Boxwood (Buxus sempervirens)

Boxwood, Common Box, Common Boxwood, European Box

The British native Buxus sempervirens, also known as the common box, is most frequently used for hedging and landscaping because of its lush growth and thin, evergreen leaves. Their green hue varies in intensity, becoming darker at the top and lighter at the bottom. 

I. Appearance and Characteristics 

Buxus sempervirens, the common box, European box, or boxwood, is a species of flowering plant in the genus Buxus, native to western and southern Europe, northwest Africa, and southwest Asia, from southern England south to northern Morocco, and east through the northern Mediterranean region to Turkey. Buxus colchica of western Caucasus and B. hyrcana of northern Iran and eastern Caucasus are commonly treated as synonyms of B. sempervirens.

Buxus sempervirens is an evergreen shrub or small tree growing up to 1 to (3 to ) tall, with a trunk up to 20 centimetres (8 in) in diameter (exceptionally to 10 m tall and 45 cm diameter). Arranged in opposite pairs along the stems, the leaves are green to yellow-green, oval, 1.5–3 cm long, and 0.5–1.3 cm broad. The hermaphrodite flowers are inconspicuous but highly scented, greenish-yellow, with no petals, and are insect pollinated; the fruit is a three-lobed capsule containing 3-6 seeds.

II. How to Grow and Care

Sunlight

Common boxwood likes sufficient sunlight but can tolerate partial shade too. Thus, it can grow well both indoors and outdoors. You can plant it almost anywhere, except for spots that are completely in the shade all day long. If it doesn’t receive enough sunlight, the leaves may turn yellow. There are other species in the Buxus genus that prefer low light environments, which are best grown somewhere with partial shade that avoids direct blazing sunlight in the summer.

Temperature 

Common boxwood is mainly distributed in temperate regions and prefers a warmer climate. However, it is cold-resistant to a degree, too. Common boxwood can grow at temperatures in the range of -23 to 35 ℃ but will become dormant and stop growing if the temperature goes outside of this range. If the temperature stays around 16 to 27 ℃, it will be vigorous and grow rapidly. It prefers moist soil but is also tolerant of dry conditions. However, it is not tolerant of waterlogging.

Watering

Common boxwood likes moist soil but is not tolerant of waterlogging. If its leaves turn yellow, you are advised to reduce the frequency of watering. During spring and summer, it grows exuberantly and requires timely watering. Water thoroughly each time.

If the weather gets too hot, water it twice a day, once in the early morning and once in the evening. In the fall, its growth will slow and the frequency of watering can be reduced. If it is grown in a pot, continue to water regularly, as the soil in a pot will dry out more quickly.

Soil

Common boxwood doesn’t require a specific soil type but does like the soil to be moist and fertile. It can even grow in dry and barren conditions. However, due to its intolerance of waterlogging, it is recommended to plant it in sandy soil with good drainage, rather than in clay soil.

Fertilizing

Common boxwood produces small flowers, so it does not require much fertilizer. It should be given fertilizer two or three times during its vigorous growth stage, at the same time as you water it. Use fully decomposed organic fertilizer, but don’t add too much.

Planting Instructions

It is recommended to plant common boxwood in the spring, so it has an opportunity to grow strong enough before winter comes. Also, the weather in spring is mild and warm, unlike in the summer when heat and drought could hinder its ability to adapt to a new environment. If you plant it in the garden, you should choose somewhere that receives 5-6 hours of sunlight each day, and soil that has good drainage. Water it immediately after planting. If the weather is very dry, you should continue to water it each day for three consecutive days.

If you plant common boxwood in a pot, it is best to choose a pot big enough to allow ample space for its roots to grow. Clay pots are the best option as they have excellent ventilation and help the roots to breathe. When planting, you can trim off any old or dead roots; this will stimulate the growth of new roots. In general, common boxwood should be re-potted every 2-3 years. It is advisable to do this before the budding of new leaves as their growth requires plentiful nutrition. You can also trim the roots when re-potting, and replace the soil.

Pruning

Common boxwood is very tolerant of pruning and tends to rapidly grow new twigs after it has been clipped. You can trim it into different looks depending on your needs. It is best to prune in the summer and winter. In summer, the plant is lush but the ventilation among the branches and leaves is not great, making it vulnerable to pests and diseases. In winter, it grows slowly and can maintain a certain ornamental look for longer. You can trim off any leaves that are old, dead, or have changed color, to make the plant look more presentable.

Propagation

Boxwood is best propagated by rooting from stem cuttings in midsummer. Here’s how to do it:

  • With clean pruning shears, cut 3- to 4-inch lengths of stem tips from new growth. Remove the lower leaves and scrape the bark from one side of the cutting.
  • Bury the ends of the cuttings in a pot filled with a mixture of sand, peat moss, and vermiculite. Moisten the potting medium, place the pot in a sealed plastic bag, and set it in a bright location.
  • Check the moisture daily, and mist whenever the cutting is dry. Check for roots every few days by tugging on the cutting.
  • When the roots are sufficiently developed, remove the pot from the plastic bag and transplant the cutting into another container filled with a rich potting mix.
  • Continue to grow the plant in a sunny window until outdoor planting time the following spring.

