Expert: C.L. Fornari - 6/15/2011

Question
HI
We grew some wave petunias from last year's seeds and they have grown beautifully but aren't producing any flowers.  I also bought some plants from the nursery and our plants are bigger but they just aren't blooming like the nursery plants, that are growing in the same planter and have received all the same liquid fertilizer, sun and water.  Are we supposed to pinch the runners off to make them produce flowers?  We have never done this before but thought we would like to give it a try.
Thanks for your advice,  Kay

Answer
Kay,
Where did you get the Wave seeds? Hopefully you got them from a reliable seed company, not through ebay or from another home gardener. Why do I ask? Because if someone collected seeds from a Wave petunia, those seeds wouldn't produce the same plant. Wave is a hybrid and the seeds from hybrids don't usually grow into the same hybrid. If you got the seeds from another gardener, or from a source that isn't a real seed company, that could be the problem.

Secondly, the plants from the nursery were most likely raised in a greenhouse where the light and fertilizer were optimal. Some growers also use growth regulators that make the plants shorter and tighter but don't suppress flowering. That may be the case here - professional growers use regulating chemicals so that the plants don't sprawl and become leggy...not only does the customer want to see a full, tight plant with flowers on it, but if the pots are in a tray close together, leggy plants would be all over each other and hard to separate once the pots arrive at the garden centers.  Also, most customers want to see at least a flower or two on a plant before they buy it, so growth regulators keep the plant smaller but it still comes into bloom so it's more salable at the garden center.

Long story short?  I'd pinch the stems of your plants not merely to stimulate flowering but to promote bushiness. As you probably have seen, petunias produce flowers at the end of their stems. But if yours already have long stems you don't want to have a huge area that is just stems and green before the flowers start.

Use a "shotgun" approach, pinching some of the stems back so they are only two or three inches long, pinch others in half, and pinch the last third back by only an inch or so.  You'll end up with a fuller plant this way. After that, wait for about two or three weeks. You don't say where you live, so I have no idea if it's really sunny and hot there or cool and rainy...and I don't know how long you've had these in your planter. So it's hard to guess if other factors such as cool or cloudy weather are coming into play.

If you've gotten true Wave seeds, however, and given enough sun, and your pinching, they should respond soon with new growth and flowers.

I hope this helps,
C.L.
www.gardenlady.com