In my 60g planted, I started out in October and the amazon swords I had in the left corner were about 4" tall. now, in about the beginning of January I saw them breaking the surface at about 24" tall, just to give an idea of how fast they grow. The link to my thread is in my signature if you want to check it out, I can also link some pics...but in a good environment for them, happy swords will easily reach above 20" in 2 months time. at least thats IME!
I will have the pics in order from when I first started it, (middle pic - the swords are so small they are almost invisible lol), about 1-2 months into it(bottom pic), and then currently(top one).
Also, I agree with Rivercats, I bought some crypts from petsmart and they grow fine in my tank, but I also got some grass plant which is non aquatic, so it didnt do very well
I also got some DHG from them, but I only buy the packaged plants, not the ones that come from their tanks, because frankly, my petsmart is not the best on algae control...