Waves are not intended to be cut back or "pinched" since they are supposed to trail so none is needed. They also do not need to deadheaded.

But since all the waves are hybrids what you will get from your saved seed will not be wave-types. They will have reverted to parent stock and need some pinching. Try it on a few and see how they do and leave a few untouched to see which you prefer.

Pinch the stem off just above a point where 2 leaves sprout from the stem - a leaf node - approx. 4-5" along the stem. Two new branches will develop from that node.

Dave

Thanks Dave! I will try that with a few of them. So far, they look really healthy, so I am excited to see how they do this summer :)
Tara

I grew wave Petunias from purchased seed last year. I pinched them back regularly while they were still in plastic cups. partly because they were getting big, partly because I wanted to plant the cuttings. I popped the pinched off bits in pearlite, and almost everyone of them rooted. I ended up with lots of petunias! I am doing the same this year.