Are your annuals looking spindly? Out of control?
The best thing you can do is pinch them back. This encourages your annuals to create more shoots on the remaining part of the stem, which in turn gives you more flowers.
All you have to do is pinch or cut off the last inch or so of the stem. This does a couple of things. First, like I noted above, it causes the plants to create clusters of stems to replace the one you pinched back. The plant will end up being shorter and fuller. Secondly, it will produce more blooms. By pinching off the stems you are redirecting the plant’s energy from producing seeds to creating more flowers.
If your annual is out of control, then you may have to pinch a few of the stems back to the last or second to the last set of leaves. Although it will product great results I don’t suggest doing this to all the branches as it will end up looking like a hedge trimmer ran amuck through your flowers. A few critically placed pinches more often will reward you with a bushier plant.
I usually pinch back my annuals about once a month, but not every stem. That way the “trim” isn’t as obvious. Cut back the thinnest stems at that time. This will keep your plant blooming continually.