Planting buxus: tips for growing, fertilising & care
Hardly any other evergreen plant is as popular as the box tree. This is our guide to box tree care, diseases, pests and varieties.
Box trees (Buxus) hold a special place in the hearts of many gardeners and garden enthusiasts. They have become inseparable from garden landscapes. These evergreen plants decorate gardens and parks as hedging or screening plants, or sometimes (because they can be pruned and formed easily) in the shapes of various animals. However, there are a few tips to follow so that your box tree can thrive splendidly. Here you can learn everything from planting and care to propagation and overwintering of the evergreen shrub.
Box tree: origin and characteristics
The name of the box tree comes from the Latin term ‘buxus’ and from the Ancient Greek word ‘púxos’. Even in Ancient Greece, many objects were made from the wood of the box trees. The box tree family (Buxaceae) consists of 70 species worldwide.
The box tree occurs more often as a shrub or a hedge, but can also grow as a tree. The leaves are evergreen, dark green and leathery. The box tree makes little demands on its location and is otherwise very easy to maintain too. It also copes very well with frequent cutting. However, the evergreen bush grows very slowly, only 10 to 20 centimetres in a year.
Buying box trees
When buying your box tree, you should make sure that the plant makes a healthy, well-groomed impression. Look out for any signs of disease or pests on the box tree. In addition, the foliage should be rich and green. The roots should also be checked.
Box trees can be bought in garden centres, hardware stores or tree nurseries. Many online retailers also offer box trees that can be shipped and delivered right to your door.
Box tree species and varieties
These two types of boxwood (Buxus) in particular are much adored by many gardeners: Buxus sempervirens and Buxus microphylla. Buxus sempervirens is the common box tree and native to the Mediterranean region. Buxus microphylla, the Japanese or small leaf box tree, originates from Korea and has been cultivated in Japan for centuries. In the following, we introduce you to popular varieties of these two species.
- ‘Suffruticosa’: The variety best suited for bordering flower beds and as a hedge. It forms long, medium sized, light green leaves and is usually not taller than 50 cm.
- ‘Blauer Heinz’: This variety is also suitable for bedding as it is low-growing and frost-hardy. The leaves have a slight blue hue to them.
- ‘Aurea Pendula’: This boxwood variety is interesting because of its special leaf colouring. After sprouting, the leaves are golden yellow and later turn green.
- ‘Globosa’: If you want a box tree shaped like a ball, you should choose this variety; it grows slightly rounded naturally.
- ‘Faulkner’: A popular variety of the Buxus mircophylla. It has shiny olive leaves and is very resistant to drought and cold. Faulkner bush trees grow very bushy and are therefore well suited as ground covers.
- ‘Herrenhausen’: Another favourite boxwood variety. This variety is particularly suitable as a hedge or a bed border and it is rather small and resistant to fungal infestations.
Planting box trees: location and instructions
The box tree can be content in many locations, but to create ideal conditions for growth you should consider a few things. The ideal location for your box tree should be sunny and warm. The box tree particularly likes locations with morning and evening sun. The full midday sun, on the other hand, is not its favourite. The soil should be loose and airy. Avoid waterlogging by working sand into soils that are too heavy. Slightly damp, alkaline soils with a pH value between 6.5 and 7.5 offer ideal conditions for box tree growth.
The best location for planting a box tree:
- Sunny to semi-shady location
- Loose and airy soil
- Soil rich in humus
- pH value between 6.5 and 7.5
The optimal time for planting the box tree is in spring between March and May. To plant the shrub, dig a sufficiently large planting hole. Now place the box tree in the middle of the hole, then fill up the hole with the excavated soil, preferably enriched with compost and water it well. When planting the buxus as a hedge, make a ditch and plant the box trees with a distance of 20 centimetres for low hedges and 30 to 35 centimetres for taller hedges.
A step by step guide to planting a box tree:
- Dig out a hole for planting
- Place the box tree in the middle of the planting hole
- Fill it with excavated soil and compost
- Water the plant
Re-planting box trees
You can also transplant box trees when they are very old. Choose a day that is frost-free but not too hot. To dig out the box tree, use a spade to dig out the root ball (in a circle as wide as the crown of the box tree). The depth depends on the size of the tree – at least 40 centimetres for a small bush and at least 60 centimetres for a large bush. Use a digging fork to loosen the ground under the bush as much as possible. Then lift out the box tree and cut back any damaged roots. Afterwards, the excavated box tree should be left to sit in some water in an empty pot for half an hour. It can then be planted at its new location or in a flower pot, as described above.
Reproducing box trees
Two vegetative methods are suitable for the propagation of box trees: propagation by cuttings or by division. We will introduce you to both in the following.
Propagating box trees with cuttings
The best time for propagation by cuttings is late summer or autumn. Strong, bushy plants, from which older, branched shoots can be used, are most suitable, but young plant can also be used for cuttings. One-year-old shoots of the buxus are the best candidates for this method.
- Tear off biennial shoots about 15 centimetres long against the direction of growth (with a movement downwards)
- Shorten shoot tips by a third
- Remove leaves from the lower third of the newly cut off branch
- Cut off protruding bark
- Plant in pots with cuttings up to the leaf base
- Water thoroughly and keep watering to maintain moisture
- Let the cuttings grow in room temperatures
- Plant outside the next year
Dividing box trees
In this method, a box tree is cut through and divided into two parts. However, this method is not without risk and it is possible that the divided tree will contract diseases or pests through the vulnerable openings. This method is clearly inferior to the easier way of multiplying box trees by cuttings.
