Shrubs are a very diverse group of plants. They have many uses in the landscape and, in my opinion, are greatly underused. Almost every yard has a few annual or perennial flower beds, but in a lot of cases, the presence of shrubs is absent.
There is no hard-set definition for shrubs, but generally speaking, a shrub is a woody plant with multiple trunks or stems that reach a height of fifteen feet or less. A woody plant continues growth each year from the ends of stems and branches and does not die back to the ground each year as do herbaceous plants (perennials). Trees may also have multiple stems or trunks (e.x. Maples, Birch, Willows, etc.), but their heights are greater than l5 feet at maturity.
A shrub that is trained to a single stem is called a 'standard', and is used for a formal effect in the landscape. These shrubs are referred to as miniature trees.
Deciduous or Evergreen
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Shrubs are either deciduous or evergreen. Deciduous plants lose their leaves in the fall and grow new ones in the spring. Lilacs and roses are examples. Evergreen plants remain green the year round and do not lose their leaves. Evergreens are either coniferous or broad-leaved. Coniferous shrubs are either needle like (spruce), awl-like (junipers), or scale like (some junipers and cedars). Kinnikinik (Arctostaphylos uva-ursi) is an example of a broad-leaved evergreen. Very few broad-leaved evergreens are hardy in zone 2.
Shapes And Forms
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Shrubs grow in a variety of shapes and forms which make them invaluable for the landscape. Prostrate forms grow horizontally and make excellent ground covers. These include plants like Junipers (Juniperus spp.), or Creeping Cotoneaster (Cotoneaster adpressus). Columnar forms are used for dramatic emphasis and include many of the Cedars, one being Thuja occidentalis 'Columnaris'. Weeping or cascading shrubs are used for graceful touches. Examples are Bridalwreath Spirea (Spiraea x vanhouttei) and Weeping Caragana (Caragana arborescens 'Pendula'). A great many shrubs are round or global in shape. Red-Osier Dogwood (Cornus sericea), Global Cedar (Thuja occidentalis 'Globosa') and Globe Caragana (Caragana frutex 'Globosa') are examples. Pyramidal forms are also used in formal plantings or hedges and include many of the Junipers. Juniperus scopulorum 'Blue Heaven', J. scopulorum 'Grey Gleam' and J. scopulorum 'Grizzly Bear' are examples.
Texture
When we speak of a plants texture, it is the visual impression left on us by the plant, whether by touch or sight. It may be smooth or rough, large or small, or light or dark. Texture may be described as a relative concept.
In summer, the leaf size, shape and pattern of the leaves produce various textures. In winter, texture is produced by the plants bare branches, stems, twigs and bark. They may be dark, coarse and bold, or light-colored, thin and delicate looking.
Coarse-textured shrubs appear bold, heavy, dark colored, large and tend to stand out. Most lilacs (Syringa spp.) with their larger, dark green leaves form a dense shrub and appear coarse in texture. Medium-textured shrubs are between coarse and fine and include shrubs that are more open and generally smaller leaved than coarse shrubs. Cotoneaster spp. and Spiraea spp. are medium-textured shrubs. Fine textured shrubs are generally light in color, small in size, smooth looking and appear lacy or delicate. Most Caragana spp. and Potentilla spp. are fine textured, for example. Fine-textured shrubs should be planted in front of coarser-textured shrubs when planted in shrub beds.
Color
When color in the yard or garden is mentioned, flowers automatically come to mind. However, there is a lot more color to shrubs than just their flowers. Leaf color alone provides many interesting colors. There are hundreds of different shades of green, including bright-greens and dull-greens, blue-greens, yellow-greens, gray-greens and the list goes on. 'Shubert' chokecherry (Prunus virginiana melanocarpa 'Shubert') has outstanding purple foliage. The small, dense, globular form of Colorado spruce (Picea pungens 'Glauca Globosa') varies in color from blue to silvery-green. Variegated (more than one color) leaves of some shrubs are striking. Cornus alba "Argenteo-marginata" (Silver-leaf dogwood) and Juniperus chinensis 'Pfitzeriana aurea' (Golden Pfitzer Juniper) are examples. Buffaloberry (Shepherdia argentea) has silvery colored leaves while Sea-Buckthorn (Hippophae rhamnoides) has grey leaves. Junipers offer a wonderfully wide range of greens, blues and silvers. The list of colorful foliage of shrubs is endless. Once fall arrives, the leaf colors change, adding even more dazzling and brilliant color to the garden.
