Boxwood borer - where does the pest come from?

Until a few years ago, boxwoods were considered relatively free of pests. There were one or two fungi that spoiled the mood of hobby gardeners, but on the whole, box trees in this country proved to be easy to care for and relatively robust. This changed in 2006, however, when the boxwood borer (Cydalima perspectalis), which originates from East Asia, arrived in Europe and Germany, presumably as an illegal passenger on a container ship carrying plants. Shortly afterwards, the first damage to the boxwoods was


and in the meantime box trees in large parts of Europe have been infested by the pest. In the following, we present all relevant information about the boxwood borer and its control. Although this is time-consuming, it can be crowned with success if timed correctly. Furthermore, we will show you how you can easily save yourself all the trouble with the box tree borer by simply choosing a Bloombux® as an excellent and box tree borer-free alternative to a classic box tree.

Buchsbaum Zünsler

What is a boxwood borer?

The boxwood borer is a so-called small butterfly, which is originally native to East Asian countries such as Japan, China or Korea. The boxwood borer was probably brought to Germany by container ships loaded with plants. This is supported by the fact that the first reports of infestation appeared mainly in areas with inland shipping and container traffic. The box elder is classified as an invasive species, which means that this alien species can have a major negative impact on local biodiversity.

This is mainly due to the fact that the boxwood borer feeds exclusively on various plant parts of the boxwood and there are few natural enemies. In the meantime, many stands with numerous box trees have already been destroyed by the voracious pest within Germany. In some cemeteries there is even a ban on box trees. This is precisely why our Bloombux® is recommended as a real alternative: it has many of the typical and extremely popular characteristics of boxwood, but in fact it is a rhododendron. As such, it not only scores additional points with an attractive bloom, but also proves to be insensitive to the boxwood borer.


Buchsbaum Schädlinge
Buchsbaum Zünsler Falter

Boxwood borer moths, caterpillars and eggs: How do you recognise a boxwood borer?

The caterpillars of the boxwood borer are particularly dangerous for boxwood. The moth itself is usually not found on the boxwood, but only lays its eggs there. The small butterfly lives for about eight days and develops from the voracious caterpillars of the pest. With a wingspan of a maximum of 4.5 centimetres, the boxwood borer moth is relatively small and is also easily overlooked due to its visually inconspicuous nature. The box elder moth has brightly coloured wings, which are framed by a brown border. Within the brown border there is a bulge with a white spot. This is regarded as an unmistakable sign by which the box elder moth can be recognised. Since the moth is nocturnal, it is hardly ever seen.


In contrast, the caterpillars of the boxwood borer are visually much more conspicuous: they are up to five centimetres long and are characterised by a yellow-green to dark-green colouring. They also have black and white longitudinal stripes and conspicuous black spots. The caterpillars of the box elder have white bristles and a black head capsule. Anyone who discovers one of these caterpillars on their box trees or finds the small butterflies in their garden can assume an infestation. Since box borers reproduce relatively quickly and, depending on the temperatures in our region, can produce up to two generations per year, it is necessary to act quickly. To help you recognise an infestation of boxwood borers even more quickly, we have summarised the visual characteristics of the moth and caterpillar here:


Zünsler Raupe
Buchsbaum Krankheiten
Buchsbaum Zünsler
Zünsler Falter

Life cycle of the boxwood borer: When does the borer come back?

The life cycle of the boxwood borer can cover a period of up to three months in the summer generation, it begins with egg laying. The boxwood borer moths lay their eggs on the underside of the boxwood leaves. The eggs are inconspicuous and hardly visible. The eggs are laid mainly on the outer leaves of the boxwood.

The last generation of the boxwood borer lays its eggs before the onset of winter. The caterpillars that hatch from the eggs then spin themselves into a cocoon between the leaves of the boxwood to overwinter. From mid-March, the caterpillars begin to eat the soft tissue of the underside of the leaves from the inside. This initially results in typical "window feeding", because the upper tissue of the leaf - the epidermis - remains.

As soon as the caterpillars of the box elder reach the end of their development cycle, they pupate and grow into a moth within about seven days. This in turn has a life expectancy of about eight days and during this time lays the eggs for the following generation. The adult stage of the boxwood borer, the moth, is able to lay up to 150 eggs, which in turn develop into new voracious caterpillars.

Our Bloombux® does not provide a habitat for the box tree borer because it only has the growth characteristics of a box tree, but is actually a rhododendron. Accordingly, the otherwise very resistant caterpillars of the boxwood borer do not find any food supply in Bloombux®, so there is no danger of infestation.

Wie ist das Aussehen und kann sich Buchsbaum erholen?

