Re: Iris hexagona
>On Thu, 4 Sep 1997, Chris Morris wrote:
>> Dear All,
>> Living in the frozen North of the UK on the Northern side of Hadrian's
>> Wall I'm a bit worried about the small seedling I. Hexagona that I've
>> just planted out on my raised bed. A recent book suggests that it may not
>> flourish here (rarely get down to -10oC in the winter or above 25oC in
>> the summer).
Is this a Louisiana hybrid or a seedling raised from the species I.
hexagona? Than can make a lot of difference!
>Chris, I don't know which zone you live in but some of the LA's are
>hardy in zone 4. TWOI says I hexagona are hybrids from I fulva,
>brevicaulis, gigantocelulea (hope I've spelt that right?) and
It's I. gigantocaerulea (giant sky-blue iris in Latin!). Iris hexagona is
not a hybrid, but a species in its own right, distributed along the Gulf
Coast from Florida up into South Carolina along the Atlantic Coast. It
probably does not occur naturally north of Zone 8. You were confused by
the designation of the Section Hexagona for Louisiana irises. Named hybrid
varieties of Louisianas do contain genes from the species you listed, but
Iris hexagona itself has been little used if at all in Louisiana
hybridizing, since it is not found in Louisiana where all the activity
Where I have seen I. hexagona in the wild in Florida, it has been growing
in sandy soil but along the margins of drainage ditches where plenty of
water was available all year long.
Fulva is hardy in zone 4. Nelsoni not and probably not
>brevicaulis either. So whether your seedling is hardy depends on
>which species it has in its parentage. But put it in a protected
>spot and put a brick or stone on it to stop it from heaving. Let us
>know please how it does. LA's need a lot of water but I don't know
>how much during the winter. Has anyone else an opinion on this?
I. nelsonii and brevicaulis are definitely hardy at least up to Zone 5 and
possibly well beyond. I suspect that in Chris's area the ground rarely
freezes and so the brick would not be neccessary. It would just provide a
place for slugs to hide and feast on the iris rhizome.
Having visited northern England a number of times at different seasons of
the year, my impression is that while I. hexagona and other Louisianas
would probably survive the winter there without trouble (it's about equal
to our zone 6 or zone 7), they probably would not care much for the long,
cool summers. Louisianas have not been very successful in England, or so
the BIS Yearbook for a few year back opined.
Department of Biology
Hampden-Sydney VA 23943