Marvellous Mahonias

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Mahonias are reliable shrubs for cheering us up in winter when many of them flower. Pictures of several different ones have appeared on GOY recently so I thought I would put together (with a little prompting from another member) a blog on some of the most common ones.

There are around seventy species of mahonia occurring in rocky places and woodland in the Himalayas, eastern Asia, north and central America. They have evergreen foliage, often very attractive with sharply toothed leaves (beware of weeding among old leaves, they are still sharp!), fragrant yellow flowers in the main (although at least one species has red flowers) followed by decorative blue, purple or black berries. In the more upright varieties, the deeply fissured bark can also be attractive. They prefer a moderately fertile, humus-rich, moist but well-drained soil in full or part shade but some will tolerate sunny positions as long as the soil remains moist. Some are quite hardy, taking at least -20C while others require a more sheltered spot, out of the way of cold winds. Although they can be planted at any time, spring and autumn are the best times to get them established while the soil is warm and moist. All are very tolerant of pruning; this should be done as the flowers fade, cutting immediately above a leaf joint.

M.aquifolium (common name Oregon Grape) is a suckering shrub around three feet high and up to five feet across. The flowers are borne in dense clusters in spring; leaves often turn red-purple in winter. This one can put up with pretty hostile conditions but will not grow or flower as well as in a better spot. The variety ‘Atropurpurea’ has leaves that turn a dark red-purple in winter while ‘Orange Flame’ has rust-orange young foliage, turning red in winter. ‘Smaragd’ is a smaller plant with large clusters of flowers as is ‘Apollo’ with bronzy young foliage. All these may suffer from mildew if the soil is too dry.

(Mahonia aquifolium – photo by kind permission of Chrispook)

M.confusa is another of the less hardy ones but should still tolerate
-10C in a sheltered spot when established. It can reach three to four feet with leaves more grey-green than the others. Flowers are carried from late summer into autumn.

M.fortunei is a slow-growing, upright shrub with upright flowers in early to mid autumn. It reaches four feet in height but is less hardy (although it will take about -10C)

M.japonica is much tougher and very shade tolerant. It can make a large shrub about six feet tall and up to ten feet across if left unpruned. The flowers are pale yellow and very fragrant, carried from late autumn to early spring. Leaves often take on hues of red in winter, especially in sun or on poorer soils. ‘Bealei’ has blue-green leaves and shorter raecemes of flowers.

(Mahonia japonica in Andrewr’s garden)

M.lomariifolia is another of less hardy ones, growing very erect (even described as lanky in one book) to ten feet. It flowers from late autumn into winter and needs protection from cold winds. There is a very good specimen growing in the entrance courtyard at Hidcote garden in Gloucestershire.

M.x media is a hybrid between the two previous species with the habit of M.lomariifolia but the hardiness of M.japonica. It starts flowering in late autumn and continues right through winter. ‘Buckland’ has bright yellow blooms, ‘Charity’ has particularly dense clusters of flowers, ‘Lionel Fortescue’ also has bright yellow blooms but held more upright and is often the first into flower of these cultivars, while in ‘Winter Sun’, they are dense but more arching. I have found these to get leggy quite quickly but very amenable to pruning.

(Mahonia x media – probably ‘Charity’ – in Andrewr’s garden)

M.napaulensis flowers in early to mid spring on a large shrub some eight feet tall and as much across. It is hardy to around -10C.

M.nervosa is dwarf at only eighteen inches high and suckers. The leaves are dark and glossy, often taking red tints in winter. The flowers are later in spring, continuing into early summer.

M.repens is even smaller at only one foot, again suckering to clumps around three feet across. The flowers are dark yellow, carried in spring but the leaves are more dull than glossy. It can take fairly dry soil and, with protection, will tolerate temperatures down to -15C.

M.x wagneri is a cross between the tender M.pinnata and M.aquifolium. It carries bright yellow flowers in spring over dull, dark green leaves. It has a spread of around three feet but is a little less in height. ‘Moseri’ has pale green leaves, often flushed pink or red, ‘Undulata’ is twice as tall at six feet and the leaves are a darker green with wavy margins.

I had hoped to include some photographs of the different species but only three have pictures on GOY and I don’t want to infringe copyrights by copying from other sites. I suggest you do a Google search for an image of any that take your fancy.

If you haven’t already planted one of these easy-to-please shrubs (or are considering getting another), I hope this list has been useful in narrowing the choice and clarifying the differences between them.

• 13 Dec, 2008
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