A flagship plant of French gardens, boxwood has been adorning public and private green spaces in many ways for centuries. Easy to grow and to prune, it has an evergreen foliage throughout the year, but despite all these advantages, it is subject to a terrible pest, a parameter that must be taken into account before installing it in the garden.
Find your most frequent questions about boxwood, its pruning, its planting and the boxwood borer...
- How to take care of a box tree in a pot ?
- How to fight against the boxwood borer ?
- How to plant boxwood in the ground?
- How to plant boxwood in a pot ?
- How to prune boxwood ?
- How to use boxwood in the garden ?
- Does boxwood fear frost?
- Is boxwood drought resistant ?
- Can boxwood be planted in all types of soil?
- Can boxwood be planted in pots?
- What is boxwood?
- When to plant boxwood?
- When to prune boxwood?
- What to plant instead of boxwood?
- What is the most common boxwood species grown in gardens?
- What is the ideal exposure for boxwood?
- What are the main boxwood diseases?
- What are the main boxwood pests?
How to maintain a boxwood in a pot ?
Watering must be controlled, because in a pot, the substrate dries out quickly, especially in hot and windy weather with a very sunny exposure. Water as soon as the surface of the substrate dries to 3 cm during the summer.
In winter, if it does not rain, water every 10 to 15 days.
During the summer season, add a liquid fertilizer 'Special green plants' every 15 days to the watering.
Boxwoods grow slowly, especially the dwarf varieties used for pot culture. Repot every 3 to 5 years in a larger pot. In the meantime, a simple topdressing with compost will do the trick.
Prune in May and September if you want to give it a special shape.
How to fight against the boxwood borer?
The female moth, a nocturnal butterfly, lays her eggs on the back of the leaves, they will turn into voracious caterpillars. Up to 3 generations can follow each other in one season from June to September! There are pheromone traps, to be placed as soon as the first flights and anti-insect nets but it must be admitted that the solution is not very aesthetic!
Another alternative is to spray Bacillus thuringiensis, a bacterium that causes the death of caterpillars by ingestion. The entire foliage, including the reverse side, must be sprayed to ensure the effectiveness of the treatment. To be renewed in case of rain, and every 10 days in period of attack. Constant attention is recommended, observe the foliage, if it is covered with small webs on its reverse side and you observe caterpillars, destroy them immediately by hand and treat!
Prevent the invasion of caterpillars by encouraging the installation of chickadees which are natural predators. Place nesting boxes nearby.
How to plant boxwood in the ground?
The choice of the species or variety will depend on the use of the boxwood (see 'How to use boxwood in the garden').
- Soak the root ball in a basin of water for an hour before planting to hydrate it.
- Prepare the soil by removing wild grasses and aerating it with a grelinette. Dig a hole twice the size of the root ball in all directions.
- Scratch the sides of the hole, then pour a layer of compost at the bottom, you can add mycorrhizae to make the shrub more vigorous and less sensitive to diseases and parasites.
- Add garden soil to adjust the height so that the neck of the box tree is flush with the soil surface.
- Fill in any gaps with garden soil and pack around the base.
- Form a trough around the perimeter of your box tree to retain water.
- Water copiously.
How to plant boxwood in a pot?
- Choose a pot with a hole in the bottom equivalent to twice the size of the root ball.
- Provide a drainage layer at the bottom of the pot made of clay balls or gravel so that the roots are not constantly subjected to harmful humidity.
- Mix a good commercial potting soil and compost and add a handful of ground horn powder. Meanwhile, soak the plant's root ball in room temperature water to hydrate it before planting.
- Set the plant in the center of its pot and add more mix to fill in any gaps. Do not bury the collar of the shrub, it should be flush with the surface of the soil.
- Water, then add more mix if necessary.
- Do not let water stagnate in the cup.
How to prune boxwood?
Disinfect the blades of the shears and the pruning shears with a absorbent cotton soaked in methylated spirits or by passing them through a flame in order to avoid the risk of spreading diseases.
Training pruning
Cut back the branches to 10 cm from the base to induce branching as soon as they are planted.
The following spring, keep the carpenter branches according to the desired shape (ball, square, pyramid, spiral...). Cut the other branches. Prune the retained branches by cutting 5 cm from their ends.
In the third spring, when the box tree starts to take shape, have a light hand and prune just the ends in May and September.
Maintenance pruning
Maintenance pruning of boxwood is done when the tree has taken the desired shape in order to preserve it. Remove the dead wood at the base and remove the stunted or damaged branches. Then prune the ends of the stems in May and September to maintain the desired silhouette. Always start at the bottom of the shrub and work your way up to give the shape. For a topiary shape, a template can be very useful. For hedge trimming, use a straight line to trim straight and let the shears slide along it to get an even cut. Remember to keep the base slightly thicker than the top to allow light and rainwater to penetrate your hedge.
