Shrubs for Difficult Garden Soil
The homeowner with a yard that consists of fertile, well-drained, loamy soil has the pick of almost any plant available on the market. Although this ideal soil type exists in prairie states like Iowa and Kansas, the majority of homeowners enjoy less than ideal soil structure and pH. Highly acidic, alkaline, sandy, wet, or clay soils limit a gardener’s plant choices, but there are plants that do well in tough situations. Following are some shrubs that can be used as hedges, for privacy, or as ornamentals that do exceptionally well in soil that would kill most plants.
Blueberry & Fothergilla
The homeowner living in an area with sandy, acidic soil has the opportunity to grow blueberries — one of North America’s most prized native fruits. Blueberries are very cold tolerant, with wild types growing in tundra conditions in the Northwest Territories of Canada. The cultivated varieties grow into neat, 4-foot-tall bushes that are excellent in borders or along a fence line.
In spring, the blueberry bush sports dainty white flowers. When pollinated, the flowers turn into delicious berries that ripen from mid-June through the end of September. After the first light frosts, the leaves of the blueberry turn scarlet red. Blueberry bushes need full sun, acidic soil, and regular watering through the summer in order to be at their best. For optimal fruit production, grow two or more cultivars, as the blueberry plant is not self-fertile.
A second shrub that enjoys acidic soil is the fothergilla, or witch-alder. This little-known bush enjoys slightly acidic soils that are high in organic matter. It prefers a partially shaded location with soil that remains moist, but not saturated with water.
Like its cousin, the witch-hazel tree, it bears fragrant white flower spikes that look like bottle brushes early in the spring, before the leaves emerge. In the fall, the leaves turn color, from bright orange to deep scarlet. Standard fothergillas grow 5 to 6 feet tall, while the dwarf varieties mature at 3 feet tall. Fothergillas are hardy from growing Zones 5 through 8, and can withstand the saline air found along the eastern coastline.
Mock Orange & Lilac
At the other end of the pH spectrum, there are two flowering shrubs that prefer soils that are slightly alkaline. Both of these shrubs bear highly fragrant flowers in the spring, and both make excellent specimen plantings or hedges.
The first is the mock orange (Philadelphus spp.) Growing from 6 to 10 feet tall, a well-tended mock orange is covered in citrus-scented single white blooms in late spring and early summer. The mock orange is a fairly low-maintenance shrub as well. It enjoys a trim after blooming, as well as applications of foliar “bloom booster” fertilizer during the summer. Mock orange shrubs are able to survive very cold winters, with temperatures as low as minus 30, as long as they’ve had steady moisture during the growing season and a solid mulch cover in the fall.
The second shrub that likes alkaline soil is the lilac (Syringa spp.) Lilacs are distinguished by two characteristics: their flower panicles that range in color from lavender to deep purple, white, and pink, and the hearty fragrance of those flowers. An excellent shrub for the cut flower fanatic, a small cluster of conditioned lilac blooms will fill the room with color and fragrance for a week or more. The common lilac (Syringa vulgaris) is a bit rangy for use as a hedging plant, but there are hybrids on the market that stay neat and compact while still retaining their flower power. Lilacs can be grown from Zone 3, all the way south to Zone 8, making them a versatile shrub.
Rugose Rose & Crepe Myrtle
If pH is not a problem, soil composition or texture may be. Sandy or thin soil heats up quickly, drains rapidly, and contains very few nutrients. Luckily, there are plants other than cacti that tolerate these conditions.
One such plant is the tough and thorny rugose rose (Rosa rugosa). Rugosa roses bear large, single, fragrant flowers once a year. The native rugose rose bears light pink flowers, while hybrids bear white, deep pink, and magenta flowers. The flowers are followed by decorative seed pods, or rose hips, which can be used in floral arrangements or dried for tea. Rugosas can grow to 6 feet tall, but do well with heavy pruning. They make lovely hedges, and the thorns deter stray dogs and people. They are hardy into growing Zone 2.
Gardeners located in growing Zones 7 through 9 who have sandy soil can enjoy the colorful crepe myrtle. This shrub is often referred to as a tree, because some varieties can grow up to 30 feet tall. However, there are dwarf selections available that are appropriate for foundation or container plantings. Crepe myrtle shrubs can be either globular or vase-shaped, and they bloom from July through September. The blooms come in clusters, and extend over a wide color palette that contains pure white, various shades of pink, scarlet red, and purple. Crepe myrtle doesn’t like heavy pruning, but if spent flowers are pruned off, the shrub will rebloom. In addition to their flowers, many crepe myrtles also have colorful foliage in the fall. The exfoliating bark on a few varieties adds visual interest during the winter months.
Redosier Dogwood and American Elderberry
Many homeowners in the Midwestern United States have heavy clay soil. Clay soil drains poorly and compacts easily. During droughts, it can bake into rock-solid adobe. Although it’s nutrient rich, the cation ratio makes it difficult for many plants to extract those nutrients. There are two shrubs that are easily grown, ornamental, and have a high tolerance for clay.
The redosier dogwood (Cornus sericea) is a fast-growing shrub that’s particularly suited for clay soil. It can reach 8 feet tall if left unpruned, but it tolerates heavy pruning well. Its leaves are green, brushed with white, and they turn gold or orange during the fall. The real show begins after the leaves have dropped. Redosier dogwood stems are a bright, fire-engine red. A small thicket or hedge of redosier dogwoods create a stark contrast to winter snow and can brighten even the gloomiest January day. Redosier dogwoods are an excellent choice for areas that have short growing seasons as well. They can withstand winter temperatures as low as minus 50, as long as they’re well-mulched.
A final option for clay soil is the American elderberry (Sambucus canadensis). Often found growing wild along abandoned railroad beds, the American elderberry has a high tolerance for clay soil that stays damp. The bushes are hardy from growing Zone 3, south to Zone 8. In late June or early July, the vase-shaped shrubs are crowned with white blossoms that attract butterflies and honeybees. Dark clusters of edible purple berries follow in late summer.
Elderberries can be used in jams, jellies, wine, and pies, and are also considered a “super food,” as they contain a higher concentration of vitamin C than an orange, and are rich in antioxidants. There are elderberries that have been hybridized specifically for fruit production; “Adams” and “Johns” are popular hybrids and should be planted with one another to optimize productivity. Elderberry bushes can grow up to 10 feet tall, making them great privacy hedges.
Homeowners with less than perfect soil can take comfort in the fact that there are ornamental shrubs that will not only survive, but will also add beauty, privacy, and color to the garden. All of these shrubs are easily purchased through online nurseries or at local garden centers.
Your local county extension office can also provide you with tips and tricks for success in planting, as well as in working with soil conditions unique to the local area.
It Was Ground This Morning
Acid-loving plants, using coffee grounds in the garden, and the great coffee grounds pH debate.