Plants that can withstand flooding?

Starting a food forest from scratch on 1/4 acre in Zone 9 (Houston). We've lived here for 18 months and have had 3 major floods in the yard.

Need help and suggestions to mitigate flooding (that will be HOA ok), and plants I can plant in the low spots that tolerate occasional flooding AND heat (100 degree+) weather for several weeks of the year.

Also for your reference - blackberry, blueberry, raspberry, tangelo, hydrangea, basil, rosemary, passionfruit, and avocado do not tolerate being underwater (thus, starting from scratch. Well, my 2 Flame Seedless grapes survived, though they aren't thriving.)

ANY thoughts, suggestions, or random commentary welcome

Notes:
I am on a corner with a stop sign, so the areas that flood the most often must be kept at 24" or below in height. My yard faces south (front yard) west (side yard) and north (back yard.) My eastern facing portion is heavily shaded. I have a lot of shade from non-food trees in the front that will remain (not cutting down the 40 year old oak!)

Hum... Kangkong (Ipomoea aquatica) and Taro (Colocasia esculenta)?

Elderberry, watercress and cattail will do well with wet feet. I think perhaps the downside is in lack of sufficient rain to keep the ground wet where they are planted. These may require regular irrigation, but should survive a flood if things such as moving debris in the floodwater doesn't uproot them.

Edible day-lily tolerates both very wet and very dry soil from time to time.  As for plants that do not tolerate being under water I wonder if planting them on a mound or huglkuture bed would help.

I will second daylilies as those are growing on my property in a very wet, seasonal flooding area.  

Willow plus you can weave it to make raised beds
David

When I lived in Houston, my back yard would flood from a nearby creek, but most of the year it was dry. A local author of native plant books suggested I try Beautyberry bushes to withstand both flood & drought. It can be tall, but can be used in the background or just prune it shorter. Here's a bit more info (but it did not state it was flood tolerant and I never tried it in my yard before I left Houston). Good Luck!  
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