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Irises changing colour

14 Jun 2010
Cloudy 16°C / 61°F

9:54pm So the yellow iris buds have opened and they are not so much yellow as a light orange with a bright orange beard, actually very pretty and I would be very pleased if it were not part of an established clump. I googled to see if there was any explanation for this change of colour in two clumps of dark mahogany irises but not in the third clump at the other end of the bed. First of all there were several blogs saying categorically, No but definitely no, irises do not change colour… well maybe if they got hit by Round-up. However there were plenty of examples of irises changing colour without the assistance of Round-up. Eventually there were a couple of acknowledgements that Bearded Irises do change colour (along with Glads and Tulips).

One reason can be stress which causes production of certain pigments in the flower tissue to be suppressed so that what you see is the underlying colour without the ‘good’ colour that produces a particular shade. Once the stress factor goes away the irises can produce normal flowers again. Stress factors can include an overgrown and starving clump, heat and cold can produce short term effects. Self-sown seedlings are likely to come up a different colour. Then there are true genetic mutations or ‘sports’.

Some of what I suspect is going on is that unstable hybrids are reverting to their strongest genetic parent. I think that is what happened with Best Bet losing its blue colouring to become a more standard purple and at the same time the falls and standards became a bit smaller and lost their frillyness. Comparing photos 2 and 3, I think the same thing is happening here, the colour in 2 is a bit less rich, the flowers are a bit smaller and the falls and standards are much smoother. So is the yellow one a reversion to a parent or a sport?
The last photo is Allium Atropurpureum


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Really interesting. I hope it’s stress and that it will revert to its ‘proper’ colours. It’s a pretty combination right now, though!

Posted on 15 Jun 10 (about 9 years ago)

I don’t think they would change if they were multiplying from the roots – those should be genetically the same — only if they were coming up from seeds. I think envirtonmental stress, or possibly a change in the nutrients they are getting, is the best explanation. Most places in the country have had some very weird unseasonal weather this year.

Posted on 15 Jun 10 (about 9 years ago)

All of these irises are coming up from the same group of rhizomes, I always dead-head so there is no chance of seedlings. The changes in several groups of irises have been going on for two seasons, although this is the first year that it has become so obvious. It could be stress after a very early spring as rhizomes are near or on the surface but I am not convinced. I think that from the change in the flower structure as well as the colour, these are reverting to parental type. Hybridization may not be as stable as we are lead to believe. We’ll see what happens next year.

Posted on 15 Jun 10 (about 9 years ago)
kelly

kelly

Folia Helper

Canada4a

Isn’t that fascinating? But I LOVE the orange though, probably my favourite iris I’ve ever seen actually!

Posted on 15 Jun 10 (about 9 years ago)

Interesting. I don’t think I’ve ever seen an orange iris, so I like it too!

Posted on 15 Jun 10 (about 9 years ago)

Just gorgeous!

Posted on 15 Jun 10 (about 9 years ago)

I have an orange iris (a bit more orange than this) Iris Orange Slices in another part of the garden, it hasn’t flowered this year yet, maybe it is not getting enough sun.

Posted on 16 Jun 10 (about 9 years ago)

This will be interesting to follow. I have not had this happen…yet!

Posted on 16 Jun 10 (about 9 years ago)
TolCath

TolCath

Folia Helper

United States

This is interesting. I know some daylilies definitely vary easily in color, just from temperature: Sweet Obsession has a cool-weather pink and a hot-weather peach/apricot. And I have a variegated heliopsis that included instructions (as many variegated plants do) to remove any non-variegated foliage to prevent your plant from becoming entirely non-variegated over time.

If my reblooming irises actually rebloomed, I would find it interesting to compare those flowers. I wonder — is it really in the flower or is it in the rhizome? is your yellow/orange iris coming from a piece of rhizome that doesn’t have the right color flower growing from it? If you divided the clump, would that piece produce only yellow flowers in future?

Posted on 16 Jun 10 (about 9 years ago)

There are two groups of rhizomes, with originally roughly the same colour irises though they came from different sources. Now both sets of rhizomes have yellow/orange irises from newer rhizomes.

Posted on 16 Jun 10 (about 9 years ago)

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