Iris unguicularis

Mary Sue Ittner
Sat, 23 Nov 2002 08:07:39 PST
Dear All,

Seeing all those nice Iris pictures on the Australian Image list prompts me to announce that Iris unguicularis is blooming for me right now so we have Iris blooming in two hemispheres. In the past Will Ashburner and Cathy Craig both recommended cutting the foliage to the ground since the flowers are very short and could be obscured otherwise. I remembered to do this finally this year and have been charmed by these gorgeous huge flowers.

I looked it up again in my files to see if I could remember the exact prescription and found a very helpful response from Dirk Wallace. He wrote
"Winter Iris is a well loved garden plant in this neck of the woods and it seems to tolerate most soil types. Acidic soil is definitely not their preference but I'm sure they would still grow and flower OK if it wasn't too acidic and they received a dry Summer rest. Our soil is neutral to slightly alkaline so they thrive in ordinary garden soil. The original clump was growing in straight clay and wasn't doing too badly, but as compost and sand have been added (as mulch) they've picked up, and are growing and flowering better than ever. I feed them with Blood and Bone and wood ash in Autumn and a handful of Dynamic Lifter(pelletised manure-usually quite alkaline) in Spring. Not much else is needed except good drainage and a dry & hot spell in Summer to initiate flowers. The climate here makes them a very easy plant to grow. Our Summers are hot and dry(40+degC) and Winters are fairly mild(-4degC, day temp. above 10). Transplanting usually happens in Spring, after flowering, but if you get them at the right time in Autumn they'll still flower successfully. They need to be planted firmly and not dried off until they have an established root system. They always do better in clumps than singularly, for me."

I just wanted to report that in northern California where all our soil gets acidic quickly being leached by all our rain and where I have totally neglected this plant never having fertilized it and where we have maybe 3-4 hot spells a year that last for a day or two when you could sit outside at night without a sweater I am still getting this plant to bloom. So Dirk is correct, it is very adaptable and perhaps it is the dry summer that helps.

How hardy is it? Who else grows it?

Mary Sue

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