Rejuvenation pruning
Rejuvenation pruning is done on an older tree that is beginning to thin out at the base. With a lopper, cut back the branches to 40 cm from their base. To ensure recovery, water with nettle manure diluted to 10%, then scratch a mixture of ground horn powder and dried blood at the base of the plant.
How to use boxwood in the garden?
Boxwood is an evergreen. It therefore finds a logical application in the formation of separating or limiting hedges. Buxus sempervirens can reach 6 m in height, but it grows slowly, however, it can be used for this type of employment.
Around a vegetable garden, in a parish priest's garden, on the edge of a path or a bed, it emphasizes and delimits the contours marvelously, in this case, one will choose the variety 'Suffruticosa' very compact and not exceeding 70 cm in height or 'Blauer Heinz' which presents the same characteristics. Lovers of variegated foliage will prefer 'Nana Variegata', dark green with white spots.
All of these small varieties are perfect for creating French-style beds, where the boxwood's interlacing and twisting patterns will adorn a beautiful lawn!
The larger species can be used to partition a particular area of the garden such as around a pool, a garden room or a shed.
Boxwood has its place in topiary art because it can be pruned in all directions and thus take on conical, square, pyramidal or round shapes. Large subjects can be used to create picturesque scenes in a French garden, punctuating the corners and creating perspectives.
In individual wooden pots, cut into balls, boxwood punctuates a property entrance, on a roof terrace in corten steel pots, it will be cut into squares to emphasize a very contemporary style.
Trimmed into clouds in a Japanese style garden, boxwood always makes an impact!
Does boxwood fear frost?
Boxwood is a perfectly hardy plant as it can withstand frost down to -20°C. It can therefore be planted in most regions.
Is boxwood drought resistant?
Once properly installed, boxwood is perfectly resistant to a few episodes of drought and even to heat without any problem.
Can boxwood be planted in all types of soil?
Boxwood is not very particular about the type of soil. It tolerates limestone as well as acidic, cool or dry soils, however it grows much better in balanced, drained and moist soil.
Can boxwood be planted in pots?
Yes, boxwood can be grown in a pot as long as the pot has a hole in the bottom and is large enough to promote the plant's root development. Dwarf species and varieties such as Buxus Sempervirens 'Suffruticosa' and 'Blauer Heinz' or Buxus microphylla and its multiple cultivars are particularly well suited to this type of culture.
What is boxwood?
Boxwood, from its Latin name Buxus sempervirens, is a shrub with tough green evergreen foliage belonging to the Buxaceae family. The genus Buxus includes about thirty species.
When to plant boxwood?
The best time to plant boxwood is in the fall when the soil is still warm and the rains will help the plant take root and form vigorous roots. A spring planting is of course possible, but it should be followed by regular watering in summer to ensure a good recovery.
When to prune boxwood?
There are 3 types of pruning :
- training pruning on a young tree, which is done in spring;
- maintenance pruning on an already formed tree, which is done in two stages, in May and September, to maintain a beautiful, well-structured shape;
- rejuvenation pruning, which is only done on very old trees in May.
What to plant instead of boxwood?
If in your region, boxwood is attacked by moths and fungal diseases, you might as well turn to alternative plants such as Myrsine africana in regions with a mild climate, Ilex crenata, a hardy holly that ideally replaces boxwood in all situations, the fast-growing Burkwood osmanthus, which is perfect for forming a hedge, or the hardy charcoal, which can also withstand all the situations that boxwood tolerates. Think also of the shrubby honeysuckle (Lonicera nitida) with a compact habit and evergreen foliage that resists both cold and drought, as well as the tarentine myrtle (Myrtus communis subsp. Tarentina), ideal in the Mediterranean zone.
What is the most cultivated boxwood species in gardens?
Buxus sempervirens is the most commonly cultivated species. It is native to the Mediterranean basin. This shrub with very branched branches can reach 6 meters in height. It has small, dark green, leathery and shiny leaves that do not fall off in winter.
What is the ideal exposure to plant boxwood?
Boxwood tolerates full sun as well as half-shade or even shade. This plant is not picky about exposure!
What are the main boxwood diseases?
Two virulent cryptogamic diseases (Cylindrocladium buxicola and Volutella buxi) attack boxwood. Prevention is essential, by planting only in well-drained soil, avoiding watering the foliage and spraying horsetail decoctions every ten days during the summer. Bordeaux mixture can also be sprayed in late fall and winter.
What are the main boxwood pests?
Psyllids, midges, and the dreaded boxwood borer. Cydalima perspectalis, the deadly boxwood borer is a nocturnal moth from Asia that has been proliferating since 2008 causing immense losses on plantations.
