The graceful Mahonia is native of Mexico, a member of the Berberidaceae family and it’s a stellar part shade performer in the Mast Arboretum. While it can take full sun once well established, it’s probably best in part shade. Our oldest plant is placed in the worst possible site imaginable: a hard-packed, beat-down east Texas red clay right on the very edge of a hot parking lot in full sun. I laid a thermometer there one time and the lower branches were resting right next to 140 degree asphalt. Plant remained cheerful. July is miserable in Nacogdoches and summers can be brutally dry. Not only that, the spot is out of reach of the nearest solid-set sprinkler head. When Texans say that the 100+ degree heat is killing us, we mean it. We planted a small one-gallon plant in 1988 as a companion to a strange “shrub oak” from Mexico and then mulched the area heavily with three to four inches of composted pine bark. While the oak is history, the Mahonia has slowly matured into a 4′ tall and 6′ wide specimen.
Old scanned in photo from a long ago expedition to Mexico with Lynn Lowrey and Alice Staub taking pics of a Mahonia gracilis clinging to a rocky face.
Given a modicum of horticulture, this evergreen plant has a lot to offer. In good morning sun, new growth is a glossy and lustrous lime-green. In shade, the plant sports darker foliage with that same glossy nature. Unlike most Mahonias, there are no prickly leaf edges or thorny branches to work around. The graceful Mahonia, is smooth and soft to the touch.
Mahonia gracilis on a mountain side east of Saltillo.
On one expedition in the 1980’s, one of the most striking plants I encountered in the San Madre Oriental mountain range, western side, and up on a dry slope was a graceful Mahonia gracilis in full bloom. In this shady moist canyon, foliage color was amazing – clean and blue – which set up the perfect contrast for a celebration of bright yellow flowers. In the SFA Mast Arboretum, the winter interest is terrific for plants receiving morning and noon sun, a mixture of reds, oranges, yellows and light green. Plants grown in part-shade tend to be taller and open and fall color less exciting. Full morning sun, mulch, and an occasional irrigation in the worst of droughts is the best recommendation. Late-winter flowers are bright yellow and held on slightly erect racemes emerging from near the terminal buds. We have failed to successfully root a cutting and because of the early-womter blooming nature of the plant, we’ve failed to make seed. However, the long graceful shoots lend themselves to layering in nearby mulch, and plant numbers can be produced modestly in that manner.
Mahonia gracilis in full sun at the Mast Arboretum.
Actually, there are many Mahonias that should be planted in Texas for part shade winter and early spring interest. When planted in mass, few plants make a stronger impression. Mahonia fortunei has been dependable, although the 1989 zero degree event killed a few plants and burned many. There are several hybrids worth seeking: Mahonia X media cultivars ‘Underway’, ‘Winter Sun”, and “Lionel Fortescue” have performed well for years. The hybrid between Mahonia bealei and M. lomariifolia “Arthur Menzies” is a knockout. M. bealei is a commonly used shrub to 6′ with strong architectural interest. M. trifoliata, a native of Texas and Mexico with sweet edible fruit, has performed well in the dry garden and sports a blue cast to the foliage.
Mahonia trifoliata at SFA Gardens
Finally, a most interesting naturally occurring hybrid is M. trifoliata X M. swaysei which was given to us by Logan Calhoun many years ago, a plant that has survived for over a decade at the front of the Mast Arboretum in a sunny, very well drained spot along Wilson Drive. Small and shaped like a meatball, we have yet to get viable seed and my skill at cutting propagation has been poor.
M. trifoliata X M. swaysei, a naturally occurring hybrid in Central Texas.