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For the Love of Holly |
By Margaret Page Culver, Master Gardener, and Carl Wilson, Horticulture Agent, Colorado State University Cooperative Extension, Denver County
Many gardeners love holly and would do almost anything to grow it. Unfortunately, Colorado is not holly country.
This evergreen shrub is much loved for its shiny green leaves, both attractive for its persistence and repellant because of their don't-touch-me spines. Berries of red, orange, white or black offer as much to birds as they do to people who want foliage sprays for holiday decoration. However, Colorado gardeners need to know the risks of attempting to cultivate holly here. Colorado's intense winter sunshine, low humidity and drying winds disfigure or kill the foliage of broadleafed evergreen plants, such an hollies and rhododendrons. These broadleaves are native to humid climates where winters generally are cloudy and plants grow in the sheltered understory of deciduous forests.
In addition to climate, Dr. James Klett, Colorado State University Cooperative Extension specialist for landscape plants, says alkaline clay soil is the other strike against growing healthy hollies. As a rule, hollies require slightly acid, well-drained, humus-rich soil.
So, you may ask, what can be done to grow this prized plant? It's essential to choose a protected area as a safeguard against high winds and to amend soils with organic matter before planting. Even so, many gardeners may be disappointed by the amount of winter die-back found on their Meserveae hollies. If you are someone with the right planting site and excellent soil, here are some other growing guidelines:
- Of the true hollies, only I.meserveae grows relatively will here This species produces small, glossy, bluish-green leaves and red berries.
- Hollies have separate male and female plants. Only one male plant is required for a cluster of five female plants. Only one male plant is required for a cluster of five female plants to provide the pollen that will produce berries.
- Possible male/female choices include 'Blue Boy'/'Blue Girl', and 'Blue Prince'/'Blue Princess', both pairs growing to 10 feet. The royal pair is reported to bear more abundant fruit.
- Although not a true holly, grape hollies are more suited to the needs of most Colorado gardeners. Both the native creeping grape holly (Mahonia repens) and Oregon grape holly (M. aquifolium) are much less demanding. This plant bears shiny green, spiny leaves that turn a rich burgundy in the fall. Blue berries follow clusters of bright yellow spring flowers with a single bush producing berries. Some protection for the foliage is needed but the plants are better adapted to alkaline soils and thrive on less water.
Whether you choose the challenge of growing Meserveae holly or opt for the easier cultivated Grape holly, both offer the bird feeding and foliage decorating advantages that allow gardeners to sing its praises.
Photograph courtesy of Judy Sedbrook.
