Aril Society International
Jane McGary (Wed, 21 Jun 2006 10:31:19 PDT)

Mary Sue asked

I also live in a region with heavy and prolonged winter rains, often
lasting into June, and my experience is that Oncocyclus irises cannot
tolerate this climate even under the protection of the bulb frame. They
generally produce some foliage in late fall and this is very susceptible to
fungus and/or bacterial infection, which saps the plant's strength and
eventually kills it. I think you could grow them with a careful program of
spraying, but I don't want to go to that length. The mere moisture in the
atmosphere seems to promote these infections, even if no rain actually hits
them.

In contrast, hybrids between the Oncocyclus and Regelia sections (known as
"Regeliocyclus" or
"Oncogelia" hybrids) do extremely well in the bulb frame because they don't
produce leaves until early spring. Many of them have the same spectacular
marking and coloration as Onco irises. I haven't tried them in the open
garden, however.

Jane McGary
Northwestern Oregon, USA