I grew up in a small suburb just outside of Seattle where the local flora and fauna was rich and diverse. As a child I was forever pushing seeds into the soil, playing endless games in the woods amidst sensational ferns and evergreen trees, and, in late summer, picking various wild berries for dessert or for play.
Much to my mother’s irritation, I especially loved the silvery purple berries on the spiky native Oregon Grape Mahonia aquifolium shrubs that grew everywhere in our neighbourhood. They were delightfully useful, when squished in abundance, for marking the wooden planks in our communal treehouse, but disastrous when applied not always accidentally to clothing. Despite the pure joy of making that almost-indigo mess, I was not enamored of their structure and considered them rather ugly.
As an aspiring garden designer, therefore, I was fascinated to discover that people actually planted Mahonias in their gardens intentionally, and my opinion unchanged, I was not convinced that they had a proper role until I moved to Denmans Garden. Here they are very much a part of the Garden’s structure that enriches its beauty year-round, especially in late summer through December when they bloom. Their bright yellow flowers are small, arrayed in spikes or clusters, and attractive to bees, butterflies, ladybirds, and other pollinators. The berries are popular with birds as well as impish children. There are several species in the Garden, some of which began blooming as early as September and have finished by now, while others are still blooming vigourously.
Mahonias are architectural evergreen plants, meaning they have a strong presence in the garden due to their unique and distinctive shapes that provide contrast and texture. Mahonias, generally have a spiky effect, with leaves made up of glossy, jagged leaflets reminiscent of holly leaves that are arranged along long petioles. There is always an exception to the rule, however, and in this case, it is ‘Soft Caress’ (Mahonia erybracteata subsp ganpinensis to those who can pronounce it) which has a soft, flexible habit and fine, willowy leaves that respond gracefully to even the slightest puff of wind. John Brookes loved this species, and we have planted it in the Lower Nut Walk and at the top of the East Riverbed where its fernlike texture contrasts with mossy river rocks. By contrast, this species is smaller than the very tall Mahonia x media ‘Charity’, which has grown up to 10 feet tall near Clock House.
While easy to grow in well-drained soil, Mahonias prefer protection from winter winds. Hardy to -15 degrees Celsius (5 degrees Fahrenheit), they are not fussy about the pH of the soil and thrive in sandy, loamy, and clay soils as long as they are not water-logged. They even grow well in pots. We grow them in full sun with fairly dry conditions and in dry shade and part-shade where they flourish.
The genus is named after botanist Bernard McMahon, who was considered to be President Thomas Jefferson’s mentor. Among other achievements, McMahon was curator for the plants collected on the Lewis and Clark expedition in the early 1800s and author of American Gardener’s Calendar (1806) which was ‘the most comprehensive gardening book published in the United States in the first half of the nineteenth century’.
