[pbs] Bulb requirements - was Ixiolirion
Jane McGary
janemcgary at earthlink.net
Thu Jun 26 14:28:42 EDT 2008
Several interesting topics have come up here. First, good to hear from Yuri
Pirogov near Moscow, who observes that his collected Ixiolirion have done
better in his severe-winter climate than have Dutch imports of the same
species. This should encourage us to try to obtain wild-collected seed of
I. tataricum (I think there is at least one other species?) and try raising
it ourselves.
Second, Jim McKenney wrote that he believes his native soil, acid clay, is
not good for many bulbs. In fact being lodged in damp clay in summer might
be bad for them, but I don't think acidity itself would be a problem for
most species. I grow hundreds of bulbous species that come from areas with
alkaline soil, and I grow them in a slightly acidic but very well drained
medium. I've rarely bothered to add lime to my growing mix. A very good
gardener once told me that he thought almost no plant requires lime as long
as it is provided with enough fertilizer, although, on the other hand, some
plants (including many ericaceous ones) don't grow well in an alkaline
soil. There is widespread thought that plants endemic to ultramafic
(serpentine) soils do not require serpentine, either, and certainly I grow
a number of serpentine endemics without making any adjustment to the soil;
the theory is that these plants tolerate, but do not require, an ultramafic
substrate, and benefit from the lack of competition where plants that can't
tolerate it are excluded.
Moreover, when you visit limestone ranges, especially in the far North,
you'll see many ericaceous plants and other "lime-haters" growing in
organic deposits over the limestone.
Older books on growing alpines, especially, offer numerous recipes for
potting mixes, with elaborate lists of the particular plants to be grown in
each, but not many of us follow these rules nowadays. I do have a peat bed
in the rock garden, but it's primarily for moisture retention in summer,
and in it several terrestrial orchids usually seen in limestone areas are
flourisihing.
Jane McGary
Northwestern Oregon, USA
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