Perennial flowers are well worth the investment as they come back year after year and many are low maintenance, easy care plants. Many perennials will attract butterflies and hummingbirds. Some perennials will spread while growing, and most perennials can be divided in late winter or early spring so you can start off with a small garden and expand it over the years by dividing the plants. If you plant perennials in mid-summer, make sure to water them enough to keep the soil moist. Adding mulch around the plant will also help to retain some moisture and prevent weeds from growing.
Although many people are not aware of this, one of the best things you can do to keep your perennial garden looking well groomed all summer is to prune the plants regularly. One of the most important types of pruning we can do is to deadhead spent flowers. This will often extend the blooming period of the plant by encouraging new growth of additional flower buds. How far below the spent flower you prune depends upon the growth habit of the plant. Look on the stem below the spent flower and see if there are any new buds forming. If there are, prune to just above the first flower bud that is below the dead bloom. This works well for Rudbeckia, Black-eyed Susan, Shasta Daisy, Echinacea, Coneflower and Bee Balm.
When you see no more flower buds on a stem on these plants, cut the stem to the ground. This will promote lush new growth at the base of the plant. Although you will probably have no additional flowers for the season, you will have attractive foliage growth.
Many perennials like Coreopsis, or Tickseed have fine foliage and small flowers. Rather than removing individual flowers, these plants can be deadheaded by shearing off the tops after the first bloom. You can actually remove the foliage of these plants to within 4 to 6 inches of the ground if you want to. This shearing helps keep the plants in their place and promotes re-bloom.
Daylilies are another perennial that can begin to look straggly in mid-summer. They produce only one cluster of flowers on a stem. You should remove the entire stem once the flowers have finished. On repeat-blooming daylilies this will encourage re-bloom. On daylilies that bloom only once, removing spent flower stems simply improves the appearance of the plant. If the foliage of a daylily begins to look bad, you can cut it down to within 2 or three inches of the ground after bloom. This will promote lush new growth.
Some perennials just get too tall for their space, or so tall that they tend to fall over. You can reduce the size of these plants by cutting them back once or twice before they bloom. Although this will delay blooming slightly, you will generally have shorter plants and more flowers. This technique works well for Bee balm and Purple Coneflower.
As long as your plants are healthy and doing well, cutting back your perennials really boils down to what works best for your garden and your schedule – and doing it will just give you more chances to get out and enjoy your garden.