The evergreen boxwood (Buxus sempervirens) has a long tradition in horticulture and can be found in many palace gardens and around manor houses. Geometric shapes such as spheres, but also pyramids or cones, bring a calm atmosphere to the garden. The human eye perceives symmetry as relaxing, which is one of the reasons why formal gardens with strictly trimmed box trees are inviting, elegant and well-kept in every season. The box tree is relatively easy to care for, but only develops its compact growth when it is pruned regularly. The first shape cut is especially important and determines the later appearance of the plant. Cutting a ball is not that easy. There are some tricks, however, such as an even,
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Which varieties are suitable for the spherical shape?
Not every box is equally suitable for the spherical shape. There are clear differences in terms of size, vigor, leaf shape and leaf color. When buying, the natural growth of the boxwood should always be taken into account and match the desired cut shape. Bushy growth forms are particularly suitable for spheres. Before deciding on a variety, you should consider how the ball will look later in the garden and what size it should be.
Weak-growing varieties are suitable for small figures, and those that are also used for edging paths or beds. The varieties “Suffruticosa”, the relatively frost-hardy “Blue Heinz” and “Green Gem” should be mentioned. These slow-growing varieties achieve growth of up to 5 cm per year and are therefore particularly suitable for smaller balls.
If the balls are to be nice and large or the box is to be cut into more complex figures, a strongly growing variety must be selected. The varieties “Handsworthiensis” and “Rotundifolia” are ideal here. These varieties grow a good 10-15 cm per year, so that a considerable spherical shape can be realized more quickly.
Other varieties that are used as a hedge are not necessarily suitable for the noble spherical shape. Before purchasing variegated varieties such as “Elegantissima”, you should also consider that these varieties are more sensitive to frost and that they always need a warm parking space in winter.
Time for the topiary
There are some easy to remember rules for pruning boxwood. It is always cut on cloudy days to avoid sun damage to the fresh cut. Basically, the boxwood can often be cut. In fact, the more often, the better. A four-week break should be observed in the cutting rhythm, so that the book can drive out again. Frequent cutting helps to achieve a dense and compact growth, a prerequisite for box trees that are to be cut into geometric shapes such as spheres, cubes, cones or the like.
Another rule is that the book is best cut in the months without an “R”. The cutting season is between May and August. Two cuts a year have proven to be a good rule of thumb so that the boxwood stays healthy and maintains its beautiful shape for a long time. Based on the main growing season between April and September, the best pruning dates are mid-May and mid-August.
The first cut from mid-May to mid-June at the latest is the topiary. He brings the plant into shape and trims the box around almost the entire annual shoot, recognizable by the light color of the leaves. The plant can grow again over the summer, but should then be trimmed again in mid-August to maintain its shape. The second cut is also called a care cut. After the cut in August, the box tree has another time to prepare for winter. If you cut too late in autumn, there is a risk of frost damage to the plant. Outside of the main growing season, no pruning is necessary, as the boxwood hardly grows at all.
The right tools
Since the boxwood has a dense growth and particularly hard wood, which is popular for turning, there is no getting around good tools. In any case, the tool used should be kept clean and sharp so that the shoots can be easily cut and there is no slipping. The following scissors are available:
- The all-purpose pruning shears with a long cutting edge will help ensure that the branches are cut properly and not crushed. If box is used extensively in the garden, a lot of bushes can be trimmed relatively quickly with the all-purpose scissors. However, you need strength in your arms here, especially if the cutting takes longer.
- Special boxwood shears are particularly suitable for simple shapes and small boxwood specimens, as they have a short cutting edge.
- Sheep shears are traditionally used to cut the box, which are forged to a high quality and hardly need to be sharpened. The sheep shears, originally from Great Britain, are only suitable for fresh shoots that are not yet hardened or lignified. It can also be used to work out more complex shapes and figures. The sharp cut of the sheep shears also creates smooth contours. However, sheep shears have the disadvantage that they put a noticeable strain on the wrist after a while. Therefore, this cutting tool is more suitable for smaller specimens or for fine-tuning.
