Mid-South Gardening: Will trade for dirt!, 1 by Pistil

Pistil wrote:
I have sprouted some Sourwood trees. I live in Seattle. They are not native here, and although they will grow they are slow and never get very big. I think it might be that they lack their symbiotic mycorrhizae. I would like to trade for a box of soil, freshly dug from under a native Sourwood tree, to include surface feeder roots that should have the proper breed of mycorrhizae. When I pot up my tiny seedlings I would mix the soil into the commercial sterile stuff. My little experiment.
I haven't put much in my tradeslist, but I have a lot of plants and houseplants, and some are unusual or expensive (Bartzella Peony, Mighty Chestnut Daylilly). The Sourwoods here are flowering, so it should be fairly easy to find one if you recall where you saw their brilliant fall foliage last year.
Any takers?