Anyone who has to deal with an infestation of box elder borer will be able to see the consequences after a very short time. Anything from minor feeding damage to the complete death of the plant is possible. In general, the longer a boxwood tree is inhabited by a population of box borers, the greater the damage. As long as the plant provides a sufficiently large food supply for the pests, they will not look for a new host. Initially, the caterpillars of the boxwood borer feed mainly on the lower parts of the plant. The focus of interest is on the leaves, before the pests then turn their attention to the bark of the twigs.

Buchsbaum Laub Krankheit
Blatt Krankheit

Parts of the plant lying above the feeding site often die off and at the latest then an infestation becomes obvious. Leaf skeletons and petioles are usually spared by the caterpillars, sometimes even yellowish remains of the leaf tissue can remain on the plant. In addition, the caterpillar of the box elder has the ability to weave threads, which it uses particularly eagerly, for example to glue leaves together, to weave itself in or to move from one leaf to the next. Over time, the infested boxwood is therefore often surrounded by a veritable web. If the pests are not controlled in time, there is a risk that the plant will die. Plant lovers, on the other hand, have less trouble with our Bloombux®, which does not provide any habitat for the voracious box elder borer and therefore survives the summer without damage.


Was hilft gegen Buchsbaumzünsler?

Als u de dood van uw buxus niet wilt accepteren, maar de buxusboorderinvasie die over Europa rolt actief wilt bestrijden, moet u zo vroeg mogelijk beginnen met de bestrijding van de buxusboorder. Hoe eerder de verspreiding van plagen wordt tegengegaan, hoe moeilijker het voor hen zal zijn om te overleven of geschikte habitats te vinden. Het is bijzonder ongecompliceerd om onze Bloombux® te gebruiken in plaats van een buxus. Dit is immers absoluut ongevoelig voor de vlierboorder en levert geen habitat op. Op die manier beschermt u zich niet alleen tegen een onaangename plaag, maar maakt u tegelijkertijd de leefomstandigheden voor de onbeminde boorder moeilijker.

Er zijn verschillende manieren en middelen om de buxusboorder te bestrijden. Als u een besmetting in een vroeg stadium ontdekt, kunt u de rupsen eerst met de hand van de plant verzamelen en ze vervolgens weggooien.



Buchsbaum Hecke Schädling
Buchsbaum Zünsler

If you are looking for a remedy against the boxwood borer, you will soon find that they are few and far between.  In East Asia, the original distribution area of the beetle, neem oil is often used to combat the pest. There is no reliable knowledge as to whether this pesticide is also helpful in cases of heavy infestation.

Insecticides are the first choice for many owners of infested boxwoods when it comes to controlling the boxwood borer. A plant protection product against the boxwood borer should preferably be used at the beginning of the life cycle, when the caterpillars have already hatched from their eggs but are still small. It is important that the agent against boxwood borers is applied evenly with sufficient pressure and that all leaves are evenly wetted. Most plant protection products act as a feeding poison. Biological control of the caterpillars is also possible. It should be borne in mind that other insects can also be affected when using plant protection products against the box elder moth. Bees in particular can be harmed when insecticides are applied. Especially in view of the bee mortality and the possible consequences for our ecosystem, it is advisable to use such agents only in extreme emergencies.


INFO: Our Bloombux® is insensitive to the boxwood borer and accordingly does not need to be treated with insecticides that are dangerous for bees. Especially during the flowering period, Bloombux® attracts numerous bumblebees and therefore proves to be an asset to our gardens.


Living with the box borer?

The East Asian boxwood borer has spread continuously since its introduction to Europe in recent years. Unfortunately, for this reason, it is not currently expected that this development will change in the near future. In fact, experts predict that the damage to the popular boxwood species in this country will probably increase in the coming period. Anyone who has already planted boxwood in their garden must take consistent action against the pest. It is important to control the boxwood borer at an early stage to avoid shoot death or complete death of the affected plants. Unfortunately, however, the boxwood borers prove to be relatively robust and the remedies against boxwood borers are few and far between. The use of chemicals is often only advisable as a last resort because of the intolerance of bees. In case of doubt, an expert from the responsible plant protection office should be consulted. However, even if an effective plant protection product is used against boxwood borers, it is difficult to kill all the borers. Even if this is successful, a new infestation at a later date cannot be ruled out.


Bloombux® und Bloombux® Magenta als Kugel

Conclusion: Buy a resistant boxwood alternative - with Bloombux® you will never have to deal with the borer again.

If you love boxwood and would like to purchase suitable specimens for your own garden or for larger garden areas, you should consider using Bloombux® instead of a boxwood. This is a special cross between two rhododendrons that has proven to be resistant to the boxwood borer as well as many other pests and typical boxwood diseases. In addition, the Bloombux® has an attractive flowering season from May to early June. As an easy-care and evergreen hedge, area or container plant, the Bloombux® also presents itself with the best characteristics of the box tree and can become a highlight in any garden and park landscape with a topiary, for example.