Question
When I purchased these "Wave Petunias" in a hanging basket they were so beautiful and the talk of the neighborhood. After 6 weeks they have thinned out and look awful. They are still blooming. They get the afternoon sun, have been deheaded, fertilized and watered on a regular basis and they really looked great until the past week. Someone told me to cut them back because they are really long (24-30 inches) but I wanted an "expert" answer before I began whacking on them. We live in the deep south. (Alabama)
Thanks, Jo

Answer
Jo,
The waves grow long, and as you can see, form flowers at the end of the stems.  So the longer they grow, the more stems you see, especially in a hanging basket.  You don't have to deadhead Wave petunias, because they don't make seeds like the normal ones do.  But in order to keep them full and bushy, not leggy and stemmy, you need to cut the stems back.  If you'd just bought the basket I'd tell you to cut four or five of the stems in half every week.  But since your's is now very leggy do the following: right away cut 1/3 of the stems back by cutting off 1/2 to 2/3 of their length.  After you water them well, fertilize with a liquid fertilizer.  Next week cut another third the same way, but no fertilizer that time. (Always water them when dry, however)  The third week cut the final stems back, water first and then fertilize again.  Fertilize them with a mild mix of a liquid fertilizer every other week for the rest of the summer.  Once they have started to bloom again after your pruning, begin cutting three or four of the stems in half every week for the rest of the summer.

When you cut a stem back, it will branch out into two or more stems just below the cut.  Since these new stems will produce flowers at the end of their new growths, you will have shorter bare stems and more stems making flowers.

Another approach is to cut all the stems back by 2/3 at the same time, water and fertilize.  This works too, but you'll have a completely bare and stemmy plant for two or three weeks before it starts to bloom again.

By the way, the stems you cut off can easily be rooted by removing their lower leaves, coating the cut end with rooting hormone, and sticking the stems in a pot of new, clean moist potting soil.  Keep this pot in a bright but not sunny place until they are rooted, and then plant them in the ground or in baskets.

I hope this helps,
C.L.