Garden Life: Trimming can revitalize rhododendrons

By Robb Rosser, Columbian Gardening columnist

Published:

 
photoRobb Rosser

Instead of tearing out that overgrown rhododendron, this may be the year to practice your pruning techniques. Established rhododendrons can be quite lovely plants, especially when trained as a small tree. Take the time to limb branches from the bottom up. Limbing simply refers to cutting the branches off with a pruning saw where they connect to the trunk or another main branch. Thin out higher branches for an open, airy look.

After pruning, plant a trustworthy ground cover such as variegated pachysandra at its feet. When adding plants beneath a rhododendron, it's best to do so along the plant's dripline. A dripline refers to the outer limit of a plant's branches and foliage. This is the point where rain would drop off the outer leaves and fall to the ground. Small rootlets on most trees and shrubs reach out to this point to take water up into the plant. Digging a hole too close to the plant's trunk will cut into the root system, which is close to the surface of the ground.

Unless your rhody is blocking a window or overgrowing a small space, it is usually worth the effort of pruning. You then have to live with this makeover for at least a couple of seasons. If you still like the look when autumn returns, you will find the open space around the rhody's perimeter to be a perfect spot for spring blooming bulbs. Small daffodils such as "Tete a tete" will find this situation quite to their liking. Another good groundcover would be dwarf Mondo grass. Its dark green, strap-like foliage grows in clumps and multiplies readily. Kyoto is cute, smaller than the species. Mondo grass is hardy and truly low maintenance.

Eye on color

Few things affect the overall look of a garden as much as color. When we describe a garden we've visited, we comment on the flowering trees or the wonderful daffodil meadow. What we see in our mind's eye are the colors. Used effectively, color can help invoke any feeling we choose. Most of us learn by trial and error. This is actually a fine way to learn, since the garden is a forgiving master. What we don't get right this year will not be held against us. Next year, spring will come back, bringing another chance to try again.

For the greatest color impact, think about how the colors of plants will blend or contrast with their surroundings. For example, you would not want to plant a red-flowering rose bush against a red brick wall or a redwood fence. Take the same background and plant a sweep of white azaleas instead. "Treasure" is an especially clear, bright white azalea. This combination of textures and color will add a great punch of contrast. Pink, peach and rose impatiens stand out well against the solid green backdrop of boxwood shrubbery.

To brighten a shady garden area, use light-colored annuals such as white, light pink or the palest blue and yellow pansies. Dark colors tend to get lost in shady areas. You can use plants with deep colors in a shady area if you provide partner plants with light-colored foliage. Surround the deep purple-blue-flowering Monkshood with plants known for their bright leaf color. This is particularly effective if the surrounding plants have large leaves. Brunnera macrophylla "Silver Heart" or "Sea Heart" from Skagit Gardens are good choices. Many of the newer variety coleuses carry splashes and splotches of light and dark color on every leaf, providing their own contrast.

Horizon of the garden

As interest in garden design becomes more sophisticated, we discover that a shrub is much more than a plant to wrap around the base of a house's foundation. Shrubs are the horizon of the garden. Placed in beds and mixed into borders, they relate the house to the garden and people to the house. At eye level, on a human scale, the shrubs surround, divide and enclose the spaces in which we live. Rising above the shrubbery are the rooftops of our houses, the trees and the sky. Below are the masses of groundcovers and grass lawns.

Used in groups, shrubs frame a view, divide a garden or serve as a backdrop for the bright, colorful flower display in a perennial border. Shrubs can be useful in dividing a garden into specific areas or rooms, as well as screening the garden from neighbors, an unsightly view or heaven forbid a neighbor's unsightly garden. Like a backbone, landscape shrubs add stature and hold the garden in alignment.

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