Extension Service Garden Hints

Try perennial hebes for a new source of fall color

CORVALLIS, Ore. – There's always something new for gardeners to try. Hebes are a group of evergreen shrubs native to New Zealand. Most hebes flower in the summer, but some bloom in late fall. Some have foliage that provides vivid fall color.

Both the flowers and foliage of these evergreen shrubs can provide an interesting change from the usual asters and maples we customarily rely on for autumn interest.

Although many hundreds of hebe cultivars have been developed, only a very few are familiar to most American gardeners. Hebes may have acquired a reputation for lack of hardiness because some of the most popular cultivars introduced here "are certainly not hardy in very cold winters," explained Neil Bell, consumer horticulturist with the Oregon State University Extension Service.

Fortunately for gardeners in the Pacific Northwest living west of the Cascades, hebes are quite hardy. In most of the colder regions of North America, most hebes are not suitable, because most climates outside Pacific Northwest's maritime areas are either too hot in the summer or too cold in the winter.

Bell says there is a general rule of thumb for judging how hardy a hebe variety is. Large-leafed hebes are less hardy than small-leafed hebes. Some of the large-leafed hebes can be injured by temperatures below 25 degrees, Bell says. He suggests that rather than avoiding them altogether, consider putting these tender plants in a sheltered spot.

For showy purple flowers in the fall, Bell suggests the hebe cultivars "Amy" and "Alicia Amherst," both commonly available at local nurseries. These feature spikes of purple to violet flowers in summer and early fall. "Purple Picture" blooms in June but flowers profusely again in October and November. "Mohawk" blooms profusely into November.

Some red-flowering hebes provide color through November and even through December in a mild year. Bell suggests "Hobby" or "Simon Delaux." "Bowles' Hybrid" produces lavender flowers in summer, but will bloom again in the fall, even into January. Except for Bowles' Hybrid, which is hardier, all these hybrids are decidedly susceptible to cold. So plant them against a sheltered wall out of the wind or tucked between other sheltering shrubs. Be prepared to give them a little extra cover if the temperature threatens to drop suddenly.

Several small-leaved hebe cultivars that are hardy throughout the region west of the Cascades have beautiful and unusual foliage. Some of these are fairly commonly sold in the Pacific Northwest. "Quicksilver," as the name suggests, has small silvery leaves. "Boughton Dome" has grayish foliage. "James Stirling," which resembles a small conifer, has ochre leaves.

Another unusual characteristic of some hebes is a noticeable change in foliage color from summer to winter. Some hebe cultivars take on a purplish or reddish cast to the foliage during the winter. Perhaps the best known of these is "Caledonia," which turns an attractive purplish color. "Sapphire" has shoots that turn bright red at the tips in the winter.

Several of the variegated cultivars of hebe are beautiful and unusual, but these are large-leafed, tender hebes and require a protected spot if you want them to survive the winter. "Silver Queen" (also called "Franciscana Variegata"), has cream-colored edges to the foliage. "Tricolor" is a commonly available variegated cultivar in which the leaves are a mix of red, cream, and green. "Andersonii Variegata" is a larger plant than the other variegated ones mentioned above, reaching four feet. Its leaves are edged with cream, and it also produces light blue flowers in the fall.

In addition to a protected location, Hebes need at least partial sun and well-drained soil. You'll also need to water them during the summer months. Most do well without much pruning. But to keep them from becoming leggy or to keep them the size you want, annual moderate pruning after they bloom works well.

The OSU Department of Horticulture's "Landscape Plants – Images, Identification and Information" website has photos and other information about several kinds of hebes that grow on the OSU campus in Corvallis. Go to: http://oregonstate.edu/dept/ldplants/

By: Davi Richards
Source: Neil Bell

Email this story

Printer-friendly version

News & Garden Archives