April 23, 2008  
Shrubs Need Rejuvenating Now and Then, Too!

And now is a great time to give them that helping hand. Overgrown scraggly shrubs become an eyesore as well as a deficit in the landscape because their productivity is greatly reduced. It might be a high bush blueberry, a rose of Sharon, a lilac, a hydrangea, or a spirea. If you're lacking the abundance of flowers or fruit you once had, you can renovate your shrubs and bring them back to full productivity.  

A shrub is a perennial with hard, woody, long-lived stems often having some low stems branching near the ground. They also are called bushes, when they have very many branches. They are useful as cover and food for birds and game, and as protectors of the soil from erosion. Shrubs are popular as ornamental plantings in gardens, and as focal points in lawns. Some are employed as hedges and border definitions. Many shrubs produce fragrant blossoms. Others provide handsome, decorative and useful leaves, twigs, and fruits.  

We prune shrubs for more reasons than we generally think about. We prune to invest in the future of the plant. The question here is to the order of these priorities that most meets the needs of the owner/grower. We prune: to maintain health; to control growth and appearance; to encourage or improve yields of flowers, fruit or foliage; to create a special form for specific use (hedge, windbreak, etc.).  

When pruning to maintain health, we should remove damaged and diseased branches as soon as we see them. How did they get damaged? The usual suspects are insects, animals (deer and rabbits, especially), weather related events (snow load, ice), and even machines (weed whackers and lawn mowers). Regular pruning to correct these problems tend to keep shrubs more vigorous and better able to resist such environmental insults.  

Pruning to control growth and appearance enables the shrub to avoid growing into an awkward shape that might otherwise spoil its appearance and weaken it. Shrubs left untended for even short periods of time can quickly become that scraggly looking member of the landscape that looks overcrowded with branches, unattractive, and in danger of becoming unhealthy and dying at a young age.  

Shrubs that are in the landscape for the express purpose of producing blossoms for cutting, or for fruit production and harvest, or for foliage to be cut and displayed will all benefit from periodical proper pruning to suit those ends.  

Shrubs planted to serve as hedges or boundary markers can be kept low, well shaped and attractive with only a modicum of attention each year.  

Here are a few ground rules to remember: A moderate annual pruning is much better for the shrub than severely cutting back every five or six years. Never remove more than one third of a plant's leaf producing branches and stems in a single year. That is the principal key to food manufacture, survival and flourishing.  

If you have a shrub that is old, overgrown and in need of extensive renovation or thinning, this is best accomplished by willingly (if reluctantly) removing the elderly members of the plants' stems and accompanying branches to favor the energetic young stems filled with promise. Do this in early spring. Use clean and sharp tools like a lopper, pruning shear and pruning saw.  

First remove dead, diseased, deteriorating or broken stems and branches. Cut as close to the ground as possible some of the oldest, thickest, vertical stems. Remember the one-third rule above. Where branches cross one another, remove the lower to prevent rubbing, and to allow more air and light to penetrate the plant.  

Let's assume for a minute that you decide to replace a section of lawn with some ground covers to unite a few unrelated trees or shrubs that are at the moment isolated. The beauty of groundcover plants is that once they are established they require almost no care other than the occasional irrigation in a drought. There is a wide variety of forms, colors, textures and heights to choose from.  

In shrubs that are very overgrown, split up the renewal over a few years. By the third or fourth year it will be back to scale and producing like it hasn't in ages. This is especially useful for lilacs and high bush blueberries.  

Flowering shrubs that bloom on year-old wood already have their buds set and will bloom when the timing is just so. Forsythia is an early flowerer, usually in May. Pruning it now would remove many of this year's flowers. It's okay to prune it now, but most would wait until after flowering. This is also the case for Andromeda, Beauty bush, Daphne, fountain Butterfly bush, Honeysuckle, Lilac, and even some evergreens such as Rhododendron and Azalea. Prune immediately after flowering for next years best display.  

Prune shrubs that bloom on new wood as soon as practical. Late winter or early spring will stimulate these plants to produce lots of vigorous new growth, and you'll have a nice showing later in this year. This includes Abelias, Buddleia davidii, Callicarpa, most Hydrangeas, summer blooming Spireas and Hibiscus among some.  

Roses are divided into two groups. Group 1 includes ramblers, shrub and wild roses. All of these bloom on new wood. Shrub and wild roses can be cut back hard, to a foot and a half. Ramblers, which have more thorns and tend to trail over the ground, should only be cut back to three feet.  

Group 2 roses are the climbers, hybrid teas, tree and floribunda roses and all of these flower on old wood. Yet, for these, pruning is best done in the spring. Remove any dead canes as soon as spotted as well as any winter injured stems. Don't cut back too hard, because these do not bloom well on this current year's new growth. You're pruning to preserve the best year old wood for blooming. Thin out the canes to allow light and air.  

Occasionally, roses, too, need renovating. Removing old stems is the first step to bringing back overgrown bush and climbing roses. Cut them close to the ground. Remember the one-third rule. Reduce the height of the younger canes by a fourth to a third.  

Finally, I must say a bit about needled evergreens. They're shrubs, too. In general, they don't require pruning except in the cases where they are sheared into special shapes (topiary anyone?) or kept deliberately small. As with all shrubs, dead branches should be removed as soon as noted. Any other pruning or heading back should be done when the shrub is not growing, that is, when it is truly dormant. Shearing an evergreen should begin when the plant is young, should continue annually, and the plant will gradually grow larger and in the shape you desire. Shearing should only be done is late spring or early summer so new growth has sufficient time to harden off before winter. Hemlocks and yews might receive a few shearings up to mid-summer.  

Blueberry is a lot like lilac when it comes to pruning. Plan on renewing every few years. One-inch diameter canes are probably eight years old and should be cut out. Each year, remove the older, thicker canes and you'll boost productivity. Early spring is the preferred time to do this.  

Currant, Elderberry, Gooseberry and Juneberry all rely on a similar treatment. Get to know your plants and any wood that is older than three years, remove it close to the ground. Thin out any branches that remain that crowd the others. Spring is the time for this renewing pruning.  

Raspberry, Blackberry and Dewberry shrubs are a little different. In late summer or early fall, any canes that bore fruit should be cut to the ground and removed or burned to prevent any disease from overwintering. Thin remaining canes to six or so inches apart. Cut out very small thin canes. Remaining canes should be cut back enough so they stand stiff and upright, a foot or more is good. Do this before winter.  

If you feel you need rejuvenating from time to time, think about some of your plants. Hopefully, you had a bit this winter or this past year. Maybe, now, it's their turn.  

Good gardening is very simple, really. You just have to learn to think like a plant.
                Barbara Damrosch

Note: In my April 9th column, I recommended applying Tanglefoot to a TV antenna to keep a woodpecker from perching there and making noise with its beak to attract a mate. Reader, Doris Booth, an avian wildlife rehabilitator, advises me that this is bad advice and endangers the lives and well being of birds. I regret any harm this suggestion might have done.  

From The Garden of Ed. Submitted for publication in The Towne Crier on April 23, 2008

© 2008 Ed Mues. All Rights Reserved.