Gardening with Gary

Gardening Advice from an Expert

Petunias

Member MBabyCrush writes~ Thank you for your last answer. You seem to always know the answers. Now, I'd like to know how to care for petunias!

A. Petunias are the easiest annual to grow I would say, maybe right alongside of zinnia and marigold. I was 12 when I started with these beauties. You need tons of sun and heat for them to do well, though. Then, of course, lots of water, as they dry quickly in the intense summer sun. They do not tolerate drying out as the first two annuals do. They wilt, pout, yellow and reduce their flowering. So, keep an eye on them at all times, especially when you are lacking rain.

Feed them every two to three weeks with a good general garden fertilizer as Rapid Grow, Miracle-Gro, Peters, Scotts or Hyponex. Do not go too heavy with the first number, nitrogen, as you will get a lot of foliage and lack the blooms. The middle number will boost blooming.

Watch for insects, but they are pretty good about being resistant to them. You may see white flies or aphids. Treat immediately to prevent spreading. Keeping weeds down around them will decrease the chance of insects and provide more water and food for your plants.

Nancy writes~
My gardening book says to cut back my petunias at the end of July. Does this go for wave petunias as well that bloom without help anyway?

A. There are two reasons for this advice, so read and see if you wish to cut yours back. It is a general rule of thumb, but I have witnessed fine beds of petunias which were not cut back and into September looked good until the days shortened too much and the temperatures dropped, linked with seed production.

The plants tend to get lanky...that is the best word for it. The stems keep getting longer and the flowers appear in the side shoots, getting higher and higher. if you do a severe cut back of 1/2 the plant size, this will push out the bottom shoots and the plants will get bushy with the flowers closer to the ground and in general providing a neater look.

Secondly, the old flowers fade, but seeds are produced in the ovules. As the plant grows, more and more seed pods are formed. Being an annual, the petunia will slow down foliage and flower production and put its energy into seed production as that is its purpose dung the one year life span, to make new plants to take over after it dies. By cutting way back, many or all of the seed pods will be removed, thus making the plant start over by producing more flowers to get seed. In the fall, the plants can be allowed to go to seed and you may get seedlings the next spring if your climate is not severe. But, I prefer buying new six packs in the spring, or start my own from a seed packet of a good F1 hybrid.