Add Shrubs for Diversity in Your Garden
Learn how to choose and care for shrubs that fit your garden conditions.
Most hardy shrubs need very little care once established, making them ideal for those with little time to spare. Tender types require more attention, but when grown in pots they can be easily moved indoors for the winter.
Their sheer diversity makes shrubs a highly appealing group of plants, but before you buy, check the labels carefully for final heights and spreads because different species can have widely differing habits. Azaleas are a case in point, with the deciduous Rhododendron luteum, for example, growing to a lofty 12 feet (4 m) in height, while the compact evergreen Rhododendron ‘Rosebud’ reaches no more than 3 feet (90 cm).
Look for healthy plants that show no signs of disease on the leaves and stems, and slip them out of their pots to check that the roots are not congested, since this will hinder their development once planted. Also reject any that have poor or underdeveloped root systems. Thoroughly check for signs of pests and diseases before buying your shrubs.
Shrubs for Different Conditions
To guarantee the best performance, choose shrubs that suit your site and soil; in the wrong conditions their foliage and flowers are likely to suffer. As well as checking plant labels, also consider shrubs’ native habitats. Those from warm climates like the Mediterranean need a sunny location in free-draining soil and often have small leaves that deflect the heat and light. Forest or woodland natives are shade lovers and can be identified by their larger, dark green foliage, which is perfectly adapted to absorb the low light beneath tree canopies. Check that shrubs do not require specifically acid or alkaline soils before buying to prevent an expensive mistake. Most shrubs will tolerate both, but there are some exceptions. Consider these conditions before choosing your shrubs:
- Sun: Shrubs with small, silver or gray-green leaves, such as rock roses (Cistus), lavender, and Russian sage, need a sunny site. Plants with colorful leaves, such as Berberis thunbergii and the purple forms of smoke bush also thrive in sun
- Shade: Many large-leaf and some pretty flowering shrubs, such as hydrangeas, prefer a shady site. A few variegated shrubs, such asElaeagnus, also cope with shade but need a little sun to bring out their colors.
- Acid soils: Some shrubs, such as camellias, rhododendrons, and Pieris, are only happy if grown in acid soil. Others that prefer acidic conditions include witch hazel, heathers, Enkianthus, Leucothoe, and Arctostaphylos.
- Alkaline soils: A greater number of plants will tolerate alkaline conditions, including sun lovers, such as Ceanothus, Cytisus, and Hebe, and plants for shade, such as Deutzia, Buxus, and Viburnum tinus.
Using Small Shrubs for Edging
Diminutive shrubs make excellent edging plants, either clipped to form a low hedge, or planted in a line at the front of a bed or border.
Thymes are useful edging for sunny, formal, or wildlife gardens, where their flowers will attract many beneficial insects. They are available in a variety of colors and look attractive when used to cover slopes and banks, especially when planted in colorful blocks. Consider combining them with other herbs, such as lavender.
Excellent choices for low, formal hedges or as edging for a potager include box, Buxus sempervirens, and forms of Euonymus fortunei; their linear structure lends them to traditional garden designs.
On acid soils, include heathers and heaths to form a dense carpet of evergreen, needle-like foliage. They naturally form domed shapes and can be clipped to accentuate this trait. Line up plants, use them in clusters, or plant in swathes for a natural effect. Different types flower in fall, winter, spring and summer, and by mixing and matching a range you can create an edge with flowers all year round.
Planning a Shrub Border
Many shrubs produce a dense thicket of branches and form a block of solid color, so arrange them in height order, with the smallest at the front. Also select plants with different heights and structures, and think of them as living sculptures to create a visually exciting display. For example, you could use a Cornus controversa ‘Variegata’, with its horizontal flowering stems, behind compact shrubs with contrasting straplike or rounded foliage.
You can also enhance the interest of some small-leaf shrubs, such as box or shrubby honeysuckle (Lonicera nitida), by clipping them into topiary shapes. Try planting a prized specimen in a large pot, and set it at the front of, or within, your border. Also consider shrubs with decorative or unusual foliage to inject textural and color contrasts, and add grasses, sedges, and perennials, such as rudbeckias or asters, to bring flowers and color to your border in the late summer and fall when few shrubs are in bloom.
On the other hand, architectural shrubs, such as clipped bay, palms, and fatsias, make excellent container plants. However, large shrubs or those in weighty containers can be very heavy, so it is wise to plant them in place or set them on plant trolleys, which can be wheeled around your plot with ease. You can buy decorative cast iron trolleys that make attractive additions to a patio display.
Caring for Shrubs
Many shrubs require very little aftercare, but they will need regular watering until their roots are fully established. Water during the growing season from spring to fall; evergreens may also need watering during prolonged dry spells in winter. Once established, most shrubs will only require extra water during a severe drought. Mature shrubs should not need feeding, either—just lay a mulch of well-rotted organic matter, such as manure or compost, around them each spring. If your plants are looking unhealthy or if your soil is poor, apply an all-purpose granular fertilizer before mulching.
Overwintering Tender Shrubs
Many tender shrubs, such as Cordyline australis, will not survive a harsh winter unprotected, but this should not deter you from growing them. The easiest solution is to grow compact types in small pots and bring them under cover during the winter. If your plants are too large or your pots too heavy to move, cover them with a double layer of horticultural fabric. Make sure you also wrap up the container to insulate the roots, especially if your plants are in terra-cotta pots, which may crack in cold conditions.
Alternatively, make a cage around shrubs planted in the ground, using chicken wire attached to canes. Pack the cage with dry straw for insulation, and cover it with plastic to keep out the rain. This method should keep the plant dry. Remember to remove the plastic on warm days to prevent the plant from “sweating” and rot from setting in. Frost-proof delicate roots by insulating outdoor containers with burlap or fabric.