- The cordless shears are convenient and work quickly. Due to the higher acquisition costs, however, it is only worthwhile if there is a good stock of box trees in the garden. In addition to saving time, the advantages are also energy savings. However, this can be at the expense of the plant. Due to the vibrating movement of the cordless shears, the leaves quickly fray and then turn yellowish-brown. In addition, the cordless shears are more difficult to control and it is easy to cut off too much. Boxwood does not tolerate such radical cuts. Motorized gravity should therefore be practiced and handled carefully.
Cutting technique for the round box ball
The annual shoots are cut, i.e. all new branches with light green leaves. If the sphere is to grow in size, a few millimeters of these bright leaves can remain. If only the shape is to be preserved with the cut, you can cut down to the dark green leaves.
Be careful not to cut too deep into the boxwood. No brown spots should be visible after the cut. The box can usually no longer sprout from the woody, brown shoots. If you cut too deeply, unsightly holes can arise that will only regenerate slowly. If the entire plant is pruned too radically, the box can even die. Therefore it is important to approach the final shape with careful cuts.
The cut is always started from the bottom up, so that all cut branches fall to the ground and do not hinder further cutting. As a rule, however, there is still some leaves left on the book, so that you can regularly slide your hand over the contours to remove unwanted leaves.
Box trees can be brought into spherical shape with a little free hand practice. If you are unsure, you can use a template. They are either available from specialist retailers or in a self-made version. The right cutting technique then helps to achieve the perfect, spherical result.
The cutting technique for a perfect ball requires a smooth cut that gently removes layer by layer. Beginners in particular should not cut too generously into the wood, as this can easily create unsightly holes. It is better to approach the spherical shape with caution. To do this, it helps to imagine the boxwood as a kind of globe, which is divided by an equator in the middle and four vertical lines of longitude. In the first step, the paths for the equator and the longitudes are cut into the sphere. If all these tracks are even, all that remains is to bring the areas between the tracks to the same length.
Using a stencil
The specialist trade offers different templates. One variant is wire frames that can be bought as spheres or animal shapes. These remain around the boxwood for a long time, so that the topiary can be cut along them. These shaped wire frames may still be visible for a certain period of time until the boxwood has properly filled the shape. The advantage of these shaped wire frames is the precise shape retention, in fact, you can’t cut too much without hitting the wire with the scissors. Cutting complex shapes, such as animal shapes, becomes a simple exercise. Whether such a purchase is worthwhile for a spherical shape must be assessed on a case-by-case basis.
There are also stencils in the shape of a semicircle made of metal. At the time of the cut, these are held against the boxwood with one hand to ensure a better cut. The advantage of these stencils is that they do not have to remain around the plant for months and, due to their mobility, can be used for several box trees. The template is then placed on the boxwood until a perfect and even spherical shape is achieved.
It is relatively easy to make your own cardboard stencil. For this purpose, the diameter of the existing boxwood should first be measured, this serves as a guideline. Folding rule, tape measure or a piece of string can be used for this. To draw the semicircle template, a pen is attached to a cord that is only half the length of the diameter you just measured. One end of the cord is fixed to the edge of the cardboard with the index finger and thumb, the end of the cord including the pin is then drawn in a radius around the fixed point. This creates an even semicircle. The painted semicircle only needs to be cut out and, like the metal template described above, is ready for use. This simple, self-made template helps to achieve a uniform spherical shape, just like the metal templates from specialist shops.
Care instructions for the spherical boxwood
The more often the box is cut, the more compact and full the growth will be. This also goes hand in hand with an increased need for water and nutrients. If almost all annual shoots are regularly pruned, it encourages the plant to sprout again. Therefore, it is important to ensure regular watering and fertilization so that the box tree can quickly replace its missing leaves. The boxwood benefits from compost, horn meal and other organic fertilizers.
The strict pruning doesn’t seem easy at first glance, but there is hardly a simpler plant for topiary than boxwood. With a few tricks and only two cuts per year, the book can be kept in shape and the garden can be upgraded. The spherical shape in particular gives the garden an elegant and well-groomed appearance all year round.