As the summer progressed, most perennial gardens benefit from regular maintenance. With a little care you can keep your garden looking its best all season long. Some chores are necessary mostly for the sake of tidiness. Others help preserve health and enable your plants to perform to their optimum. One of the most important tasks is the practice of pruning perennials during the growing season. This month I would like to discuss two grooming techniques that are often neglected (or unknown) by gardeners: deadheading and cutting back.

Deadheading

One of the most important types of pruning is referred to as deadheading. This is the removal of old or spent dead flowers on your plants. Deadheading serves several purposes in our gardens.

First, dead flowers are not very pretty. Removing them improves the appearance of the garden.

Second, many perennials stop blooming after they form seed. Removing the fading flowers before they can complete the process encourages the plant to continue blooming. Thus deadheading can prolong the bloom period or can initiate a second flush.

Third, plants that self-seed prolifically in the garden can become a maintenance headache to control. Deadheading will prevent self-seeding.

To deadhead, simply cut the dead flowers off - using scissors or snips for lightweight stems or pruning shears for heavy and thick ones. Where to cut depends on the species. Sometimes you will need to remove individual dead flowers one at a time, or remove whole clusters of dead flowers, or cut off the entire flowering stalk or scape. A good rule of thumb to use when deadheading is to cut the stem at the first leaf or flower bud below the spent flower. For plants that have flower spikes that begin to bloom at the base and progress upwards, spikes should be removed when about 70% of the spike is finished flowering. Otherwise the plant will produce rather long and gangly looking flower spikes, full of seed capsules with only a few flowers at the tips.

Cutting Back

Cutting back refers to pruning a plant to renew its appearance or encourage a new flush of growth. It differs from deadheading in the amount of plant material you remove. With deadheading you remove a dead flower and its stem and perhaps a few leaves. Cutting back generally means removing foliage, even a significant amount, as well as possibly removing flower buds or deadheads.

For some gardeners cutting back substantial parts of an actively growing plant is difficult, even traumatic. Often people gasp in horror as they watch me "whack back" a plant. But trust me, for many perennials this procedure has many benefits. 

The subsequent fresh new growth can be every bit as nice as the early spring growth. Many perennials will produce a second (or even a third) flush of blooms. This technique may rejuvenate certain perennials, especially some of the shorter lived perennials, thus extending their life.

Cutting back or shearing can also be helpful for keeping plants within their assigned space in the garden. Often just removing tired looking foliage, plants with lanky growth or cutting back plants which have died out in the center is a blessing to a garden, improving the appearance of an entire planting.

Plants that are being cut back for purposes of maintenance or aesthetics should be pruned after flowering. Generally when plants are cut back after flowering the re-growth remains lower than the normal mature height of the plant. If rebloom occurs the flowers often will be smaller in numbers and sometimes in size.

In many cases, it is best to cut down to the start of new growth developing at the base of the plant, or to the basal foliage. Often, however, there is no basal foliage and the plant is cut all the way to the ground. In this case do not cut flush to the soil. Leave about 2 inches of stem, so as not to damage any new buds present slightly above the ground.

If you find such severe pruning difficult, you may want to go slow and cut the plant back in stages. Cut half the plant down to the ground, wait for new growth and then cut the remaining part of the plant. This procedure will not only be less traumatic for some timid gardeners, but will not leave as large a hole in the garden since the entire plant is not being pruned at one time.

After most perennials are cut back, it is a good idea to coddle them a little bit to promote new growth. Keep them well watered. Sometimes a light top-dressing with compost or liquid fertilizer gives a needed boost.

I discovered the benefits of cutting back by experimentation. I was unhappy with appearance of several spring blooming perennials in my garden in the early summer and decided to just cut them back to improve the overall appearance of my garden. The resulting fresh new growth and realm gave me the added confidence to repeat this procedure on other plants. Not all perennials respond with the same enthusiasm and results vary a little from season to season. But by experimenting and observing how the plants respond, I have begun to know and understand the growth habits of each better.

I encourage you to practice deadheading and cutting back. Observe how your plants respond. You will be amazed at the difference it makes, and will in many cases improve the performance of the perennials in your gardens.