Scoliopus and other western plants
Laura & Dave (Sat, 31 Jan 2004 01:09:14 PST)

Hi all
I've been following the thread on Scoliopus with interest, since I
was sent about a hundred seeds last spring through the kindness of a
fellow plant enthusiast in San Francisco. I don't know whether to
expect to see them this year or, like Trillium, next spring. But I sure
hope to be able to grow them on when they do show.
I've only seen them growing in the wild once, and that was in the
Mount Tamalpais (CA) watershed as I was driving through late on January.
They were in full bloom, but I only spotted them because of their
location. They were growing along the course of a small, possibly
vernal, creek in a shallow, gently sloped valley. Most of them were
coming up through a dense mat of moss, but the ones I noticed were
growing from the shoulder of the road where it crossed the stream. The
shoulder appeared to have been freshly graded the previous fall. The
plants were growing in pretty much straight fine sand. Mary Sue
recently wrote, "... in the Mendocino County flora one of the authors
had written that this plant had done well in her sandy San Francisco
garden...".
What this points out may be the key to growing many of the
Northwestern spring/summer ephemeral species, such as Trillium,
Erythronium, Clintonia, Lilium and Scoliopus. In our coniferous and
mixed forests, much of our soil is often two layered, with a dense
organic layer on top of a sand/gravel substrate. I've spent a bunch of
time doing plant rescues, and have found that the bulbs/tubers/rhizomes
of the various plants live under the organic layer, a bit into the
substrate. This make sense, as the contractile roots of many species
can pull the young plants down through organic matter, but have a
tougher go of it through sand/gravel, especially as the size of the
plant increases with age. Because of the ample fall/winter/spring rain,
nutrients have no problem migrating down to the roots, as decomposition
makes them available. Growth of mature bulbs/rhizomes is largely
horizontal. In our dry summers, the soil often dries completely; the
organic layer shrinks and separates from the substrate, supported by the
courser, undecayed twigs and branches. This creates an air space
between the layers (I've seen up to an inch) throughout the forest. The
early fall rains do little to rehydrate the organic layer, or the soil
beneath; it takes the hard, constant rains of late fall and winter to
accomplish this.
Where this is all leading is to the idea of soil layering in
gardens and containers, keeping the decaying organic material away from
the dormant plants. I've been experimenting with native plants in
containers, using a poor soil with good drainage in most of the pot, and
a top dressing of mostly composted organic material. In the few years
I've been trying this, Trilliums, Erythroniums, Lilies and others have
responded well.
I'm sorry if this is a bit(?) long winded, but I've read both on
this forum and Trillium_L how people have had trouble with western
species. The desire of finding the "right" soil mix is often mentioned,
but may, in my opinion, be a futile search, or a compromise at best. The
lack of layers could also explain why some people on this forum
mentioned they have trouble growing some species, even if they live
within the species native habitat. Thanks for letting me air these
ideas. I'd welcome any comments.

Peace and good gardening

Dave Brastow - Tumwater, WA (zone 7A)