When you have a smaller yard, you want every plant to earn its keep. With fragrant yellow flowers, blue berries, and green leaves that turn purple in winter, Creeping Mahonia (aka Oregon Grape, Mahonia repens) definitely deserves a spot!
These are low-growing plants, about 12” to 18” tall, with underground stems (stolons) that spread up to three feet in width. Spring brings an abundance of small, deep yellow flowers, attractively set off by the dark green leaves. By late summer, these mature into clusters of small, dusty-blue berries that are sour but edible. (A similar species, M. haematocarpa, has red berries). The holly-like foliage persists into winter, turning a lovely plum with the advent of cold weather.
Mahonia is native to the western U.S., including Colorado, so it is easy to grow here. It’s hardy to USDA zone 4, but choose a more sheltered spot in zones 4 and 5. A moist, acidic loam is appreciated, and results in the most luxuriant foliage, but average garden soil—even clay—will suffice. Plants can be quite drought-tolerant if necessary, and do well in sun (with more water) or shade. We included several plants on the north side of our house where they get sun in summer but not in winter. Unfortunately, I’ve discovered that the evergreen leaves tend to turn brown and crispy if exposed to drying winds during freezing weather.
Creeping Mahonia makes an excellent groundcover, providing a layer of undergrowth for a natural look. The flowers brighten shady spots, and the leathery leaves offer shelter to birds and other small animals. The blossoms provide native bees species with a much-needed source of pollen and nectar. You can even make a yellow dye from the stems.
Problems are few. Apparently, the plants don’t taste very good, as they’re deer and rabbit resistant (even our ravenous rabbit herds have ignored them). You may see an occasional aphid, whitefly, or scale insect. I’ve already mentioned that the leaves have a tendency to scorch in winter. Finally, watch for chlorosis when grown in alkaline soils—an application of chelated iron may be needed.
All in all, when it comes to small shrubs and groundcovers for Colorado, Mahonia repens makes my “A” list. Try it and see if you agree!