There box hedge it is one of the symbols of the Italian topiary tradition whose splendor is still clearly visible since this plant (before hedging the box is a plant) also lives 600-700 years from what we know, and perhaps even more.
For some years, however, the boxwood (buxus sempervirens) is threatened by a caterpillar of Asian origin, the cydalima perspectalis, aka box borer, aka defoliator caterpillar, which can burn a hedge within a few weeks amen and thanks.
This is why it is useful to put together everything we know about boxwood, from fertilization to pruning, from chemical to climatic affinities, to help us keep this essence as good as possible.
For the cure from the borer attacks of the boxwood, a real emergency in Italy since 2011 (I know something firsthand!) Read the articles that you find linked at the bottom of this.
Pruning the box hedge
Being an ornamental plant, perhaps the most ornamental of all for how it can be shaped, we could only start with pruning. The boxwood it has a slow growth and in this it must be respected. Having said that, the small leaf authorizes the use of the hedge trimmer which is very useful for 'external' aesthetic modeling.
However, if you need to 'cut' the branches as well as shave the last few throws, it is good to use shears (always sharp), remembering that there are also specific hedge shears. The boxwood it has a very hard wood (also valuable and usable for the construction of various objects) and if let go it reaches 5-6 meters in height. In a boxwood of these dimensions the hedge trimmer is not needed, if anything, the trimmer.
The boxwood it blooms in March-April depending on the climate (the small flowers are yellowish and very fragrant) and should be pruned at the end of June to keep it in height and health. During the summer, 1-2 other shaping prunings can also be done, the last one not later than the end of September or early October.
If you use the hedge trimmer remember the technique valid for all hedges: always proceed in the same direction and work first on the sides and then on the top. If you use shears and need to reduce the height, proceed little by little, stopping and moving away frequently to assess the overall situation and avoid excessive stripping.
Remember that even the boxwood like the other hedges (with the exception of the yew) it does not throw back at the base and this is the part that risks remaining bare. If the hedge is linear it is useful to keep the upper part narrower, giving a pie shape.
If you want to give the box hedge a particular shape, the best system is to use a shaped wire model: place it on the bush and cut the protruding branches. However, be patient because it takes time to see a good result.
After cutting, clean the hedge well both at the base and in the tangle of the branches. Possibly also use a jet of water or water to remove from boxwood dust residues, especially if the period is dry. If the cut has been consistent, a light fertilizer will help the hedge overcome stress.
For a hedge in the ground, fertilization may not be necessary, but it is useful for shrubs in pots and on hedges where you want to improve the brightness of the green. Horse manure is used in early spring, or a slow-release organic fertilizer in granules three times a year. The soil is fertilized, not the leaves.
Ideal soil and conditions for boxwood
The boxwood it is a plant in its own way rustic (which does not detract from its elegance) which adapts well to different cultivation environments at different temperatures, however it prefers fertile, humid and well-drained soils. Better if the ground is also a little calcareous, otherwise you can add limestone from time to time.
The boxwood it looks good in the sun but also grows in the shade, the ideal location is in a semi-oblique position. It does not fear the cold, even when the temperature goes below zero, and the roots should be protected from frost only when the plant is in a pot. In summer, no special watering is required, but if the soil is kept a little moist it is better. In winter, rain is enough.
Put these attentions and yours into practice box hedge it will grow strong and bright for centuries. In the event of a borer attack, read here:
- Topiary art: technique and nurseries
- Boxwood defoliator caterpillar: my story
- Bacillus Thuringiensis for lepidoptera and boxwood caterpillar
- Biological control of the box borer