Extension Master GardenerSM Volunteers of Buncombe County

shrubs

Time to Maintain: Pruning Evergreen Shrubs

Do you have boxwoods, cherry laurels, or other shrubs with evergreen leaves in your yard or landscape? Late winter and early spring are the best times to prune these and many other leafy evergreens in your landscape.

Aucuba (Aucuba japonica), boxwood (Buxus sempervirens), cherry laurel (Prunus laurocerasus), and osmanthus (Osmanthus sp.) are a few of the many shrubs grown for their evergreen foliage rather than their blooms or fruit. Often serving as foundation plants and hedges, such shrubs have a variety of leaf shapes and leaf variegation (different colors in the same leaf) that make them welcome in the winter landscape.

Do you need to prune?
Although the title of this blog post is “Pruning of Evergreen Shrubs,” of all the plants in your landscape, evergreen shrubs require very little annual pruning! They grow into desirable forms by themselves and only need an occasional helping hand from you. When you do prune, keep the following in mind:

  • Always carry a sharp pair of hand pruners in your hand or a leather scabbard on your belt when working with the evergreen shrubs in the yard.
  • Be on the lookout for dead or broken branches and remove them promptly.
  • Remove any branches that are crossing over each other as they can rub the bark and make the plants more susceptible to infection.
  • Prune back branches that are growing onto driveways, sidewalks, and patios. When pruning, be sure to cut back to a branch or node that is pointing in the direction that you want it to grow.
  • When you shear hedges, remember to leave the bottom of the plants a bit wider than the tops to get light to the lower limbs, keeping them lush and green.
  • Prolonged use of electric hedge shears will result in a very small veneer of leaves just on the outer surface of the plants. If part of a continually sheared plant dies, the inner leaf buds will not develop and you will be left with a “hole” in your hedge. Take a look inside your hedge, and if you do not see leaf growth along the inner branches, you need to seriously consider using hand pruners to thin out portions of the plant canopy so light gets into these inner areas and the secondary buds have a chance to develop.
Topiary at Pearl Fryar Topiary Garden, Bishopville, SC
Topiary at Pearl Fryar Topiary Garden, Bishopville, SC

Some of these plants (such as boxwood or Japanese holly) can be pruned into fantastical shapes in topiary form. Plants shaped this way bring to mind animals, ships, and buildings. Forming plants into topiaries requires a tremendous amount of time and pruning effort to maintain their shape—almost constantly pruning off the stray branch or leaf—but the reward is a uniquely personal landscape.

 Cultural considerations
Evergreen shrubs are relatively disease- and insect-free and can be remarkably winter hardy. The fact that these plants keep their broad leaves throughout the winter, however, makes them particularly susceptible to winter desiccation and damage. You can avoid this by choosing the correct varieties for our area—pay strict attention to the hardiness zone when purchasing shrubs. Western North Carolina is generally in the USDA Hardiness Zone 6 or 7. Keeping a layer of mulch around the base of these plants will help to conserve moisture and minimize winter damage.

Caution! Know your shrubs!
Now is NOT the time to prune evergreen shrubs that you grow for their flowers! If you are uncertain, the Extension Master Gardener volunteers of Buncombe County can help you identify the plants in your landscape.

  • In general, shrubs blooming before June bloom on old season’s growth and you should prune them directly after blooming. Examples of plants in this category include azaleas and rhododendrons (both are Rhododendron spp.), as well as Japanese camellias (Camellia japonica) and mountain laurel (Kalmia latifolia). We will discuss their care in a future blog post.
  • Shrubs that bloom later in summer—such as hollies (Ilex spp.) and Pieris spp. (commonly known as andromedas or fetterbushes)—bloom on new growth so you can prune them before growth begins in the spring.

Article written by Bob Wardwell, Extension Master GardenerSM Volunteer.

