Nothing provides a steady shot of color to your yard more than annual flowers. Once they begin to bloom they will keep producing flowers for the rest of the summer. Perennial flowers are beautiful but are usually only in bloom for a couple of weeks. For non-stop color and plenty of flowers for cutting, annual flowers are ideal.
After waiting for seedlings or young transplants to get established and begin to push out growth, the last thing gardeners are inclined to do is cut them back. But some judicious pinching right now will pay off with many more stems and flowers than if they had been left alone.
Pinching is a term to describe a very light pruning of the tender, new growth which is usually done with your thumb and finger.
On many plants, the topmost shoot is dominant and inhibits the side shoots. If you remove the tip of that top shoot, the side shoots will be released and able to grow. I experienced this first-hand one summer when I grew a variety of tall snapdragons. The plants shot straight up with a single large flower stem. The plants blew over after a storm and I assumed my flower supply was lost. But within the week, the side shoots all started to grow and I ended up with many more flower stems for cutting than I ever would have had.
I had a similar experience with sweet peas. These fragrant beauties need a trellis to climb up and if left unpruned I get a modest show. One year, the tips got nipped off and I figured the crop was lost, but instead, side shoots from the remaining couple of inches of stem all started growing and by mid-summer I had my best crop of sweet peas ever.
Other annuals that I find respond well to this terminal pinching include tall ageratum, tall zinnias, tall, marigolds cosmos, scabiosa, and also the herb, basil.
In general, it’s the taller varieties that are grown for cutting that need this treatment the most. Short, bushy varieties of zinnias and marigolds will need deadheading, where you remove their faded flowers, but these varieties will be bushy without your needing to pinch back shoots.
A variation on this pinching is also helpful to keep hanging baskets, planters and window boxes nice and full. Do not wait until they become thin and straggly in late July to do this, there just won’t be time for them to respond. By regularly pinching and lightly pruning these plants, they will stay full with lots of blooms and healthy leaves. Even the plants that are meant to spill over the sides, such as scaveola, bacopa, licorice plant, sweet potato vine and wave petunia will look their best with regular light pruning to encourage new growth.
Photo courtesy the Cornell Home Gardening Growing Guide online.