- Dig out the plant generously around the root ball (with a radius at least the current height of the tree)
- Split the tree on a hard surface with a spade or saw
- Newly created plant should have at least two shoots
- Plant outdoors or in a pot
Maintaining box trees
Although the box tree is generally very easy to care for, it needs to be watered and fertilised sufficiently. Continue reading to find out about the proper watering and fertilising care as well as pruning and overwintering.
Watering box trees
Since the box tree has only shallow roots, it cannot draw water from deeper layers of soil. Therefore, it is dependent on regular watering during dry periods. With potted plants, you should take special care to ensure that the soil does not dry out – even in winter. If you find brownish leaves and shoots on the plant after winter, this can be a sign of drought in the cold season. In hot and dry summers, the box tree should be sprayed with a hose or watering can to remove dust from the leaves.
Fertilising box trees
Typical symptoms that your box tree suffers from nitrogen deficiency are reduced growth and yellowish discoloration of the leaves. To prevent this from happening, however, the box tree is dependent on regular fertilisation. The best time to fertilise is from spring to early summer. Later in the year, it is not recommended to fertilise, as shoots promoted by the fertiliser die off quickly during frost. For box trees, we recommend fertilising with a fertiliser that offers a long-term organic effect – such as compost or organic fertilisers. An organic slow-release fertiliser provides the plants with nutrients over the long term and at the same time promotes healthy soil life and production of hummus.
Pruning box trees
Pruning plays an important role in the box tree care: it promotes growth, the bushes become denser and more lush. Moreover, by cutting the box tree can be shaped. It can be pruned between April and September. Importantly, on the day of pruning the weather should be mild – not too sunny and without rain. Both hand scissors and electric scissors are suitable for pruning, but they should be sharp. To achieve the desired shape of the box tree, stencils can also help.
Overwintering box trees
The box trees usually manage the winter in the garden beds or as hedges alright. However, the box trees in pots are more sensitive to the elements and therefore some measures need to be taken in order for the box tree not to freeze to death. If the pot with the box tree is not too heavy, you can simply move it into a protected place for the winter (for example next to a house wall). It is also important to protect the pot and the box tree in it from below, so placing a wooden plank underneath it is a good idea. If the pot is too large or too heavy to be moved, you can protect the plant by using jute bags. On particularly cold days and nights, the box tree itself can be wrapped in the jute bag ‘blanket’. Also remember to water your box tree regularly in winter – but only on frost-free days to avoid frost damage to the roots.
Box tree diseases
There are several diseases that can have a negative impact on the box tree and some of them, unfortunately, can lead to severe implications. Here we give you a short overview of the most important box tree diseases.
The Volutella buxi fungus penetrates into the plant through its bark, which can cause the shoots of the buxus to die. If your box tree is affected by Volutella buxi, you should cut back and remove the diseased parts.
Boxwood blight or boxwood leafdrop
Triggered by the fungus Cylindrocladium buxicola, the boxwood leafdrop, as the name suggests, causes entire box trees to lose their leaves and then to atrophy. The first signs of infestation are brownish or orange spots on the leaves, which expand as the disease progresses. Finally, the bush discards all its leaves and the shoots become bare. With severe infestations, the only thing that helps is to remove the affected plants; alternatively, a fungicide can help.
You can read here how you can recognise Volutella blight and what can be done about it. You can also find a more detailed description of the boxwood blight here.
Another disease caused by fungi is boxwood rust. Rust fungi usually stain the leaves of the plant from rust red to brown. The affected parts of the plant can simply be cut off and disposed of.
We have prepared detailed instructions for you on how to detect and combat box tree diseases.
Box tree pests
The most infamous pest of the buxus is definitely the box tree moth. However, there are also other organisms that like to munch on the evergreen shrub. This is our brief overview of the most common box tree pests.
A comprehensive overview of boxwood pests and how to control them can be found here.
Box tree moth
The box tree moth (Cydalima perspectalis) is a newly introduced pest in Europe that has been causing a significant amount of damage to European box trees in the recent years. This species becomes active from the middle of May and until September the caterpillars of the box moth can completely defoliate the evergreen shrubs. Here you can learn everything about the box tree moth.
This article discusses how to get rid of the box tree moth with household remedies. If you are looking for other tips and tricks to eliminate the box tree moth, click here.
Twisted shoots and leaves are caused by mites. Although white mites do not harm the box tree, the appearance of the buxus suffers. If you discover infested parts of the plant, prune them away and remove them to stop the spreading of the mites.
The boxwood psyllid also preys on the buxus foliage. You can recognize the infestation by the spoon-shaped curved leaves. To get rid of the infestation it is best to cut back the affected leaves.
Box tree: is it toxic to humans and animals?
It is safe for the box tree moths and other box pests to feed on the buxus. For everyone else, however, the evergreen bush is highly poisonous. This is due to the 70 different alkaloids in the roots and leaves of the plant. But since these taste very bitter it is very unlikely that anybody would eat them in large quantities. However, you should be careful with children, because even a small amount of the poison can lead to terrible consequences for those with a low body mass. Therefore, supervise small children in the garden and teach them not to eat the plant at an early age. In addition, be very careful with pets (especially rodents) around the box tree. If you take these precautions, you can grow the evergreen bush without worries.
More detailed information about the harmfulness of the box tree can be found here.
But maybe it doesn’t always have to be a box tree? You can find out about possible alternatives to box tree here.