Mahonias are low evergreen shrubs with spiny-edged leaves growing 1-2 feet high and up to 6 feet wide, depending on variety. Yellow flowers appear in the spring, followed by blue or black fruit which may attract birds. The holly-like leaves turn red in the fall, then bronze in winter. Too much winter sun and wind will cause leaf edges to burn.
Mahonias are adaptable but prefer loamy rich soil. Grow in part sun to full shade. Hardy in Zones 4-7, mahonias are adaptable to low water, but plants should be watered in dry winter periods. Prune after flowering to remove old, damaged or awkward stems. Mahonias are also slow to establish.
Two varieties are recommended for Colorado: M. aquifolium ‘Oregon Grape Holly’ prefers more moisture and afternoon shade while M. repens ‘Creeping Grape Holly’ prefers full sun and little-to-no water. It spreads by underground stems, becoming an ideal groundcover under trees. Try planting with spring bulbs.
Contributed by Joan Nusbaum, Colorado Master Gardener. Photograph also by Joan Nusbaum.
To read more about broadleaf evergreen shrubs, go to: http://www.ext.colostate.edu/PUBS/Garden/07414.html. For answers to your horticultural questions, contact the Master Gardener Help Desk at 636.8921 or CSUmg2@elpasoco.com. (A version of this article appeared in The Gazette on 4/18/09.)