Sorry, never grown them but here is a link that might be useful: wild white petunia (Petunia axillaris) at Annie's Annuals & Perennials

I didn't have much luck WSing the wave petunia seeds I'd saved, but they came back in the pots that they were planted in last year (we had a mild winter). I did receive a packet marked "Petunia Cascade: White/Purple/Pink" in trade and these WS'd REALLY WELL. Are fluffy and full along the front of one bed. Don't seem to "self clean" as well as Waves do, but I am out there deadheading almost every day anyway so I just give them a once over and they seem to love it. I am going to look for more of this seed for next year.

It's not uncommon for petunias to look a little worn out after a rain. Just deadhead the blooms that have gotten beaten down and you'll probably have new blooms in a few days. Just as lisa455 said, petunias are more of a cool season plant in Louisiana, but they should make it until June before you need to replace them (North Louisiana). When they start getting really leggy, pinch them back about 1/3. They'll rebound really quickly.

Betty, Most petunias really are cool-season flowers and, no matter how great they look in March-May, most start to struggle when the June heat arrives, especially if they are in full sun. Mine do better in part shade. So, I plant a few in early to mid-Spring but am prepared to rip them out and replace them if they start looking too ratty once the heat arrives. Some years, though, they do surprisingly well and make it through the whole summer, or at least most of the summer. The petunias I have found to be the most heat-tolerant are the Laura Bush petunia (you can see photos and find seed for Laura Bush Pink and Laura Bush Purple at wildseedfarms.com. They are the only petunia I've ever grown that laugh at the heat, and if properly watered and cut back as the package directs, get better and better as the weather gets hotter. Most of the Wave petunia lines also perform well in heat, but I've been less than impressed with the white Wave petunias. However, Tidal Wave Silver is very heat toleranant and the Dallas Arboretum, which conducts very extensive plant trials every single year, named it the best white-flowered petunia for heat after their 2005 trials. I've linked the arborteum's trial report for you. It is long, but you page through it very quickly like a slide show, and it is full of info on which plants proved to be tolerant of a climate like ours and which didn't. For folks who aren't familiar with the Dallas Arboretum's Jimmy Turner, he is amazing and is doing incredible work there. In this slide show report, Tidal Wave Silver is on page/slide 67. Tidal Wave Silver isn't pure white though. It is more-or-less white, with whitish petals, a dark purple center and some purple veining. When you grow them from seed, some are a little more pale purplish than white, but they all are gorgeous. I am sure that in many cooler parts of the country, petunias are a great summer flower. Here, though, the heat tends to eat their lunch. They also like well-drained soil and hate being too wet, so this year has been hard on them in the rainier parts of Oklahoma. And don't forget Mexican Petunias (although they are not actually true petunias--they are ruellias). The native ones that grow on the edge of our woodland get no irrigation and still handle the heat well. Dawn Here is a link that might be useful: 2005 Dallas Arboretum Plant Trials