I have cryts and anubias in my 20 gallon because I only have 28 watts (T-5) lighting. I also have microsword in there and remarkably, it has not died yet but it's not doing much, either. I also have had no ferts other than plant spikes so whether the microswords last or not, I haven't a clue. They remain nice and green.

My light comes tomorrow for my 55 gallon. That's 130 watt (T-5) but still not up to 3 watts per gallon. I will see how it goes and just have to add more if needed, I guess.