Expert: C.L. Fornari - 7/2/2010

Question
My petunias in hanging pots are getting very leggy and are not producing as many blooms as the ones I had last year.  I was told to cut them back.  How far back do I cut them and should I do all the stems at once or just a few at a time?  I do remove all dead blooms as soon as I see them.

Answer
Louise,
It depends on what kind of petunias you have.

If you have regular petunias, you'll want to clip off old flowers by snipping the stem below where the flowers are attached to the stems. This removes the developing seeds, which is the important part - just taking off the wilted flowers isn't enough. If you have Wave or Superpetunias, you don't need to deadhead.

Either type only form flowers at the end of the stems however, so if you don't want them to get leggy you need to start clipping these stems at the START of the season and continue every week.  Since they are all too long now, however, you can clip about 1/3 of them back now by cutting off 3/4 to 1/2 of the length, and cut another 1/3 off in ten days to two weeks and the final 1/3 back in another 10 to 14 days. At the same time, give them the fertilizer of your choice but only after watering the plant well.  There is a more lengthy explanation of this at my website: http://www.gardenlady.com/problems_with_petunias.html  

I hope this helps!
C.L.