Learn more
The Art and Science of Pruning
by N. Jordan Franklin, Consumer Horticulture Agent
Clemson Cooperative Extension

Pruning Trees & Shrubs: General Pruning Techniques
by Barbara Fair, Lucy Bradley, and Anthony LeBude
NC State Extension Publications

Fall Arrived on September 21. Get Ready to Plant!

Regardless of the thermometer reading, fall is in our future! With fall comes the best time for planting many woody—as well as herbaceous—perennial plants. Plus, nurseries often have fall sales to move their existing stock.

Keys to successful fall planting
If you find plants you like, you might think: “Where can I put this particular plant?” A better question is: “What plant best fits my landscape scheme for this spot?”

  • Before you buy have a site in mind.
  • Be sure that spot meets the desired plant’s requirements for sun, moisture, and nutrients.
  • Know how much space the plant needs and how quickly that plant will spread. Don’t bring home an invasive “Backyard Bully”!
  • How about the soil pH? A soil test will tell you if you need to lime or add any nutrients.

The results of a soil test may change your mind. Consider choosing plants that will match the site characteristics. 

Woody plants have additional needs
Trees—and even large shrubs—need special attention to their future size. Pruning may not be a viable answer to a tree that is shading too much of your homestead or threatening a power line, or a shrub that’s blocking a view. Consider how the planting will work in all four seasons. And think about how your placement will affect your neighbors, too. You can’t call in a moving company to cure a poor decision if your planting outgrows its space.

Are you prepared to do your own planting?
When looking at a woody plant you intend to plant yourself, consider the size, shape, and weight of the root ball. How is the root ball contained or restrained? You’ll need to remove that container or restrainer during the planting process, so be sure you have the appropriate tools. It is best to discard burlap or wire that may restrict future growth. 

Roots
Before you plant, examine the root ball. Are there broken or circling roots? Many horticulturalists recommend carefully washing off the planting medium to correct any root problems before planting. At a minimum, remove circling or broken roots and then score or cut through the root ball to encourage root growth. For more information about root systems of woody plants see: http://gardenprofessors.com/little-ball-of-horrors/  

Planting and irrigating
Backfill with the soil you removed when you dug the planting hole, and water as you fill. Tamp the soil gently; you don’t want to compact the soil, just put it in contact with the roots. Roots will continue to grow all fall and winter as long as the soil is not frozen at their level, so keep the root ball moist.

Mulching
Finish by spreading mulch over the root ball. Not only will mulch retain moisture, but the mulch “blanket” helps maintain a stable temperature, so that a surge during a warm spell won’t cause the plant to prematurely break dormancy. But don’t mound mulch around tree trunks or shrub stems.

Pick a cool day and enjoy the exercise.

Article written Glenn Palmer, Extension Master Gardener Volunteer.

Scorch Affects Woody Plants; Can Come from Too Much Water

Many of our landscape trees are now showing symptoms called scorch, a burnt, browning or discolored look of the foliage, sometimes accompanied by wilting of the petiole or leaf stem. This may be confined to one part of the tree or appear over the entire tree. Often the browning, discoloration or curling starts at the tips or margins of the leaves.

leaf scorch
leaf scorch

These symptoms can have a biotic (living) cause such as a bacterial scorch disease, or can result from an abitoic or cultural problem. Cultural situations may result from drought, soil toxicity, air pollutants or flooding and often come on later in the summer to early fall with uniform browning of the entire canopy or exterior leaves such as we’re seeing now.

This year (2013), we can attribute much of this decline to our excess rainfall. The tree or shrub is essentially drowning. What’s happening is that the soil has been so wet for so long that oxygen has been in short supply. This would happen particularly to trees that were deeply planted or planted in compacted soil, perhaps even many years ago.

So what to do now?  Clean up those leaves when they do fall; keep your fingers crossed and let’s see what develops next spring. If the plant is in otherwise good health it should recover.

Article written by Glenn Palmer, Extension Master Gardener Volunteer.

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Buncombe County Extension Office
49 Mount Carmel Road
Asheville, NC 28806
Helpline 828-255-5522

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