wisteria

I recently redid my betta tank & added some new live plants, one being some water wisteria. I tried this plant once in the past with a different tank (planted in substrate) but it all ended up dying from the roots up. This time, it looked like the bottoms were mostly rotting when I took it out...

all the plants that i have listed above i have in my 15 gallon freshwater tank.. with my 4 emerald cories.. and my 6 male guppies.. i've been haveing trouble keeping plants lately it seems all besides my anubis on lava rock is the only one that seems to be thriving. I've only have the others in...