BERNARD McMahon was 21 when he left Ireland for the United Sates, two years ahead of the 1798 rebellion. Unfortunately, the many accounts of his glowing career don’t record where he was born or what he got up to before emigrating. Perhaps I’ll claim him for my part of Co Down and open the money-spinning Bernard McMahon Garden Museum?
It can be assumed, however, that McMahon knew something of horticulture, botany or both before arriving and settling in Philadelphia, as within six years he was publishing a catalogue featuring 720 species and varieties of seed – the first list of its kind published in America.
McMahon subsequently struck up a friendship with Thomas Jefferson, the third president of the United States, whose Monticello hilltop homestead, at the centre of a Virginia tobacco plantation, had an impressive garden. The Irishman mentored Jefferson via regular correspondence and no doubt the president had his own copy of the 1806 classic The American Gardener's Calendar: Adapted to the Climates and Seasons of the United States – or what became known simply as ‘the Calender’. It was published over 11 editions for a further 50 years. The book provided month-by-month and step-by-step instructions on planting, pruning and soil preparation for both edibles and ornamentals. A sort of proto-Casual Gardener, if you like.
The Calendar even featured a chapter on garden design, where the author appears to be a forerunner of fellow Irishman William Robinson, who decades later went on to popularise naturalistic design and planting.
McMahon urged his readers to "consult the rural disposition in imitation of nature” instead of adopting the predominant European formal and geometric style. He also advocated the use of native species over those from outside North America. There have been suggestions that McMahon’s Calender wasn’t entirely his own work and borrowed extensively from the work of English authors – a practice which no doubt persists today.
But McMahon was nothing if not enterprising and 1808 he bought 20 acres to set about creating a nursery and botanic garden, which he named Upsal Botanic Garden. This was his base for just eight years until his death, aged 41, whereupon the nursery business passed to his wife. Their son Thomas P McMahon continued to update and publish the Calendar.
McMahon Snr’s contribution to American horticulture was recognised two years after his death when in 1818 botanist Thomas Nuttall bestowed the genus name Mahonia on a group of evergreen shrubs that remain a common sight everywhere from the United States to Belfast city centre.
Boasting yellow flowers in spring with a scent reminiscent of lily-of-the-valley followed by blue berries, mahonia is a close relative of berberis. Its glossy, evergreen leaves look a bit like holly, with symmetrical pairs of spiky leaflets. If the winter is cold enough, the foliage becomes reddish or purple. The small bell-like flowers last several weeks before giving way to the fruit, which is prized by birds.
Generally unfussy about soil, mahonias are most content in at least partial shade and should be protected from cold winds. Recommended varieties include the statuesque Mahonia japonica, with lemon-yellow flowers succeeded by an abundance of purple fruit, and the hybrid Mahonia x media 'Winter Sun’, with even brighter flowers. Mahonia aquifolium – AKA the Oregon Grape – originates in McMahon’s adopted home, though on the opposite coast from Philadelphia. Recommended for taller ground cover, it reaches a metre in height in is one-and-a-half times as wide.