When the deciduous shrubs lose their leaves, the stems of many shrubs add color to the winter landscape. These include bright reds, yellows, browns and greys, among other colors.
Persistent fruits and berries also add interesting color to a wintery landscape The bright red berries of high-bush cranberry (Viburnum trilobum) is one example.
Flowers and Fragrance
With proper planning and selection, shrubs can provide color from flowers from early spring until frost. Northern Gold Forsythia (Forsythia x hybrida 'Northern Gold) and Double Flowering Plum ( Prunus triloba 'Multiplex') start the show with yellow and pink blossoms in early May. Lilacs (early flowering), Honeysuckles, Spireas (spring flowering types), Caraganas and Elders follow with whites, mauves, purples, creams and yellows from mid to late May. In June, Dogwoods, Falsespirea, Lilac (late flowering species), Mockorange, Ninebark, Potentilla, Roses and Nannyberry start to bloom with a vast array of colors. Potentilla blooms from June till frost. Many roses are recurrent, that is, bloom a second or third time during the growing season to give an extended period of flowers. Scarlet Trumpet Honeysuckle, Potentilla, Hydrangea, Spirea (late flowering types), Roses and Tamarisk bloom from July to September.
Shrubs with fragrant blossoms include: Roses, Lilacs, Falsespirea, Mockorange and some Currant species.
Uses In The Landscape
Shrubs play an important role in the landscape. A single shrub may be used as a specimen plant simply to draw attention to itself. These plants have some special characteristics about themselves, such as their leaves, flowers, shape, color, bark or berries. If more than one or two are grown in close proximity to themselves, these special features will be lost. Try to keep it at one plant.
Noise Reduction
As with all plants, shrubs also absorb noise. The thicker the bush and the closer together they are grown, the better they reduce noise levels. A shrub bed or hedge located between the home and a roadway reduces noise levels from traffic significantly. In industrial areas, shrubs are a definite asset for reducing noise pollution.
Privacy
Shrubs may be used to hide your home from roadways or neighbors. In your own yard, you may want to separate an area from everyday traffic for sunbathing, as an example.
Wind Protection
Windbreaks or shelterbelts consisting of shrubs provide excellent protection from strong winds. They also help prevent snow from drifting into areas where it can be troublesome. Fruit trees, tall flowers and vegetables benefit from the shelter provided by shrubbery. Dust levels are greatly reduced in the yard, especially if one lives near a graveled or dirt road.
Living Screens or Barriers
Trash cans and compost bins are not very attractive objects. A more pleasant view would be flowering shrubs planted in front of them for screening purposes. Shrubs soften the outline of buildings and hide the unsightly areas like foundations. Areas of the yard may be separated by carefully planted shrub beds or hedges. The vegetable garden may be separated from the patio area, for example. The barnyard area or sewage lagoon is often separated or hidden from the house with a mixture of fragrant flowering shrubs.
Difficult Areas
Steep slopes that are hard to mow and rough areas are often planted to ground cover shrubs. Shrubs that spread by underground rhizomes should be chosen for these areas. Once established, they take over and require no more attention. They also act as a control measure against soil erosion. Examples include: Falsespirea (Sorbaria), Silverberry (Elaeagnus), Snowberry (Symphoricarpos), Sumac (Rhus), Some roses (Rosa), and Hazelnut (Corylus) to mention a few.
If you are tired of mowing vast areas of lawn, planting a mixture of native shrubs is the way to go. After a couple of years , there is no maintenance required as they maintain themselves. These native plantings provide homes, shelter, and berries for both birds and humans as well as adding natural beauty to the landscape.
A Few Simple Rules
When using shrubs in the landscape, keep balance in mind. A balanced landscape gives a feeling of relaxation, whereas, an unbalanced planting leads to confusion and wandering. Continuity is important. It is better to stick to a few varieties and locate them in different areas of the yard than to plant many different varieties all bunched together. The same shrubs grouped together make a strong design statement and look organized.
Always plant shorter shrubs in front of taller shrubs. It would be senseless to hide a beautiful flowering rose behind a large lilac shrub where it goes unnoticed. Background plants should have darker foliage and be of the type that form wide bases at maturity. Plants with lighter colored foliage and fine-texture should be set in front of darker ones. This will create a dramatic, pleasing effect that draws attention to the planting.
If you are the type of gardener that needs one of everything, try to locate shrubs with similar characteristics or textures in the same groups. This will present a more balanced effect. Remember that colors can clash. Take time to learn a little about your new shrub before planting it. When shrubs are placed correctly in the garden, they can be awesome.
