yes but it might get crowded if you put them all in... a 15 watt incandescent is equivalent to a 1.5 watt flourescent i think so its only .6 wpg if im correct and incandescents tend to heat the water... it might be a good idea just to go with 1 plant and see how it works
I am growing a plant right now in a 2.5 gal and having no problems. Using a 10watt florescent screw in bulb.
One plant seems to be ok. Especially if it is a tall flowing plant like anacharus or hornbeam.
Since they aren't low and spread they dont seem to take up too much room.
Both are pretty easy to take care of and root freely at the bottom.
I just keep mine in a clump, bound by a rubberband, and stick them under the gravel. Fish can nibble on them and swim in and out of them because they aren't too rigid. And if they start getting out of control you can just snip what you need off, and the other good thing about them is that they are so easy, it seems as you can put the excess into another tank and start another plant or three, because they seem to grow pretty easily.