mulching (was Nemancur)
The best TB rhizomes I have ever seen were growing in a black soil derived
from the muck of a drained bog in central Ohio! The soil had been heavily
amended with limestone to adjust the pH. I think that like all plants, TBs
do well in soils of a moderately balanced fertility, which is what you get
when you use organic matter. Another excellent soi for TBs appears to be
sandy loam derived from river flooding.
Adding organic matter to clay gives it a better texture and indeed improves
the drainage. Paradoxically, organic matter also improves sandy soil, but
for the opposite reason--it gives it "body" that helps it hold water.
However, the drainage--in the sense that the spaces between particles are
not filled with water--is still good. Each little bit of OM acts like a
tiny sponge, holding water and releasing it slowly to plant roots.
I'm not sure why most bulbous irises don't like OM in the soil but it
probably has to do with what they adapted to in their native environments
(generally pretty lean pickings). Is Alan McMurtrie on this list?
Perhaps Sharon will jump in and give us her experience with arils and OM.
Best wishes, Bill
William A. Shear
Department of Biology
Hampden-Sydney VA 23943 USA
phone (804) 223-6172
FAX (804) 223-6374