It's getting too warm for them. They don't do well in the heat. Think spring flower in Florida.

There is a fungus that kills Petunias. I can't put them in the ground here or the die within a few weeks, no matter what the weather's like. I had one that had come back for a 3rd spring, but it was also killed when I unpotted a struggling plant and put it in the ground nearby before I learned about this. Good description of what happens, BTW!

This year I got Angelonia instead...

How weird. I was just looking up information about petunias in Florida, what seasons they're good for and such and then I come back to GW and find a topic on them.

My experience with petunias is limited, but I had some in a terracotta pot last spring/summer that seemed to do okay. By July they were definitely showing signs of heat stress, but regular feedings of MG's All-Purpose Water-Soluble fertilizer kept them alive. At the time I was still very new to this whole gardening thing and so 'regular' for me was like every other day they were getting a dose. This constant feeding is probably what kept them from dying off and is probably why I did not see what you're describing.

At the current time, I have about 6 petunias planted around the base of my Knock-Out Rose and they seem to be doing okay so far. They get a fair bit more sun than what you describe though. They get near constant sun from sunrise until 4 pm with a very short break around 10:30 as they fall into the shadow of a nearby bush for about 20-30 minutes,then they're back in the baking sun. My biggest problem with these things is the near-constant need to dead-head them. I like working in my yard, but I don't like having to constantly fawn over one particular plant to keep it going (which is why I'm also not all that keen on having roses [the Knock-Outs were a gift]). These don't get fed nearly as much as the potted ones from last year, just a dose of Fish Fertilizer every two weeks or so, which is more for the roses than the petunias, but the petunias get the benefit. Aside from that there's not much special about where they're planted. It's native soil (sand) mixed with a bag of Black Kow and topped off with Pine Fines as mulch.

All that said, I will not be actively looking to purchase petunias again for myself. The ones I have now were actually given to me by my mother who had purchased too many for her planters. However, I do intend to purchase and sprout seeds since my mom is a pretty big fan of them. Hence my internet search, I was trying to figure out when to sow seeds to have them ready for her next planter arrangement.

And here they are:

Weird! Petunias were on the list of the plants that do well in the summer here. 8b Florida according to the University of Florida.

I have a book that covers Gardening and Landscaping in Central Florida (that's the name of it actually) and it lists Petunias as being cool season annuals for this area. I would almost chalk that up to being a typo in the book, but it actually says the same thing in a two or three different spots. Mexican Petunias (no thanks), warm season. Petunia hybrids, cool season. That said... I think I read somewhere that there is a native species of Petunia (or maybe it was Periwinkle) (Edit: I couldn't leave well enough alone and ended up looking this up. The native petunia is Wild Petunia, Ruellia carolinienses). If my memory is correct, then this one might be more tolerant of the higher temps. I suspect it is much like any other hybrid types, there are some that are more tolerant of certain temperatures than others.

This post was edited by Leekle2ManE on Thu, May 16, 13 at 21:55

You might want to consider Laura Bush petunias. In 2005 I read that they were "bred for Texas heat and humidity". This sounded like something I needed in central Florida too, so I ordered seeds from Wildflower Farms. The LBP have been blooming and reseeding for me since.

I've learned to yank the plants from the previous year even though they are large and lush In the spring, Removing them allows newer reseeded plants to take their place and prosper. Thus fresh, vigorous plants are ready when the summer heat hits. The year I didn't do this, the "old" plants began to wane as summer arrived and I found myself trying to help new plants establish in 95 degree heat.

At the time I bought mine, only a magenta color was available. Now there is a pink and a "mix" also available.

I have several spots of them throughout the garden. My favorite clump is just outside the lanai because a breeze will send their fragrance wafting through the house.

Here is a link that might be useful: Wildflower Farms

Those sound great, June! I love scented petunias!