Aril Society International

Jane McGary
Wed, 21 Jun 2006 10:31:19 PDT
Mary Sue asked
>How much winter rainfall can these [aril] irises tolerate?

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 

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

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