There are seventy species of mahonia in all. Their name honours Bernard McMahon (1775-1816), an Irish horticulturalist who settled in Philadelphia in America in 1797, aged just 21. They are closely related to berberis and most have prickly foliage, although their stems are smooth to the touch. They combine handsome evergreen foliage and early scented yellow flowers, followed by clusters of blue-black berries, which makes them a good shrub to plant for a striking winter garden.
The history of mahonias
Like many woody plants, mahonias found themselves on opposite sides of the world after continental drift caused America and Asia to separate and form two separate entities. The genus developed in different ways, on opposite sides of the world, over millennia.
The most widely grown American species is Mahonia aquifolium, a low-growing, suckering evergreen that produces fuzzy yellow flowers early in the year. Blue-black berries follow and, in their native land, the fruits were eaten by American tribes so it became known as the Oregon Grape. Indigenous tribes also made a yellow dye from the bark.
American mahonias in Britain
Mahonia aquifolium, introduced into Britain in 1823, is often used by British landscapers in municipal planting because this knee-high evergreen is extremely hardy and tolerates a variety of soils and situations. However it’s usually left to its own devices when planted on roundabouts, in car parks or close to supermarkets, so it can look a little shabby through neglect. In the garden setting, regular tidying of the foliage is required because, like all evergreens, Mahonia aquifolium will shed some foliage throughout the year. It has a suckering habit, so it will spread outwards.
The best garden form of M. aquifolium is ‘Apollo’, selected and named in 1979. This forms a slow-growing, dense shrubby bush with green foliage that colours up to bronze in autumn. Scented clusters of golden-yellow flowers, with a lily of the valley scent, appear in January, February and March. ‘Apollo’ also has rounded clusters of black grape-like berries.
Mahonia japonica have upward splays of vivid yellow flowers.
Asian mahonias in Britain
Asian mahonias, such as Mahonia japonica, tend to be more spectacular in form. They have much bolder foliage, a strong architectural framework and slender fingers of flower that splay upwards. The early scented flowers are more of a delicate yellow so Asian mahonias and their hybrids are highly popular winter-flowering plants. They are easily grown and they don’t sucker. They flower in shade and rarely fail. Many new Asian species have been introduced in recent years and Burncoose Nursery in Cornwall have an up to date selection of rarer Asian mahonias, as well as garden favourites.
Sadly some of the most handsome Asian mahonias are not truly hardy, probably because oriental winters tend to be drier and colder. The finest is often considered to be M. oiwakensis subsp. lomariifolia, a species from Yunnan in southwest China. Seeds were introduced into Britain in 1931 by Lawrence Johnson, then owner of Hidcote Manor in Gloucestershire. He was among the first to grow it and his original plant still flourishes at The National Trust’s Hidcote Manor in Gloucestershire, in a very sheltered position against a wall. It has an open habit and long leaves consisting of up to 20 pairs of toothed, bright green leaflets. The clusters of long, rich yellow flower spikes appear in mid-autumn through to midwinter, like a giant mimosa.
Once these Asian mahonias began to be grown in British gardens and nurseries hardy, bee-pollinated hybrids occurred. The first hybrid seedlings were spotted at the Slieve Donard Nursery in Northern Ireland in the 1950s. Some of these seedlings were purchased by Messrs L. R. Russell’s Richmond Nursery in Surrey. These shorter bushier hybrids were more floriferous and many flowered in winter.
Some of these seedlings were passed on to Sir Eric Savill, creator of the woodland garden in Windsor Great Park and one particular one stood out. This was named M. x media ‘Charity’ by Sir Eric, due Mr Russell’s generosity (or foolishness) at giving it away. It proved an appropriate name, for the Slieve Donard Nursery got little reward from their terrific seedling. In 1984 the nursery’s owner Lesley Slinger realised his mistake although he went on to name 'Winter Sun' in 1984. This has brighter yellow early flowers and many think it better than ‘Charity’.
Purists prefer the more upright, brilliant yellow flowers of ‘Lionel Fortescue’ the man who established The Garden House at Buckland Monachorum in Devon. ‘Buckland’, another seedling from The Garden House, is worth seeking out for its pallid-yellow flowers. The completely hardy named forms of Mahonia x media provide scented winter flowers between November and February. If you’re planting for flower, opt for one of the four named forms - ‘Buckland’, ‘Lionel Fortescue’, ‘Winter Sun’ or ‘Charity’.
Mahonias generally have very prickly foliage, but there is an exception called Mahonia eurybracteata subsp. ganpinensis ‘Soft Caress’. This was voted Plant of the Year at the Chelsea Flower Show of 2013 and it’s now widely available. It’s compact, reaching three feet or so, so it could be grown in a container or close to a path. The foliage is almost feathery with narrow leaflets and the racemes of bright-yellow flower begin from August onwards. ‘Soft Caress' was discovered in 2001 by Karen Reiter Stever of ItSaul Plants, LLC of Atlanta, Georgia as a naturally occurring whole plant mutation, or sport. It needs a sheltered position away from cold winds in this country.
Mahonia varieties to plant
For winter flowers
M. x media ‘Winter Sun’ AGM
It’s early to flower and holds its clear yellow flowers well above the foliage. Up to 4m x 4m / 13 ft x 13ft
Toughest of all
Mahonia aquifolium ‘Apollo’ AGM
The Oregon grape succeeds anywhere, making good ground cover. Tidy it up and remove shabby foliage to keep it looking pristine. 1m/ 3ft
Mahonia japonica AGM
The yellow flowers have the best lily of the valley scent, even in shade, and this architectural mahonia provides a strong presence. Remove one or two older stems at the base in spring if needed. 2m/ 6ft
A softer variety
Mahonia eurybracteata subsp. ganpinensis 'Soft Caress'
This non-prickly mahonia has finer foliage. But do choose a sheltered position away from cold winds. Good in a container. 120cm / 4ft
Mahonia x wagneri ‘Pinnacle’ AGM
Combines blue-green leaves and shorter racemes of bright-yellow flowers between February and April. Not as hardy as many. 2.5m/8ft
Mahonia nitens ‘Cabaret’ AGM
A brand new introduction with holly-like foliage and a very compact habit. Spring flowers are orange-red in bud, on tall spikes, opening yellow. 1.2m/4ft
Pallid yellow flowers
The pallid-yellow flowers, huge leaves and strong shape of this mahonia make a good winter feature in larger gardens where there’s room for the splaying stems. 1.2 - 1.8 m/ 4 - 6ft
Visit our winter gardening section for more tips and planting strategies, or our plants section for a range of growing guides.