Buxus sempervirens L.
Buxus sempervirens, commonly known as Boxwood, Common Box, is a dense shrub with glossy dark-green leaves.
- 1 Naming
- 2 Taxonomy
- 3 Characteristics
- 4 Distribution
- 5 Cultivation
- 6 Uses
- 7 Maintenance and Propagation
- 8 Varities and Cultivars
- 9 Poisonousness
- 10 Pests and Diseases
- 11 Man and Buxus
- 12 Literature
- 13 Non-commercial Links
Buxus sempervirens was described in 1753 by Carl Linnaeus. The name is considered as validly published.
The shrubs are dense and reach heights of 2 to 4 metres and often the same in width. Var. arborescens may grow to be a small tree with a max. height of 8 metres. The plants are very long-lived and may be a few hundred years old.
Wood and Bark
Young shoots are green and tetragonal, later the branches are rounded with greyish-brown bark.
Buxus sempervirens is evergreen with simple, leathery leaves that are arranged alternately along the stems. The leaves are ovate to elliptic with entire margins. They are 1,5 to 3 centimetres long and are glossy dark-green above, lighter green below.
Flowers and Fruit
Boxwood is monoecious with small, inconspicuous yellow-green flowers in March and April. The flowers sit in clusters in the leaf axils.
The plants produce capsules that are 7 to 8 millimetres long. The capsules have three compartments that each have two "horns". The fruits ripen from August to September and contain glossy black seeds.
Buxus sempervirens has a dense, cordate root system that grows both deep and wide.
Buxus sempervirens is native to Southwest and Central Europe, North Africa and West Asia. It's original distribution ranges from the Mediterranean to France and South Britain and to Northern Iran. The European core areas are North Spain to Southwest France on the one hand and the Balkan Peninsula on the other.
Box has been used both as an ornamental and a useful plant for a long time so that it can sometimes also be found naturalized.
Boxwood prefers an oceanic climate. It prefers a half schady site and can withstand temperatures down to -23Âº C(USDA zone 6). In its natural habitat is is found on neutral to calcareous, humous, stony and loamy soil. As a garden plant it is rather demanding: it needs neutral to very calcareous soil that is fertile, well-drained and not too dry. The plants tolerate a city climate; the leaves may discolour and burn on a sunny site in summer heat but the plants usually pull through without a problem.
Classification after Prof. Dr. Sieber
- flower beds (rich soil)
Their evergreen foliage as well as the tolerance of pruning and shade make the plants valuable for topiary and hedges. Suited for cottage gardens, rockeries, rooftop gardens, free-growing high hedges and for high cut hedges, as well as suited as cemetery plant, topiary plant, cut flowers, bee pasture and as plant providing shelter for birds.
Buxus sempervirens has some medicinal value but is only rarely used as a medicinal plant because its toxicity makes dosage difficult.
Maintenance and Propagation
To stay healthy box needs:
- soils with a pH of at least 6.0
- sufficient nutrients (compost/compound fertiliser)
- sufficient magnesium supply (apply magnesium sulphate if necessary)
Box hedges should be trimmed twice a year: the first trim takes place in March or April, the second from May to the beginning of September. Pruning in full sun will lead to leaf damages! Particular topiary specimens are trimmed more often. The shoots of free-growing specimens can be slightly shortened after flowering. Rejuvenation can take place in late spring if the plants are mulched and given fertiliser afterwards.
Box is usually propagated by cuttings. On the one hand because propagation by seed takes a long time and on the other because cultivars can only be propagated vegetatively. Cuttings of branches are at least 10 cm long, the two lowers thirds are defoliated and put into the ground. Take cuttings from September to March; August cuttings will build roots before winter.
Varities and Cultivars
Exaples from a standard selection:
- Buxus sempervirens var. arborescens, moderate growth rate, for medium-high hedges from 50 cm height on, very well suited for topiary
- Buxus sempervirens 'Herrenhausen', wide bushy growth with a very dense and hemispheric habit, does not flower
- Buxus sempervirens 'Blauer Heinz', slow-growing, compact, leaves larger than species and bluish green when young
- Buxus sempervirens 'Rotundifolia', rounded to conical habit, large rotund leaves, somewhat prone to damage by heavy frosts
- Buxus sempervirens 'Suffruticosa', slow-growing and compact, reaches heights of 1 m max.
