By Pat Malcolm
Next to the landscape importance of trees is that of shrubs that grow in our gardens, parks, landscape foundation, street borders, and commercial landscapes. Thousands of different varieties of shrubs are grown to ornament lawns, yards, and borders, but only a few varieties are available to buy at your local nursery for planting, and growing. Many shrubs are selected and grown on a basis of intelligent buying of flowering hedges, evergreen cold hardiness, non-flowering hedges, berry shrubs, and deciduous shrubs. Many shrubs glow with brightly colored leaves in the fall and winter.
Evergreen shrubs often are planted to grow as a low ornamental hedge, such as: Juniper, Holly, Anise, Boxwood, Aucuba, Pittosporum, and Wax Myrtle. Large evergreen shrubs that, after many years of growing, are Arizona Cypress, Arborvitae, Thuja occidentalis, Thuja orientalis; Bamboo, Eleagnus, American Holly, Italian Cypress, Several tall Juniper cultivars, Leyland Cypress, Podocarpus, and Wax Myrtle, Myrica Cerifera. Some large landscape evergreen shrubs are planted as specimen plants, Bamboo trees, Italian cypress, Philodendron, Philodendron selloum, Philodendron x ‘Xanadu’, and Podocarpus.
Although it is common for some shrub stems to die from shading out, they will be renewed by new shoots; and like trees, shrubs live for years and are considered a good property, longtime investment, and a permanent fixture in the landscape.
Usually planting shrubs as privacy hedges will mature to a point in four to five years, that the privacy screen will be vigorously solid and dense enough to hide whatever lies behind it.
Some flowering shrubs being to bloom in late winter, such as the fragrant Tea Olive, Azalea, Camellia, and Ligustrum followed by the Abelia, Banana Shrub, Hydrangea, Red Bottle Brush, Bridal wreath, and Yellow Rose of Texas. Most shrubs finish flowering by mid-summer, when flower buds are formed to bloom next year.
Some shrubs thrive in dry soils; others in wet soils, but most shrubs and hedges fall in-between and require well drained growing areas. All other possible growing extremes are important for planting shrubs, and hedges such as altitude, shade, wind exposure, and soil relative fertility levels. Azaleas, for instance, grow well underneath the shade of most trees, including Pine trees, and will decline fast and soon die, if planted to grow in full sun. Azaleas must have organic matter incorporated into the soil to thrive, and the proper acidity (pH) of the soil is necessary for azalea plants to live. Pine straw is often effective to keep azaleas weed free. Long lines of blooming azalea plants are often dramatic when plant underneath pine trees, when the azalea flowers being to display their expanding blooms. The shallow root system of azaleas require substantial watering during dry spells to insure plenty of azalea flowers, the spring season following summer droughts.
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Small Evergreen Shrubs
Evergreen shrubs are an important choice to consider for planting, in order to insure green color presence during the gloomy days of winter. Many gardeners want an evergreen shrub as a hedge to maintain privacy when cold weather arrives. Anise, Illicium florianum grows into small hedges in resorts like Sea Island, Georgia, and exotic red flowers and liquorish aromas rise from the leaves in the summer. Acuba japonica variegata ‘Gold Dust’ is also called the Gold Dust plant. Acuba makes an interesting low growing shrub to plant and grow next to brick buildings. Cleyera, Ternstroemia gymanthera, is an interesting shrub for coastal areas, because Cleyera shrubs are very tolerant of salt water spray, and the waxy green leaves have a unique tropical appearance in the landscape. Boxwood, Buxus microphylla asiaticum, is also salt water tolerant with dense coloring throughout the zones 5 – 9. Boxwood is one of the most important and popular shrubs to buy in the U.S, notably as a neat, clean grower, Boxwood is not fast growing, thus requiring many years to reach 3 feet in height. Boxwood plants are commonly planted in rows along walkways. Larger boxwood plants work nicely in group plantings in front of buildings
Eleagnus, Eleagnus pungens, is one of the fastest growing shrubs and grows as a superb barrier hedge or privacy fence that can grow up to 10 feet tall. Eleagnus is salt water tolerant, and can be grown in containers at commercial locales. Interstate highway landscaping is filled with large groupings and plantings of Eleagnus, Eleagnus pungens, shrubs to minimize automobile fumes and truck highway noises.
Holly shrubs are distinctively varied, very adaptable, and versatile in the landscape. The most popular hollies are: Burford Holly, Ilex cornuta; Carissa Holly, Ilex cornuta ‘Carissa’; Dwarf Chinese Holly, Ilex cornuta; Dwarf Japanese Holly, Ilex crenata; Helleri Holly, Ilex crenata; Needlepoint Holly, Ilex cornuta ‘Needlepoint’; Sky Pencil Holly, Ilex crenata ‘Sky Pencil’; Savannah Holly, Ilex x attenuata; Stokes Dwarf Holly, Ilex vomitoria ‘Stokes Dwarf’; Dwarf Yaupon Holly, Ilex vomitoria; Weeping Yaupon, Ilex vomitoria pendula.
