In a message dated 96-10-27 12:59:52 EST, you write:
Way back in October, Gary Sides wrote (quoting Blyth catalog, article by
>When transplanting bearded iris my own
>practice is to add superphosphate, which seems to ward off attacks of
>rhizome rot, and then to counteract any acidity in the soil, use a
>dressing of finely ground limestone (Agricultural Lime, 'I use
>pellitized') in winter. And he underscores: Otherwise in a limeless
>soil, bearded iris are apt to suffer from leaf spot."
Quite a few years ago, I got a catalog from Bernice Miller in Alabama, in
which she talked about how some bearded iris seem to need lime and others do
best under slightly acid conditions. Her experimental observation (as I
recall) was that iris bred in the naturally alkaline soils of the more arid
parts of the United States (mostly the southwest I think she said) need lime,
but those from the soggy east do better in more acid conditions.
I assume this fits in with what Clarence, Lloyd and others have said about
the species that have gone into making our modern tall bearded iris - some
(probably the two Mediterranean ones) need more lime.
I used to only fertilize with bonemeal and now and then some crushed
dolomitic limestone. I had less rot (maybe), but a lot less bloom - high
rainfall flushes nutrients out of my gravelly soil.
Linda Mann email@example.com east Tennessee USA