Neal, we grow our Louisianas in raised beds that are lined with rubber pond liner. I went to lined beds because the trees in our backyard were sucking out all the water.
The lined bed keeps them moist all of the time. I give the beds a sprinkling for about a minute twice a week. The lined beds save me a lot of water. The pond liner is expensive and I never thought it would pay for itself. But with the drought and all the increases in the water rates it may pay for itself yet.
I have grown a Louisiana iris in with the tall bearded iris in the past and it did well. Trees weren't a problem in that bed.
