Scottish Rock Garden Club Forum

Specific Families and Genera => Iris => Topic started by: penstemon on November 30, 2014, 02:37:03 AM

Title: another oncocyclus question
Post by: penstemon on November 30, 2014, 02:37:03 AM
Now that I've learned to follow instructions, and the old seed I was given has started to germinate, I have a question about Iris haynei. I have a small amount of seed of this species, too.
Does seed of this species benefit from cold stratification? If so, why? It seems to me that there wouldn't be enough continuous cold in its habitat for seed to have any need for cold in order to germinate.
Title: Re: another oncocyclus question
Post by: Oron Peri on November 30, 2014, 10:57:23 AM
Bob,

Iris haynei doesn't need cold stratification.
In its habitat temperatures would never go below i would say 5c in sever winters.
Oron
Title: Re: another oncocyclus question
Post by: penstemon on November 30, 2014, 04:29:45 PM
Thanks. That's what I thought. I had a discussion with someone regarding the cold requirements of a non-iris, Vernonia larseniae, since stratification was recommended, but the vernonia grows in a habitat where sub-freezing temperatures are not that common, so that a requirement for cold would seem a poor strategy for survival.
I grew a hybrid of I. haynei, Galeet, I think, for many years in the garden here, so I also wonder about inherited cold hardiness in the lower-elevation species.  That is, which way the oncocyclus species dispersed; south to north, or vice versa.
The insistence on maintaining green leaves during cold winters (e.g. Iris iberica, paradoxa, sprengeri, etc.) seems very strange to me, too.
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