Does anyone grow this? Your thoughts about it? I'm curious about why all the gardening sites seem to tell me that it's grown as an annual despite being a perennial. Is it some sort of a flop in year 2 or does it not survive the winter well or what? Is this a plant you could see growing in little nooks like between paving slabs, cracks in paving, chinks in walls, etc.? Or am I really heading for disappointment with this?