Nobody has answered and I can't help from experience as I don't grow Petunias. But 'Wave' are just a branded cultivar of 'regular' Petunias so I assume anything that works for Waves will work for the ordinary ones.

Check out the various discussions of petunia cuttings. You could also see what folks do by asking on the annuals forum which I think may be more active.

How do you treat the mother plants to keep them alive this long? I have not had luck overwintering them in conditions that work for other non-hardy perennials such as Pelargoniums, Evovulus, and Coleus.

lol NHBabs - this is an errant seed which sprouted in with my Meyer Lemon bush. This pot has been coddled in the sunniest window in the house. I like the colour and the slight 'frilly' nature of the trumpet. I will try the other forums. Thanks guys. :)

Nancy.