Regelia and Regeliocyclus irises
Peter Taggart (Sat, 26 Nov 2011 16:48:40 PST)

The different species and their respective hybreds produce more or less
winter foliage if the weather is mild. They will continue to grow through a
mild winter. Plants derived from colder areas are less inclined to winter
foliage. The desert plants are more susceptible to bacterial rot than other
rhizomatous Iris, especially in warm damp conditions.
I try to dry the more southern species out to make them pretty dormant in
Summer, but I like to be sure that they have got their roots deep down in
order to sustain them better against the drought. The rest I keep enough
moisture on to maintain a leaf or two - it makes it easier to break
dormancy.
Once these Iris start to root in Autumn they will continue their growth
cycle unless slowed down by either cold or drought. I dry them out a bit in
mid winter for about ten weeks, they are then less likely to rot if cold
suspends their growth. The leaves are then fairly irrelevant, if they burn
in frost more will grow, just as with other bearded Iris

The roots can go very deep -I would guess three feet or more and are
designed to be efficiant enough to sustain the plants in desert conditions
Peter (UK)

On Sun, Nov 27, 2011 at 12:21 AM, Jane McGary <janemcgary@earthlink.net>wrote:

I'm looking for information on the annual cycle of irises in the
Regelia section and their hybrids with Oncocyclus irises, known
sometimes as "Regeliocyclus." When I grew these in frames in large
clay pots, kept dry in summer, they did not make significant leaf
growth until late winter. Now I have them in a raised bed inside an
unheated bulb house, and some of them never really went dormant last
summer, even though not watered, and their leaves are almost full
size now. I don't like to see this, because I can't grow Onco irises,
which make early foliage growth that then succumbs to disease during
our humid winters. Did planting the rhizomes out allow them to reach
down so deep that they had some moisture throughout summer? (The bed
has a commercial woven groundcloth liner over native clay.) Is this
bad for them?