Yes, really! Try Lowe's and Home Depot, too. Most have some clematises in those deceptive green plastic bags. Sometimes you can lift them towards the light to see if they're already growing but I've had great luck with them. I plant them in the cheap Walmart self-watering pots and they do very well.
I also grow my Japanese irises in the self-watering pots for the first few months, then plant them in the garden around August - September. They do exceptionally well and double in size. I just cut through the root ball with a knife.
