Since I first posted this, I found an alternative to Low Light plants for my Wild Betta's. I use Water Sprite.
Water Sprite does not require much care, likes medium light and when grown as a floating plant the roots hang all the way down towards the bottom of the tank offering hiding places for the Betta's. it also reduces the amount of light reaching the bottom of the tank which is good for many fish like Betta's that don't like strong light. Since I started using Water Sprite I have found that the fish love to hang out inside the dense root ball, resting between the roots a few inches below the surface of the water. The only problem with Water Sprite is that it grows so fast it can easily take over the entire tank so it has to be pruned once a month to keep it manageable.