Garden Life: Prune your plants with purpose

By Robb Rosser, Columbian Gardening columnist

Published:

 
photoRobb Rosser

The key to understanding how to prune is to answer the question, “What is the purpose for pruning this particular plant?” The most effective reasons for pruning are to help establish the shape of a plant along its natural lines; to improve flower or fruit production; to control the time of bloom, as in pinching back chrysanthemums, and for espalier and hedge shaping. These are all methods of seasonal pruning that enhance a plant’s best qualities.

The general purpose of pruning is not to reduce the size of a plant that has grown too large. Pruning stimulates growth. Weak growth can be stimulated to grow vigorously by hard cutting back, and light pruning best checks vigorous growth. This is important to know if you’re fighting to keep a large shrub within the boundaries of a small space. The best pruning advice for a plant that is too large is to move it.

Plants that can be pruned from late winter into spring are plants that will bloom later this summer on wood produced in this growing season. Some examples include abelia, Rose of Sharon (hibiscus syriacus), butterfly bush (buddleia davidii), caryopteris, hypericum, shrub roses, and Russian sage (perovskia spp). Hard pruning will produce a well-shaped shrub that flowers vigorously in late summer or fall.

Prune shrubs grown for colored winter stems shortly before new spring growth begins. These include the shrubby dogwoods (cornus alba and cornus stolonifera), the bright salmon-red salix ‘britzensis’ and the ghostly white-stemmed bramble rubus cockburnianus. The key to successful pruning of all of these shrubs is to keep them eternally young. Vigorous new shoots grow quickly, are more brightly colored and bloom more freely than older, unpruned growth.

Spring blooming plants flower on buds that formed last year. Prune these only after they have finished flowering in late spring. A prime example in Washington State is the rhododendron. Only after the plant has finished blooming would you deadhead, or snap off, the spent flower heads. This is pruning to encourage next year’s bloom. You can also reach into the shrub and cut out crossing or overly long branches to enhance the natural shape of the plant. Other spring bloomers include azaleas, forsythia, mock orange and flowering quince.

A garden is a part of nature and nature is a great metaphor for life. We work with Mother Nature; we don’t take over her job. Ideas come to us and we take the time to muse and ponder. By thought and effort, we change what we think needs to be changed, now or next year. Few creative projects stay with us for as long and last through our personal transformations like a real garden does.

Many homeowners focus on mowing, trimming, edging, weeding and spraying. Those who consider themselves gardeners spend as much time puttering, planning, dreaming and, yes, just enjoying the garden. To experience the pleasure of gardening, you need to expect more than mere results. It is the accumulation of moments, a sustained sense of joy that stays with us longer than a newly mown lawn or the blooms of one flowering shrub.

What a wonder it is to see a simple stand of daffodils emerging from a bright patch of lawn. How clever we were to plant the cherry-red geranium at the foot of a dusty yellow rose. It’s possible that your five-year-old patch of delphiniums, tall and stately, bluer than your memory of the sky in late spring, will die one winter after every effort to give them the best conditions.

You might be sad for a while, and then move on. We don’t forget the ethereal beauty of what we once had in a garden. There are too many good memories on which to linger. In turn, we might learn to find unexpected solace in the rough, more reliable nature of the common daisy. Sometimes simple is best.

Work in the garden. Dig a hole with a shovel. Put a plant into the earth and shape the soil around the base of the plant with your bare hands. Fashion an idea in your mind and stay with it until you are happy with the results. Using earth and water and the plants available to you, bring them all together, as you see fit. Before you know it, you have created something very real: a garden.

Robb Rosser is a WSU-certified master gardener. Reach him at Write2Robb@aol.com.