They are easy to grow in a cool climate, like moisture and frost, flower for about 3 weeks in spring, multiply quickly and develop deep green, 80-90cm tall strap like foliage after the flowers. They are herbaceous, and, seem to need a year or so after being divided to get going again. They can grow into very large clumps which need 2 people to lift, (I'm speaking from experience here). They are trouble free, but can be disappointing in areas with mild winters.

Wattle blossom pretty much summed it up :-)
They make a good companions for roses, liking more water that bearded irises, and will tolerate some lime in the soil, but do well in acid soil.
Mostly in blues, but new hybrids are coming out all the time, and quite a few pinks, mauves. Lots of whites, and some yellows. Very interesting mixed tones in some of Barry Blyths newies, and lovely full rounded blooms.
They like some depth of rich soil, moist all year, but not wet like the various water irises. I can probably spare you a few divisions to try, if you remind me next year Dee.

There many different types of iris. Among the beardless ones the most commonly grown are Louisiana's, Japanese, Spurias, Siberian, I. pseudocorus, I. virginica and I.versicolor, and the lovely crested irises (I. tectorum, I. japonica, etc) and the winter irises I. unguicularis, I. lazicus. .....and many, many more ...... :-)