RE: iris lifespan

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Sean

I. setosa growth profile has followed that pattern here in upstate NY, though I can not say if it is representative of all wild populations from its natural range of adaptation. I have grown only a small sampling of total setosa population genetics. However, Alaskan and Eastern Canadian sources of seed grown plants performed the same here. Much like this.

Good plant establishment in seedling year followed by bloom in second year. Third year bloom sometimes equal to second year bloom, not always. However, following either one or two years of bloom, plants begin a steady decline and eventually disappeared, despite all efforts to meet their cultural needs. I observed little if any vegetative increase here in NY. It appeared that seed propagation was necessary to maintain pure setosa clones over any length of time.

 Someone advised me years ago that you could reverse the decline of setosas by moving plants to a new location in the garden. However, I have not started any new setosas since, so have no way to confirm.

 Along similar lines I do have an inter-specific hybrid of setosa x siberian hybrid which has an odd growth pattern. It would be tempting to attribute its peculiar growth habit to setosa parentage. This hybrid plant grew like a bandit and flowered in its second year. It then went into an odd dormant like state for years with very slow, if any, vegetative increase. It failed to flower for several years though appearing to be healthy. It lived in this sedentary state until my patience gave out. I then transplanted it to a new location in the garden. The year following transplant it again flowered for the second time in a decade.

 These observations taken together suggest to me that setosa may not increase vegetatively in the wild. Perhaps it is a short lived perennial maintaining populations by successive generations of seed grown seedlings.

 Are there setosa growers who have different experience or can shed some light on this ?

 Of course, siberians are very hardy, long lived, and increase vegetatively. Just sharing observations.

 irisman646