All parts of Buxus sempervirens are toxic, but especially the bark and leaves. Animals are more at risk than humans. Allergic contact dermatitis has also been observed.
Please read the health issues note!
Pests and Diseases
- Fine webs on the plants indicate an infestation with red spider mites. These sap-sucking insects mainly appear under glass and can be controlled either with insecticide or biologically with parasitic mites.
- An infestation with the box tree moth (Cydalima perspectalis) shows itself in a light beige colour of the leaves. From some leaves only the leaf veins or petioles remain while some healthy green leaves remain in between. The caterpillars first feed on the leaves, subsequently on the green bark of the branches. All parts above the affected areas die, the whole plant is covered in webs. The vermin are small butterflies from East Asia that have been into Central Europe at the beginning of the 21. century. Affected plants have to be treated with a suitable insecticide as fast and rigorous as possible to avoid total loss. A way to prevent infestation is to put up pheromone traps that attract the butterflies and are filled with a suitable poison.
- If the leaves have brown spots on the margins that converge later on the plants are very likely infested with a fungus, Cylindrocladium buxicola. The fungus may cause considerable damage, especially in wet weather. The leaves will later die off and fall to the ground, whole may even wilt if the plant is strongly infested. Green shoots have black stripes. Especially B. sempervirens 'Suffruticosa' seems to be susceptible to this fungus. The only way to effectively fight it is to remove and burn the affected plants including the fallen leaves. In addition the soil should be replaced.
- Other fungal diseases may occasionally occur, especially in dense hedges or borders. The susceptibility increases with soil and foliage moisture. Prevent by giving the plants enough space and ventilation, by cutting suspicious parts and by giving copper sulphate.
- Volutella buxi: typical symptoms are dull-green leaves and a reddish to orange coat of spores on the lower surface of the affected leaves. Shoots and branches of older plants die back, the bark will show tumours and fissures that expose the wood. The fungi usually only affect individual plants.
- Fusarium buxicola: single shoots or even the whole plant turn brown and slowly dry up. This also usually affects only individual plants.
It is advised to always completely remove and burn any affected parts and replace the soil if necessary.
Man and Buxus
Box plays an important role in garden design. It was already known in ancient Greece, the Romans used low box hedges to frame garden beds. Excavation finds in Great Britain show that they introduced this manner of garden design to the areas they conquered in Central and Western Europe. Albertus Magnus documented the cultivation of box in Germany in the 13th century. Leon Battista Alberti, inspired by Pliny the Younger, wrote about box as a garden plant in his book "De re aedificatoria" in 1485.
But it was Claude Mollet, court gardener of Henry IV of France, that finally introduced Buxus as a hardy garden plant when he used it to frame beds in Versailles. It replaced the Italian cypress that did not withstand the French winters. The French nobility very soon imitated the example of the "Parterre". AndrÃ© Mollet, the son of Claude, introduced box hedges to the Netherlands where he designed the garden of Frederick Henry, Prince of Orange and his wife Amalia of Solms-Braunfels in Honselaarsdijk. Low-cut boxwood became a typical and essential element of the French and Italian Renaissance palace gardens. It became increasingly fashionable in Central Europe with wealthy bourgeois and farmers imitating the fashion that can still be seen in traditional cottage gardens.
The use of boxwood as a garden ornamental continued in the baroque era (see topiary), at the same time cultivars with variegated foliage became increasingly popular.
Use of the wood
Boxwood is popular for turnery, being hard, dense and nearly homogeneous. It is being used to date to manufacture woodwinds, violins and chess pieces. In the past the wood was used to make printing plates of xylographs, the grain-cut timber allwoing very fine details. The toughness of the wood is substantially due to the slow growth which makes box wood rare and expensive.
Catholics decorate the crosses in their homes with consecrated box branches on Palm Sunday. Box is also used for christmas decoration instead of fir branches. In the Netherlands box branches are mounted above hearths and stable doors on Easter.
In China box symbolises a long life.
- Walter Erhardt, Erich GÃ¶tz, Nils BÃ¶deker, Siegmund Seybold: Der groÃe Zander. Eugen Ulmer KG, Stuttgart 2008, ISBN 978-3-8001-5406-7. (Ger.)
- Christoper Brickell (Editor-in-chief): RHS A-Z Encyclopedia of Garden Plants. Third edition. Dorling Kindersley, London 2003, ISBN 0-7513-3738-2.