plant them at their recommended depth. I had the same thing with my cannas and having their stem underground didn't bother them at all. I looked at some sites that had pictures of the sowing directions for glads and it doesn't appear that that presents a problem for them. 6 of my 8 glads are already above ground. It stated in the article that I read that 60 to 120 days after the leaves mature they bloom depending on the variety of glad that you have.