My spring project this year has been the new hillside garden. Mostly shade to partial shade, I think it would be pretty planted with a few Eastern Canadian Hemlocks, one of our most graceful native evergreens, and lots of rhododendron, don’t you? But no, no, no – the only thing it’d be in a year or two is “pretty” dead. When planting a garden all site conditions need to be taken into account – the amount of sunlight, moisture, wind, and what soil types are present. Although hemlocks and rhodos grow in shade, they can not handle the conditions in this particular garden: the wind, heavy soils and sand, and eventual inconsistent watering.
Landscaping is like building a house – you start from the ground up, and hopefully in the case of a garden, the foundation is composed of good soil. If not, don’t fret – even in poor soils, a garden need not be doomed to failure. The 300-and-something yards of soil we had brought in last fall to bury an old, crumbling and poorly built retaining wall, came from a construction site, and is very typical of the soil in this area – there was very little top soil. Here, it’s said if you don’t have clay, you have sand. The new garden is comprised of both; there are areas of heavy clay, and other areas are sandy. I’ll be working with what I have – I’m adding no topsoil or additional soil amendments.
I’ll also be practicing elements of xeriscaping; once established, most of the garden will receive little-to-no supplemental watering except what nature provides. Mention “xeriscaping” and many people wave their hands in dismissal, having a vision of a harsh, barren landscape of desert-type plants and rocks. Some of the misconception comes from the word xeriscaping itself. The “x” is pronounced as a “z,” which leads people to think “zeroscaping,” a term that is sometimes used as a synonym for a xeriscape, but one that is very misleading. Other terms synonymous with xeriscape are water-conserving landscaping, drought-tolerant landscaping, and my favorite, Smart Scaping.
With careful selection, the plants I introduce to the adverse conditions of this garden will thrive and provide a lush landscape not only beautiful, but environmentally sound once they are established. There are those words in italics again – “once established.” Few plants, if any, can be stuck in the ground to fend for themselves until they develop a root system strong enough to pull them through periods of drought. It could take one to two years before I can stop providing consistent water to this area.
The trees that frame the garden are already established. A large, mature maple provides most of the shade. An elm, a serviceberry, smoketree, a white spruce, and two clumps of river birch serve as a backdrop. When planning a landscape, work from large to small; after the trees, comes the shrubs – the bones of the garden.
I mentioned in a previous post that in the latter part of March, I moved two Michigan holly (Ilex verticillata), and starts from a yellow-twig dogwood, and ‘Henry’s Garnet’ Virginia Sweetspire (Itea virginica ‘Henry’s Garnet’), into the garden. Next came three big ‘Gro Lo’ Fragrant Sumac (Rhus aromatica ‘Gro Lo’), one of my favorite shrubs, and an excellent erosion control. ‘Gro Lo’ grows only about two feet tall, but spreads approximately six feet wide. Interesting chartruse-colored flowers appear in spring, and the fall color is gorgeous shades of oranges and reds.
The sumac were potted and easy to plant. Other additions included five bareroot Blue Muffin viburnum (Viburnum dentatum ‘Christom’). Viburnum dentatum is Arrowood viburnum, a native plant that gets its name because the straight shoots were used for arrow shafts by the Native Americans. Blue Muffin, which tops out at about five feet, stays shorter than the species form, and has dark blue berries that attract birds in autumn.
Bareroot trees and shrubs are generally less expensive than potted, or balled and burlaped plants. Check with your local nursery in the fall to order bareroot plants for early spring; they must be planted before they break dormancy. The roots should not be allowed to dry out; planting as soon as you get them is essential. If you’re unable to plant immediately, heel them in and keep the roots moist until you can.
When you’re ready to plant, soak them in a tub of water for fifteen minutes.
Once in the ground, water throughly. Using a solution of root stimulant will help ensure the success of your new plantings.
Mulching new plantings helps retain moisture, and suppress weeds. Two to four inches of mulch is sufficient. Always avoid the urge to build what is commonly referred to as “mulch volcanoes.” A mulch volcano is that cone-shaped mound of mulch piled high up the trunk of trees and shrubs. Not only a waste of mulch and money, mulching in this fashion can be deadly. The excess mulch is an open invitation to burrowing mice, insects, and fungus, which may feed on the bark of the tree. The volcano shaped pile inhibits water from reaching the roots; roots may also grow up into the thick layers of mulch instead of down into the ground, resulting in a tree or shrub with a weak, shallow root system. When mulching around plantings always be sure to keep the mulch at least six inches from the base of the plant.
Power companies and municipalities are excellent sources of free mulch; spring and fall is usually the time they do their tree pruning to keep branches away from power lines. I’ve had seventeen yards of free Consumer Power chips delivered for this garden. (I hope that’s enough; I’m sooo tired of shoveling mulch!) At between approximately $25 and $30 a yard if I’d purchased mulch, I’ve saved over $400 to $500! There is a downside to getting mulch from power companies – it’s not uniform in color or size, (there are some fairly good sized chunks in the batches I received), it’s not strictly hardwood, which is the most desirable mulch product, and it could contain poison ivy. I don’t really care what it looks like – I’ve always viewed mulch more for its functional abilities, rather than for decorative purposes. In fact, I really don’t want to see it – I’d rather it be there, doing its job unseen beneath a lush cover of plants.
There is one part of the garden that has fairly decent soil – loose, but not sandy. It’s also the least windy area. Here is where I chose to plant five boxwood – how could I pass them up; they were free last fall – and a Pink Diamond hydrangea (Hydrangea paniculata ‘Pink Diamond’). Hydrangea paniculata has white, cone-shaped flowers, and is hardier than the hydrangea macrophylla – the big mopheads with pink or blue flowers. Both the boxwood and hydrangea will require more consistent watering than the rest of the garden, but planted in the same area, less water will be wasted. Another element in xeriscaping is grouping plants with similar watering needs together, making watering more efficient.
After I got all these shrubs planted – twenty-one in all – the structure of the garden was beginning to take shape. Everything was still dormant though, and I was thankful for the relief from all that brown provided by the bright, cheery daffodils I planted in the snow last November.
Although hemlocks and rhododendrons would have been nice, I like the way the garden is shaping up. By choosing plants that will adapt to the garden’s condition, it’ll be a much more successful landscape than if I just planted what looked pretty. The success of any garden depends on knowing your site conditions – the types of soils, patterns of the sun, and amount of moisture in the area. Be realistic about how much work you are willing to put into the garden to maintain it. Taking these things into account, choose your plants accordingly, and experiment only with what you can afford to lose. And above all, learn to love what you can grow.
Next up: Perennials and groundcovers.
(Also, watch your July/August 2009 issue of GRIT for an article on xeriscaping! – Eds.)