I have a single Betta. I purchased a java fern as well as another type of plant and the second one polluted the tank because it wasn't meant to stay underwater. I read up on it and found that pet stores will sell these anyway.

Another thing. Beware of heaters you buy at the pet store. Try them out in a separate container BEFORE you stick them in the tank with your precious fish. I'm glad I did this because two of the ones I purchased went well over 100ú. I had to take them back. I use a digital thermometer to check the temps with.

Here are some links that might be useful.

Dying plants
www.fishchannel.com/freshwater-aquariums/planted-tank/dying-plants.aspx

All plant species (list)
www.fishchannel.com/fish-species/plant_all_landing.aspx

Plants [Archive] - Aquarium Forum
www.aquaticcommunity.com/aquariumforum/archive/index.php/f-65.html?s=5c0d5f37fd0921992dcbfd9bab04a6ec

Submerged and submersed. In nature aquarium plants grow mostly in submersed then submerged conditions. Bog conditions.