Texas... an amazing amount of rain you folks have been getting. Glad the dahlias are your main concern, instead of house flooding.

I see that you are using last season's 'mother tuber,' and that the new tubers have been either stripped off or rotted. You might see a last-ditch effort of sprouts off the green stem, but I doubt that tuber will give you any more new sprouts (don't take off the old tuber at this stage... it might still have some nutrients to feed up into the stem). Let it dry a touch, then replant all the way down so only an inch of stalk sticks out of the ground. I would trim the top hollow cane flush with the stem division, to keep water from sitting and rotting, as well as the other places I marked on the attached image.

Thank you so much! My family was very blessed. I live in Houston and my area was not flooded.

I have the tuber sitting in perlite but I'll take it out and follow your advice.