. But, a search in our Native Plant Database turned up 26 native varieties. Not that it has to be native to be grown in a pot, of course, but at the Lady Bird Johnson Wildflower Center we try to concentrate on the care and propagation of plants native to North America. Turns out that azaleas include not only natives to North America, but we found 3 native to Texas! Among the other things we learned is that all azaleas are rhododendrons but not all rhododendrons are azaleas. We learned that wild azaleas are found on every continent except Africa and South America, with Southwestern China and Papua New Guinea having the most species. They have been hybridized for hundreds of years, and in the U.S. the natives do best in the Pacific northwest where rainfall is plentiful and winter temperatures are not too low. For more information, go to this site on Care of Azaleas.

But that's not what you asked, was it? You wanted a recipe for potting soil for containerized azaleas. On the above-mentioned website, we finally found a recommended recipe. We don't know if this was the one you were thinking of, but we hope so. It calls for equal proportions of peat moss, vermiculite, potting soil and coarse sand.

And, since we found those Texas native azaleas, let us tell you about them. They are Rhododendron canescens (mountain azalea), Rhododendron oblongifolium (Texas azalea), and Rhododendron prinophyllum (early azalea), pictures below.

Rhododendron canescens

Rhododendron oblongifolium