The barberries (Berberis), also called sour thorns, are a large genus of trees and shrubs with about 500 species. They belong, just like the Mahonas and Elfflowers, to the family of the Sauerdorngewächse (Berberidaceae). The types are widespread except in Australia on every continent, most one finds in East-Asia. They grow almost exclusively in temperate and subtropical climates.
The only barberry native to the United States is the common sour thorn (Berberis vulgaris, large photo above). It is also called vinegar berry. Since it functions as the winter host of the grain rust, however, its horticultural use was prohibited for several decades and in the wild it was almost extinct.
Appearance and growth
Barberries are small to medium-high, deciduous to evergreen shrubs with small, usually elongated or egg-shaped leaves. They form very dense, often overhanging crowns and their long thin shoots are covered with more or less long, very pointed thorns. The bark of the branches and twigs is usually light grey, the wood is relatively brittle and has a striking yellowish hue. Deciduous and some wintergreen species often have a beautiful yellow to bright red autumn colour. In some cases, evergreen barberries also change colour over the winter. Their greatest benefit, however, lies in a dense foliage dress all year round – visibility and wind protection are thus guaranteed all year round.
The flowers are relatively small and yellowish and are very strongly flown by insects. The fruits are small, spherical to ovoid berries with bright red, violet or almost black outer skin. They are edible and also very popular with birds.
Location and soil
Barberries predominantly prefer sunny locations, but are still growing satisfactorily even in shady locations. The evergreen species and breeding forms should stand out from the sun to semi-shade, as their foliage can be damaged in winter by frost and strong sunlight. Barberries make hardly any demands on the soil, as long as it is permeable and not too low in humus. They cope well on all cultivated, moderately dry to moderately moist, acidic to alkaline garden soils.
As barberries are usually offered in pots, they can be planted throughout the season. With the evergreen species, however, spring and early summer are the more suitable planting times. Autumn planting is not advisable, at least in sunny locations, because otherwise there is a risk of severe leaf damage in winter. Low humus sand or clay soil should be enriched with deciduous compost when planting.
Barberries are extremely easy to care for: As a rule, they need neither fertilizer nor additional water if they have grown in well. It makes sense to cover the root area with bark mulch so that the soil remains evenly moist and the weeds are effectively suppressed – especially with the lower species it is no pleasure to remove the unwanted plants from the crowns of the thorny bushes. It is best to wear thick rubber-coated working gloves or special rose gloves when handling barberries so that you do not injure yourself at the thorns.
If you have bought small plants, you should shorten the shoots by about one third to one half when planting so that they branch out well. After this so-called plant pruning, the shrubs generally manage without further pruning. However, they can be retracted as far as required to rebuild the crowns. Barberries are extremely well tolerated by cuttings and can be relied on to sprout even from old branches.
As usual, shrubs and hedges are trimmed to the desired height and width once or twice a year using hedge trimmers.
Deciduous species such as Thunbergs barberry and boxwood-leaved barberry are often used for hedges and borders. Due to its evergreen foliage and stocky, broad growth habit, the snow berberis is also often used for greening areas or as easy-care grave planting. The higher evergreen species can also be used for cut or free-growing hedges. Because of their thorny shoots, all larger barberries are the ideal enclosure when it comes to fending off unwanted garden visitors such as stray cats. In addition, the ecological value of the shrubs is very high: they provide many insects with pollen and nectar and the higher species are often used by birds as cat-safe breeding sites. The berries are an important source of food for the feathered friends.
In public green areas, barberries are often planted as easy-care groves. Especially rich-flowering species such as the needle-leaved barberry (Berberis x stenophylla) are very attractive eye-catchers even in individual positions in beds and borders. Weaker species can easily be cultivated in tubs and will forgive you if you forget to water them.
Tip for wild berry lovers
The fruits of the common barberry (Berberis vulgaris) are edible and rich in vitamin C. However, as they taste very sour (“sour thorn”) and one should not eat the seeds, they are mainly used for jelly, multi-fruit jam or juice. In former times barberry juice similar to lemon juice was used as folk medicine for fever and was supposed to help with lung, liver and intestinal diseases. Less acidic and even seedless varieties have been selected for fruit production. We recommend the yield variety of Korean barberry ‘Rubin’ (Berberis koreana). Their edible fruits are particularly large.
Dried barberry berries can be found on markets of Persian cultures. They are often mixed into the rice as flavour carriers. Important: fruits of other species are considered slightly toxic. A toxic alkaloid is also found in the bark and root bark of all barberries.
Important species and varieties
There are around 15 barberry species and hybrids that are of greater importance in horticultural terms. Among the most popular are the boxwood-leaved barberry (Berberis buxifolia ‘Nana’) as well as several evergreen representatives such as Berberis julianae, Berberis x frikartii and the snow barberry (Berberis candidula).
Also very popular with gardeners are the Thunbergs Berberitzen (Berberis thunbergii), also called Hecken-Berberitzen, which also offer the greatest variety. In the bed their flat spherical dwarf forms are a real discovery. Try out how a refreshing light yellow ‘Aurea’ sets accents or a dark foliage selection like ‘Bagatelle’ acts as a haven of peace. The structural encoders can be used as margin stops just as well as in individual positions. In the case of an ‘Atropurpurea Nana’, four to five plants per metre are expected. When it comes to higher hedges, the big blood berberite ‘Atropurpurea’ is often used.
Like all Thunbergii forms, it is easy to cut into shape and provides variety with fruit decorations and autumn colouring. Blood barberries intensify the luminosity of their reddish-purple leaves towards winter. Flaming tones can be found in green and yellow-leaved representatives.
Barberries can be reproduced relatively easily. In the nursery this is usually done by slightly woody cuttings in early summer. Stronger growing deciduous species like for example the Ottawa berberis (Berberis x ottawensis) can also be grown well from wood. The cultivation from seeds is basically also possible with the wild species, but not interesting for hobby gardeners as a rule.
Diseases and pests
Especially the evergreen barberries are hardly affected by diseases. With them, however, Dickmaulrüssler-Food occurs more frequently. Deciduous barberries often suffer from powdery mildew.