Japanese Aralia, Fatsia japonica, is most commonly called Fatsia. In landscapes, Fatsia is often planted and grown in large groups near shaded house entrances or underneath shade trees for that bold tropical look. Fatsia can be planted as a large specimen plant, or containerized Fatsia will grow as the shrub as an indoor plant. Philodendron selloum is often used like Fatsia, and can grow into a large, attractive specimen plant on slender, woody-looking trunks (stems). The Philodendron hybrid, Xanadu, is also used like Japanese aralia, Fatsia, and Philodendron selloum, but largely is used as an indoor or outdoor container plant. The waxy, deeply-lobed green leaves are very cold hardy, and even if Philodendron is growing outside in Zone 5 – 10, it will come back to life from vigorous roots in the spring after freezing to the ground.
Pittosporum tobira can be grown as an outside plant or as a containerized shrub. Pittosporum plants displays bright green leaves year and grows best in shady areas of low light. The flowers are small, white, and very fragrant, like the aromatic crushed leaves. Florists use stems and leaves as fillers in floral arrangements. Pittosporum shrubs are not fast growing, but eventually can form an excellent privacy hedge to block out automobile noise and fume emissions. Because Pittosporum tobira shrubs are salt water tolerant, these shrubs are popularly used in landscaping at Sea Island, Georgia. Large specimens of Pittosporum tobira are used as evergreen small trees, that subtly present an exotic, tropical appearance. Pittosporium tobira ‘Variegata’ has variegated white and light green leaves with fragrant white flowers, blooming in the summer. The variegated leaf form of Pittosporum tobira is not burned by strong sunlight, like most variegated shrubs.
Large Evergreen Shrubs
Large evergreen shrubs sometimes grow into small eclectic trees after many years. These large evergreen shrubs provide the garden with specimen attractiveness, privacy, and evergreen, cold hardy color. Arizona Cypress is also called Carolina Sapphire, Cupressus glabra ‘Carolina Sapphire’, and is a fast growing evergreen, that can grow 20 – 30 feet with fine textured, silver-blue leaves. The leaves grow threadlike in very hot areas, and will survive well in droughts or under stress.
Arborvitae, Thuja occidentalis, is an American native evergreen shrub that can grow almost anywhere in the U.S. The dark green leaves of Arborvitae, Thuja occidentalis, can turn yellow, orange, or maroon during winter, but the green color is restored in Zones of cold hard tolerance, 2 – 8, in the spring. Other arborvitae species are: Emerald, Thuja occidentalis ‘Emerald’; Little Giant, Thuja occidentalis ‘Little Giant’; Little Golden Giant, Thuja occidentalis ‘Little Golden Giant’; Aurea Nana, Thuja occidentalis ‘Aurea Nana’;
Blue Italian Cypress, Cupressus sempervirens ‘Glauca’, will qualify as one of the most important specimen, evergreen trees used in landscapes. The trees are not fast growing, but are cold hardy in zones 7 – 11. The dense leaves are branched and grow into a large column, 3 -4 feet wide. Italian cypress can grow to 40 feet outside, and large container grown Italian cypress trees can be shipped quickly on semi-trucks, or by UPS. Italian Cypress, Cupressus sempervirens ‘Glauca’ can draw architectural attention to large buildings. Italian cypress trees are often planted at commercial banks, bordering large walkways or memorial gardens.
Leyland cypress, Cupressocyparis leylandii, is a fast growing shrub, that most often is planted as a privacy hedge, but in many cases can grow into a large Leyland cypress specimen tree that might reach 130 feet. The Leyland cypress shrub (tree) is a fast growing intergenetic hybrid. Erosion control can be obtained fast by planting these vigorous Leyland cypress shrubs to embed their roots rapidly into the soil and cool the earth.
Podocarpus macrophylla and Podocarpus nagi are the most commonly grown shrubs of Podocarpus. Shearing Podocarpus is a common plant practice to create a sculptured look. Podocarpus can be grown as a border plant for walkways, but after many years, grows into a 10 foot, small, evergreen tree. The salt water and cold hardy tolerance of Zone 7 – 10 makes Podocarpus a top choice to buy for any landscape garden.
Wax Myrtle or Bayberry, Myrica cerifera, grows normally as a native American plant in forests, but nursery grown plants will provide a fast growing screen that spreads by underground shoots. Birds and wildlife love this plant for nesting and to seek protective cover. The waxy, gray berries are fragrant and commonly are used to scent candles with a woody aroma. All parts of wax myrtle shrubs are fragrant and grow to block out noise and noxious automobile fumes. Very old wax myrtle plants grow into exotic looking small trees, that are aromatic specimens in the landscape. Wax myrtle shrubs, Myrica cerifera, are a commonly-grown naturalized plant that enthusiastically is used as a salt water and cold hardy tolerant hedge or landscape tree at the famous resort hotel at Sea Island, Georgia.
About the Author: Patrick A. Malcolm, owner of TyTy Nursery, has an M.S. degree in Biochemistry and has cultivated various plants for over three decades.
Source: isnare.com
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