Plant profile: mahonia
Noted for their bold architecture and year-round colour, many mahonias have fragrant flowers in winter
With dramatic foliage and striking flowers, mahonias provide welcome winter colour and even fragrance
The most architectural forms of Mahonia are widely planted for their bold, primeval appearance and their flowers, which appear on long racemes from a central ruff of spiny leaves in autumn and winter followed by clusters of long finger-like projections of dark-purple berries. Others are more shrub like with short congested racemes; the leaves often turn red in cold weather. When the plants we now know as Mahonia were first introduced to cultivation they were included in the genus Berberis where several botanists now think they should return. The name Mahonia was introduced in 1818 when the botanist Thomas Nuttall renamed the species Berberis aquifolium as Mahonia aquifolium; today Mahonia includes around 70 species, divided into two main groups: Orientales from Asia and Occidentales from Central and North America.
Two species M. japonica and M. oiwakensis subsp. lomarifolia, both excellent garden plants in their own right, have been hybridised in several locations, at different times, creating M. x media. The best named forms, are regularly planted in large parks and gardens, including the successful selections M. x media ‘Charity’. This was one of three selections (the others were ‘Faith’ and ‘Hope’) chosen in the early 1950s by Sir Eric Savill, Keeper of the Gardens at the Crown Estate, Windsor, and his head gardener Hope Findlay, from a line of seedlings growing in the Surrey nursery of Messrs LR Russell. The seedlings had been bought from the Slieve Donard Nursery in Northern Ireland, which also produced another M. x media cultivar with similar attributes but more upright racemes named ‘Winter Sun’.
Two more M. x media cultivars appeared as the result of hybridisation by Lionel Fortescue at The Garden House in Buckland Monachorum in Devon. Of around 200 seedlings that germinated, only five were retained. The most outstanding with an imposing inflorescence up to 70cm across, composed of 13 or 14 numerously branched racemes was named ‘Buckland’. Lionel Fortescue gave another of his seedlings to The Savill Garden, which also proved to be an outstanding selection with dense sheaves of erect, highly branched racemes of fragrant flowers, up to 40cm long, and was named ‘Lionel Fortescue’ in his honour.
Several garden- worthy cultivars have also arrived from the USA, including M. ‘Arthur Menzies’, a chance hybrid selected in 1964 at the University of Washington Arboretum. In 1961 the supervisor of plant accessions at San Francisco’s Strybing Arboretum, Arthur Menzies, had sent seedlings from his garden to Washington Park Arboretum. After growing these seedlings on for a year, staff at the arboretum noticed that one of the plants had foliage more reminiscent of M. bealei, which was more cold hardy than the other parent, M. oiwakensis subsp. lomarifolia. Arboretum staff suspected this to be a hybrid, a fact confirmed a few years later when cold temperatures in December killed the other seedlings but left the mystery plant almost intact.
Another spontaneous hybrid M. x lindsayae ‘Cantab’ appeared among M. siamensis seed sent by Nancy Lindsay from Jardin Serre de la Madone in Menton, France (previously home to Lawrence Johnston), to Cambridge University Botanic Garden. In 1964, the Garden’s taxonomist, Peter Yeo, noticed one was not the species but an obvious hybrid between M. siamensis and M. japonica (which is now thought to be the same species as M. bealei). He named this hybrid M. x lindsayae in honour of Nancy Lindsay and gave it the cultivar name ‘Cantab’ after the university. Although M. siamensis is tender, ‘Cantab’ has proven to be hardier, though it still needs some shelter.
Whether chance seedlings or intentional hybrids, mahonias never fail to please, especially in these dark, cold winter months, when they contribute to the garden in both flower and fragrance.
• Author Matthew Biggs is a Kew-trained gardener, TV presenter and the author of several books. He is also a regular panellist on BBC Radio 4’s Gardeners’ Question Time. His recommendations for the best mahonias continue over the next five pages.