Boxwoods are a firm favorite amongst gardeners looking for a formal hedge or topiary specimen. Unfortunately, these fantastic plants are susceptible to some pest and disease problems and will do better with more attention than other plants.
Read on to learn more about growing and caring for these evergreens to decide whether they are the right plant for you.
What Is A Boxwood Shrub?
Boxwoods, or just boxes as they are sometimes called, are evergreen shrubs or small trees of the Buxaceae family. There are a large number of species, spread out across much of the globe, on every continent except Antarctica.
The largest species grow to over 40 feet (12m), although most plants in cultivation are small to medium shrubs. Most boxwoods have small, rounded leaves, which are arranged oppositely in all species. Young stems are angular and square in cross-section, which is probably the origin of this plant’s name. Alternatively, some say the origin of the plant’s name stems from a history of the wood being used in carpentry.
Boxwood leaf color is usually green, although some plants develop bronze tones in the colder months. The more winter sun the plants are exposed to, the more color they are likely to develop. The midrib of the leaves is very distinctive when viewed from below, showing up as a broad white line.
Boxwoods are a lot more popular for their form and foliage than for their flowers, although their blossoms are pleasantly scented. The flowers have no petals, are small and yellow-green, and not much to look at really. These plants bloom in the spring, with the flowers making way for small brown seed capsules.
Suggested Boxwood Species & Cultivar
Although there are over 70 described Buxus species, the following few are the most popular gardening subjects. Before selecting a cultivar for your garden make sure to fully research the growth rate, size, and hardiness zones of each.
Buxus microphylla – The little-leaf boxwood
This Japanese species is known for its small leaves and is popular as a bonsai specimen. There are several popular cultivars available in the horticulture trade. Some well-known examples include:
- ‘Sprinter’: A relatively fast-growing and upright form. It is ideal for low hedges.
- ‘Wedding Ring’: This is a variegated form with lime to golden leaf edges.
- ‘Winter Gem’: This boxwood reaches over 4ft (1.2m) tall and is best known for its rich bronze foliage that develops during the winter months in colder climates.
- ‘Golden Dream’: A compact form that reaches about 3 feet (0.9m) in height and has gold and green variegated leaves.
- ‘Green Beauty’: This is a tough form that is more resistant to heat, dry conditions, and humidity than other box plants. A good selection for low boxwood hedges and topiary.
Buxus balearica – Balearic boxwood
This species grows to about 10ft (3m) tall and nearly as wide. It is native to parts of North Africa and the Mediterranean. This species has an upright growth form and slightly bigger leaves than other popular species. B. balearica is adapted to warm climates and can be grown in USDA Hardiness Zones 8-10.
Buxus sinica – Korean boxwood
This East Asian species is popularly grown in borders, hedges, and containers.
- ‘Nana’: This is a very slow-growing plant that puts on just a couple of inches per year. It is a dwarf selection that grows about 2 feet (0.6m) tall and a little wider. New growth is lime green and darkens as it matures.
- ‘Wintergreen’: This cultivar is said to hold its color better in winter than other forms. It is a relatively fast-growing box plant.
Buxus sempervirens – common boxwood
This species is native to parts of Asia, Africa, and Europe. The wild species can grow to over 15 feet (4.5m), although it is a slow-growing plant.
- ‘Fastigiata’: This large Buxus makes an excellent upright hedge. The foliage is deep green and these plants grow fairly fast for a boxwood.
- ‘Graham Blandy’: This very upright form is ideal as an eyecatching architectural column specimen in the landscape.
Buxus harlandii – harland boxwood
This Chinese species is less cold-hardy than other options and grows well in zones 7-9. It shows good resistance to pests and diseases. This species has fairly narrow leaves and grows as a rounded shrub that usually reaches about 3 feet (0.9m) in height and width.
How To Grow Boxwood Shrubs
Boxwoods can be grown from seed but this is a very slow method of propagation and it will take many years to grow plants that are ready to be planted out. Cuttings are a better option and greenwood to softwood cuttings can be rooted from summer to early fall.
Bottom heat and controlled conditions undercover will produce better results. Some forms, like the common boxwood, can also be grown by the division of their root mass.
Boxwood plants have shallow root systems and can be transplanted with some care in the fall or winter.
Ideally, these plants should be spaced apart to encourage airflow. For dwarf varieties, this will mean a spacing of around 3 feet (0.9m). In order to grow a low hedge, however, you’ll probably want to space them a little closer.
These plants grow well in a variety of soil types, but they will do best in sandy loam with a neutral or near-neutral pH. The most essential requirement of the growing medium is that it is well-drained. Take care to observe that your intended growing site drains well before planting boxwoods because they do not do well in waterlogged areas.
Applying a layer of mulch will help to suppress weeds and maintain moist but not saturated soil around the root zone of the plant. Apply an organic mulch from a little outside the plant’s drip-line up until near the crown. The crown should never be covered in mulch as this will encourage rot.
In well-watered climates, these plants will need little watering. In dry environments, or until the plants are established and growing well, regular watering will be needed. Be sure to water well after planting or transplanting, and thereafter, be careful not to overwater.
These plants grow best in full sun to part shade in a site that is protected from cold, strong winds. Afternoon shade will benefit plants grown in very hot areas and will help minimize bronzing in the winter. Hardiness zones vary depending on the species and cultivar but there are options for zones 5-10.
Boxwood Care and Maintenance
Boxwoods are slow-growing, have moderate maintenance needs, and will need some attention from the gardener in order to do their best. Pruning to thin out will keep plants well aired which is a good preventative measure to guard against possible diseases. Make sure to sanitize your cutting tools before moving to a different plant.
In colder climates, prune them only after the last spring frosts to prevent any new growth being damaged by any unexpected cold snaps. Late spring pruning also encourages neater regrowth. In milder climates, pruning in late winter will get the plant ready for great performance in the spring.
Fertilizing, if necessary, can be done with matured manure or a balanced fertilizer. Be sure not to fertilize too late in the season as the new growth this stimulates can be damaged by cold before it gets a chance to harden off.
If you’ve grown your plant in an area that is exposed to cold harsh winds the leaves can dry out and bronze to brown discoloration can result. Setting up a windbreak or covering the plants in burlap or garden fabric can be helpful.
The box tree moth (Cydalima perspectalis) is an Asian insect that has invaded Europe and North America. The caterpillar of this moth is a serious pest of Buxus species that causes defoliation. It can be controlled by means of insecticides.
The boxwood leaf miner is a fly species whose larval stage can seriously damage the leaves of these plants. These larvae cause the leaves to swell up and die off. Other important invertebrate pests of these plants include the boxwood mite and the boxwood psyllid.
Buxus species are susceptible to some diseases as well, of which boxwood blight is the most serious. This fungal disease affects some cultivars more than others. This disease causes discoloration of the stems and leaves which progresses to serious defoliation and dieback that can kill young plants.
Boxwood Bush Uses
These plants are popular container and bonsai subjects but are most extensively used for short to medium hedges and architectural topiary. Boxwood hedges look amazing. They can also be grown as a border plant, foundation plant, or as a privacy screen. The brightly colored variegated forms can make great accent plants.
Buxus semperivens has a long history of medicinal uses for a variety of diseases and conditions, but these are not scientifically proven and therefore recommended.
Boxwoods are a great deer-resistant plant and their flowers are visited by bees and other pollinators.
If you’re looking for compact and tidy formal evergreen bushes for your garden, look no further than the boxwood shrubs. Bear in mind though that these plants do not produce showy flowers, they are slow growers, and they will need some maintenance in order to grow their best. Happy gardening!
*image by NadyaTk/depositphotos