Broadleaf Evergreens Add Distinction
Broadleaf Evergreens Add Distinction Broadleaf evergreens are ornamental plants with comparatively broad or wide leaves that remain green
throughout the year. Some of the most attractive plants for landscape beautification are found among the broadleaf evergreens. Many of these plants can and should be used in northern landscapes. At the present time, too few are found even in areas where they can be planted successfully. Rhododendrons, including azaleas, are the most spectacular of this group of plants. Their magnificent floral displays in late May and early June are a sight to behold, and their rich, broad evergreen leaves add interest to the landscape throughout the year.
Holly is a must for gardeners of distinction. The blue holly cultivars produce bright red berries for the fall and Christmas season. It must be remembered, however, that only the female holly plants produce fruit. Male plants must also be grown for pollination and fruit production to occur. The dark bluish-green, spiny leaves of the blue holly produce interesting patterns in form and texture. The smaller leaved Japanese holly is excellent for foundation and low hedge plantings. Its bright, shiny evergreen foliage is most pleasing to the eye, particularly when the leaves glisten in the sunlight following a rain.
The evergreen euonymus is available both as a ground cover and a shrub and has leaves in many sizes with considerable variation in marginal variegation (two- and three- tone leaf color). The boxwood is a good choice for formal clipped or informal evergreen hedges and foundation plantings. In most cases, boxwood looks better when it is allowed to grow unclipped in a natural fashion.
Broadleaf evergreens can serve the landscape in many ways. They can be used in shrub borders and foundation plantings, and the larger plants make excellent specimen plants. As ground covers, broadleaf evergreens offer one of the most extensive uses of all evergreens, broad or narrow. Periwinkle (Vinca minor) has been an old standby for years, as has Japanese spurge (Pachysandra terminalis). The hardy selected cultivars of English Ivy (Hedera helix) can also be used if they are not subjected to south and west exposures that are completely open. These ground covers can be grown in sun or deep shade as long as they do not have to compete with a competitive root system such as that of a Norway maple. Broadleaf evergreens tend to look their very best when used in naturalistic plantings with a few deciduous shrubs and trees for contrast.
To grow healthy broadleaf evergreens in northern landscapes, the gardener must select the right site and then practice a few simple cultural techniques. Because these plants are evergreen and their leaves are broad, the site should afford the plants good protection from the sun and wind. This is particularly important during the winter, when exposure to the wind and warm rays of the sun would cause the leaf temperature to rise and moisture to be lost. Excessive moisture loss from the leaves, or desiccation, will result in death of leaves, stems or the entire plant. Many broadleaf evergreens can withstand the cold temperature (down to -20 F) of most winters in the southern portions of zone 5, provided they acclimatize slowly during the fall. They are most commonly injured by rapid changes in temperature. A good site for the tender members of the broadleaf evergreens is in the north shadow area of a building, fence or planting of large, narrowleaf evergreens, such as pine, hemlock, spruce and fir.
Soil for most of the broadleaf evergreens should be of the organic type. Avoid heavy and poorly drained clay soils. Although the plants like moist soil, they do not tolerate having their roots too wet. Therefore, the site should be well drained. If the soil is not organic, remove it to a depth of approximately 2 feet and replace it with a mixture of sphagnum peat moss, aged bark and sandy-loam topsoil (l:l:l by volume) that has a pH reading of 4.5 to 5.5 (acid). The roots of rhododendron are very fine and do not grow well in a clay soil, nor do they function properly if the soil is alkaline. Do not plant too deep. Notice the original soil line on the stem of the plants and use this mark as a guide for proper planting depth. If you plant in the l:l:l (peat:bark:topsoil) back-fill, set the plants a bit higher (mound up the bed) to allow for shrinkage and settling. Many broadleaf plants grow naturally with shallow roots, and roots planted too deep will suffocate.