Not all annual flowers and plants require pruning/deadheading (removal of spent flowers). Many are self-cleaning and can be left alone. Others, such as the ever-popular geraniums, will need and benefit tremendously from deadheading. Deadheading annuals encourages healthier, bushier plants that produce more blooms.
How To Deadhead
Deadheading is a simple task which takes a few minutes. If you've never dead-headed before here's how go about it:
First, keep a watchful eye on your flowering plants, paying close attention to blooms that are past their best. Once a flower has started to fade remove it from the plant with a quick snip from your pruners. Alternatively, if stems are thin or soft, knip it off with your thumb and forefinger. When doing this, try to remove just the spent flower leaving the new buds beneath intact.
The Many Benefits of Deadheading
Your flower beds and containers now look neater due to the lack of fading blooms, but how else has this deadheading process helped? By removing the spent flowers we stimulate more foliage growth - and more growth means more blooms. We have also prevented some plants from setting seed which, if they did, would trigger the production of a hormone which causes flowering to shut down completely. Some annual plants, such as Coleus should not be allowed to flower, otherwise you can expect decline of the plant. So, by our slight tinkering with Mother Nature, we can often force annual plants to produce more flowers and bushier plants.
Cutting Back at Time of Planting
Many annual bedding plants are grown commercially in what we often purchase at the nursery in "cell-packs". Annuals in cell-packs, or smaller size containers, will often "stretch" as a result of growing in such a restricted envirnment with little soil. When planting annuals that have become stretched, or leggy, in the pots they were grown in, it's a good idea to cut them halfway back at planting time. Yes, your Impatiens will look like green stumps, and you will most likely be cutting off all the blooms, but, once planted, it won't take long for them to flush back out into fuller and bushier plants than they would've been with no cutting back.
Cutting Back During Summer
By mid-summer, if an annual bedding plant growing in a bed or conatiner has become leggy and unproductive, simply cut it back. The amount of foliage you remove will of course depend on the size of the plant. When you cut an annual plant back, make sure you don't cut back to a point in which there are no leaf buds left.
At any time during the warm season it is okay to cut back dead or ugly foliage.
Winterizing Your Annual Beds And Containers
The best way to winterize an annual flower bed or container garden is to plant Pansies in it!
Otherwise, if you don't intend to plant Pansies or some other cool season annuals, remove summer annuals that have finished their bloom cycle and/or are dead or dying from the beds or contaners they are growing in. Leaving these plants in beds or containers for the When winter has arrived, and your perennials have either died back or stopped growing, you can first remove all dead foliage and then apply an inch or two of compost or mulch around plants. Leaves work great for mulch as well.
When grown in containers, some annual plants can be overwintered indoors. Before bringing any outdoor plant inside your home, inspect all foliage, stems and soil for insects. If insects are present, pick them off, or wash them off with water from the garden hose.