Bulb requirements - was Ixiolirion

Jane McGary janemcgary@earthlink.net
Thu, 26 Jun 2008 11:28:42 PDT
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 

Jane McGary
Northwestern Oregon, USA

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