Re: aggressive native irises

---

On 19-Sep-12, at 8:33 AM, Sean A. Zera wrote:

> They only spread aggressively under unnatural circumstances. It's
> basically
> gardening by livestock!
>

Iris douglasiana does this too. The clumps I saw in natural areas
were good-sized and healthy but the ones in cow pastures near the
Oregon/California border were enormous. The cows were not only
diminishing the grassy competition, but were also fertilizing the iris.

One year I was preparing a talk on Pacific Coast iris, so drove down
to California to photograph the species. I expected to astonish my
audience with photographs of the giant clumps of douglasiana, but
didn't manage to do so as the farmers had taken action. The pastures
were iris-free.

I should take a look next time I'm driving by - maybe they've regrown
from dropped seeds.

Diane Whitehead
Victoria, British Columbia, Canada