I wouldn't worry about them, sometimes hostas can take a couple of years to take off. If you are wanting something faster or something to take more sun, just move them to pots for a while and plant something else. You may consider growing squash, it grows super fast, gets large leaves and of course you can eat it! It takes strong sun. With zone 8 and afternoon sun, you are probably not going to be able to grow hosta in that spot, and maybe not at all. Hosta have to have a defined winter period to perform and also besides just direct sunLIGHT, they don't like strong summer HEAT. so even if they are in the shade, the heat may do them in. There may be some varieties more suited to those conditions, but I'll let someone else chime in there. I'm not familiar with this.