Potting and Repotting 

If you choose to grow boxwood in a container, opt for a container that is as wide as the boxwood is high. For example, if you have a 12-inch-tall boxwood, you need a 12-inch diameter pot. When it outgrows its current container, transplant it into one only a few inches bigger, keep the soil moist, and watch the plant for signs that it’s struggling—your soil might need to be amended.

Overwintering

In the northern part of the hardiness range, new growth is susceptible to winter damage. Protect the boxwoods with a burlap wrapping or similar protection during the first several years.

Pests and Diseases

  • Common Pests and Plant Diseases

Leafminer, boxwood mite, and boxwood psyllid are common pests. The damage is disfiguring but not fatal, and the pests can be treated with horticultural oils. In the deep South, nematodes are of concern. Boxwoods can be susceptible to fungal blights and leaf spot, and root rot can also be a problem in poorly drained soils.

  • Common Problems for Boxwood Shrubs

A common problem for boxwood is “winter bronzing,” a shift to reddish-brown or yellowish foliage color caused by winter exposure to wind and sun. One way to address the problem is to spray an anti-desiccant on the shrubs in late November and again in late January and to make sure your plants are watered sufficiently throughout the growing season. Also, you can build a structure around your bushes to shelter them from the wind and sun in winter. But some gardeners do not mind—and even actually value—the winter bronzing on the foliage.

III. Uses and Benefits 

The boxwood is identified with the Hebrew word תְאַשּׁוּר tə’aššûr oft-mentioned in the Book of Isaiah. Catholic households in climates where palms are scarce or nonexistant often use boxwood twigs instead to adorn their crosses on Palm Sunday.

  • Wood

Slow growth of box renders the wood (“boxwood”) very hard (possibly the hardest in Europe along with Cornus mas) and heavy, and free of grain produced by growth rings, making it ideal for cabinet-making, the crafting of flutes and oboes, engraving, marquetry, woodturning, tool handles, mallet heads and as a substitute for ivory; the wood is yellow in color. “Digging sticks” fashioned by Neanderthals more than 170,000 years ago in Italy were made from boxwood. The British wood-engraver Thomas Bewick pioneered the use of boxwood blocks for wood-engraving.

In Old English, a box was originally a receptacle made of boxwood.

  • Medicinal plant

The leaves were formerly used in place of quinine, and as a fever reducer.

Buxus sempervirens is a medicinal plant used to treat many diseases. It contains steroidal alkaloids such as cyclobuxine. It also contains flavonoids.

B. sempervirens was not known for its medical use until the beginning of the 1600s. After this it was found that the leaves (containing alkaloids, oils and tannin), the bark (containing chlorophyll, wax, resin, lignin and minerals) and the oil from the wood had a medical effect. It then was used to treat gout, urinary tract infections, intestinal worms, chronic skin problems, syphilis, hemorrhoids, epilepsy, headache and piles, but also had the reputation of curing leprosy, rheumatism, HIV, fever and malaria. For treating malaria it was used as a substitute for quinine, but because of the side effects and the fact that there are better medicinal alternatives than B. sempervirens it is normally not used any more to treat these diseases.

Homeopaths still make use of the leaves against rheumatism. While herbalists have used box leaf tea to lower fevers, it is very rarely used today.

In Turkey, where the plant is called Adi şimşir, this tea (one glass a day) is still consumed for antihelminthic, diaphoretic, and cholagogue purposes. Also, the leaves from B. sempervirens were used as an auburn hair dye.

The plant Buxus sempervirens has been well investigated chemically. During late 1980s, Dildar Ahmed while working on his PhD thesis under the supervision of Prof Atta-ur-Rahman, isolated a number of steroidal alkaloids from the leaves of the plant. A new system of nomenclature for buxus alkaloids was also proposed based on buxane nucleus. He also isolated a flavonoid glycoside, and named it galactobuxin based on the fact that it contains a galactose ring.

  • Garden Use

Common boxwood is one of the most common hedging and topiary shrubs across temperate climates. Its small evergreen leaves, tolerance of close pruning, and (subjectively) attractive scent make it perfect as a border plant. Common boxwood is frequently found in formal and Meditteranean-style gardens or at the front of people’s houses. Popular companion plants include other shrubs like hostas, thyme, or rosemary.

Boxwood (Buxus sempervirens) Details

Common name Boxwood, Common Box, Common Boxwood, European Box
Botanical name Buxus sempervirens
Plant type Perennial
Hardiness zone 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b
Growth rate Slow
Height 5 ft. 0 in. - 20 ft. 0 in.
Width 5 ft. 0 in. - 20 ft. 0 in.
Sunlight Full sun (6 or more hours of direct sunlight a day)
Soil condition Clay
Flower color Cream/Tan
Leaf color Gray/Silver