Start calling nurseries.

They don't grow well here, so there is no incentive for nurseries to carry them.

Hey Mike,

I garden in both San Diego Ca and Phoenix. In San Diego, the hostas do OK in the shade, but the snails and slugs are a HUGE problem- leaves all eaten up. I've never tried them in the desert- You'd probably need to take them inside during the summer, but not sure. I buy lots of plants online. One of my favorites is Forest Farm in Oregon.(mail order.) Good luck. Rich