Most of the people I've talked to said to stay away from this stuff but I've gotta say, it's pretty awesome! I've never seen anything that grows so well. The fish love it. I let it get tall enough that it curls a little at the top then I cut it. I've even replanted some of the cuts I've made and I'll have to trim those soon too. If you want to fill in some bare spots, get this stuff!!! It's a great filler.