Iris color

Rodger Whitlock
Sat, 02 Feb 2013 21:45:33 PST
On 2 Feb 2013, at 13:03, Karl Church wrote:

> Hi folks, I'm new to PBS & recently started attending Master Gardener
> classes. Last meeting a classmate stated that all of her Irises had changed
> from multi-colored to all yellow. She had pictures of her yard showing many
> different colors & then again with them all changed to yellow & she wanted to
> know if anyone knew the cause for the change. Anybody out there have an
> answer for her?

What kind of irises? Bearded? Spurias? Pacific Coast? Reticulata? Oncocyclus? 
Reglia? Limniris?

At a guess, she is referring to "Dutch irises", bulbous ones that are very 
complex hybrids, which you can buy as mixed colors. I've even bought them at 
Safeway in boxes (in the fond hope, not realized, that they'd be Spanish 
irises). Mine, originally a mix of blue, white, and yellow, are now all blue.

This happens because different cultivars respond differently to local 
conditions: some thrive, some die out. QED.

So her irises haven't changed. It's just that only the yellow ones have 
survived, but they've increased. In my case, I suspect it's that they were 
planted where they are waterlogged in the winter, a situation that puts many 
bulbous plants to the test.

The same thing happens with some other plants, too. One color is, for reasons 
unknown, hardier than the others and survives where others die out. I think 
there's a yellow dahlia that's notably hardier than most and takes over dahlia 
plantings left to their own devices over winter.

Rodger Whitlock
Victoria, British Columbia, Canada
Z. 7-8, cool Mediterranean climate

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