The Berberidaceae family is becoming more and more known and appreciated by Quebec gardeners, mainly the Thunberg (Berberis thunbergii) barberry, also called Japanese barberry or simply barberry. It must be said that we were unable, for 35 years, to cultivate and appreciate the decorative beauty of the barberry in Quebec, after these shrubs were forbidden to grow because certain species were the hosts of an extremely virulent fungal disease, black rust (Puccinia graminis).
Thunberg barberries generally form very branched and compact shrubs. Their height varies between 1 and 2 m (3 to 6 ft.). The bell-shaped flowers are usually yellow or pale yellow and are followed by red berries. The branches are very thorny.
Here are some varieties to prioritize, they come from selections or breeding methods making them resistant to black rust. They are sold in almost all garden centers in Quebec:
Japanese barberry atropurpurea – Berberis thunbergii
Prior to the removal of barberries by the Canadian government in 1966, the Japanese barberry atropurpurea was used extensively in many Quebec cities to create decorative hedges around opulent residences because of its compact vegetation. These living fences were even defensive, this shrub’s thorns being fearsome, even for cats.
This variation of the Japanese barberry’s small oval leaves shows a more or less dark purple color in the spring, which tends to become green during the summer. In the fall, this rounded shrub’s leaves turn purple-red. Its flowering occurs in the spring and is composed of small bell-shaped yellow flowers that contrast well with that period’s flaming foliage. The flowers appear under the foliage.
The Japanese barberry atropurpurea is typically 1 m (3 ft.) high and 80 cm (32 in.) wide. This shrub is grown in well-drained soil, in the sun or partial shade. In a shady situation, its colors are usually less bright. As it is hardy until zone 3, this star plant can be grown in many regions of Quebec.
‘Concord’ Japanese Barberry
Berberis thunbergii var. atropurpurea ‘Concord’
This Japanese barberry cultivar has a velvety purple-red foliage that usually only reaches 18 inches (45 cm) tall. In a favorable environment, it can still reach 50 to 60 cm (20 to 24 inches) high and 50 cm (20 inches) wide. ‘Concord’ forms a shrub with dwarf, compact foliage. In the spring, it gives yellowish flowers which are followed in autumn by bright red ellipsoid fruits.
‘Crimson Pigmy’ or ‘Atropurpurea Nana’ Japanese Barberry
Berberis thunbergii var. atropurpurea ‘Crimson Pigmy’ or ‘Atropurpurea Nana’
Obtained in Holland following the selection of a plant in a batch of purple-leafed Japanese barberry, this shrub is smaller than the atropurpurea variation. This cultivar was introduced to the horticultural market in 1942. This small dwarf bark is only 60 cm (2 ft.) high and only 90 cm (3 ft.) wide. Its foliage is purple-red in the summer and red in the fall.
‘Rose Glow’ or ‘Rosy Glow’ Japanese Barberry
Berberis thunbergii var. atropurpurea ‘Rose Glow’ or ‘Rosy Glow’
The new foliage of this barberry, also known as ‘Rosy Glow’, is pink spotted with deep pink and variegated with cream. As they age, the leaves become brown and its variegation is less pronounced. This shrub, introduced in 1957 by a Dutch nursery, is vigorous, up to 1.5 m (5 ft.) high and 1.2 m (4 ft.) spreading.
The ‘Rose Glow’ Japanese barberry has erect stems that form a very dense shrub. Its foliage gives the most beautiful colors in the sun. In the fall, the colors of its leaves become more vivid. Its spring flowering is yellow and is followed by ovoid pink-red berries. The leaves take on an orange- red to purple-red fall hue.
We can prune this barberry so that it keeps its shape and beautiful coloration of its young shoots.
‘Aurea’ Japanese Barberry
Berberis thunbergii ‘Aurea’
This barberry is a star plant in landscapes, because of the brightness of its small golden yellow leaves. If this shrub is planted in the shade, its leaves turn yellow-green. It retains its color better in the sun.
Be careful, even if it is slow-growing, the ‘Aurea’ Japanese barberry can reach 1 to 1, 2 m (3 to 4 ft.) high and sometimes 1.5 m (5 ft.) wide. If you prefer a smaller plant, you should choose the ‘Aurea Nana’ cultivar, which is only 60 to 90 cm (2 to 3 ft.) High.
In the spring, this barberry produces pale yellow flowers along the stems: these are not very decorative. This cultivar gives red berries in the fall. Its fall colors are multiple, the coloring of the leaves vary between orange, red and yellow.