Olives for the Northern Gardener

If you live in the Maritime Northwest, you can grow a true olive tree. The trees will begin to bear fruit in just a season or two, and you can then try your hand at harvesting and processing the olives. You can find a self-fertile Spanish variety at onegreenworld.com.

For the rest of us northern gardeners, there are several members of the olive family (Oleaceae) that we can grow, although the fruits are sweet and juicy, with no resemblance at all for those canned black olives you serve for Thanksgiving dinner. One of them, the gumi, is now growing near my bedroom window, and I expect to be harvesting its fruit in just a few seasons.

Two species of olive that grow well in the northern tier of the United States have, unfortunately, found the climate and soils too much to their liking. The billowing gray-green leaves of the Russian Olive, Elaeagnus angustifolia, and Autumn Olive, E. umbellata, can be seen along the highways, rivers and streams in many parts of the north and west, and tend to out-compete native trees and shrubs. Although both these species are still sold as ornamental plants, they are listed as noxious weeds or prohibited invasive species in many states.

An beautiful, less invasive alternative is a relative of the Russian and autumn olive, the gumi, E. multiflora. The gumi, or goumi, is a shrubby, rounded plant that will grow to 6 to 8 feet tall and wide. The spring flowers have a strong, attractive scent that is enjoyed by both bees and humans, although the flowers themselves are small and difficult to see. The fruit has a sweet/tart flavor that is said to resemble the taste of pie cherries. The fruit can be eaten fresh, made into preserves, or dried. The fruit of the gumi should be allowed to ripen on the bush, to improve their flavor, since they will be overly tart before they're completely ripe.

All of the Elaegnus species are able to grow in marginal land, and, like legumes, they form a partnership with specialized bacteria that allow them to harvest nitrogen from the air. For this reason, these plants are often used to reclaim land laid bare by strip mining. Smaller plants growing beneath these shrubs will benefit from the increased fertility. The shrubs require little supplemental water, and are hardy down to USDA zone 4, and even to zone 3 for some varieties.

If you have the room for an Autumn olive, and if this plant is not listed as an invasive species in your state, they can create a fast-growing hedge or wind screen that will provide many pounds of fruit for winter birds. Autumn olives are also delectable for humans, of course, if they are picked after they have ripened enough to lose their astringency, and before they dry on the tree. These fruits also contain a chemical, called lycopene, that has been found to protect against prostate cancer.

The gray-green leaves of these plants make an excellent backdrop for blue-flowering perennials, like Russian Sage. I suspect that they would also make a beautiful support for a blue or purple clematis. Because the gumi and autumn olive grow quite fast, they can be a good plant to grow if you've just moved to a new home and want to create a quick landscape, and the color of their leaves make a welcome change from the green leaves found on most other garden plants.

Gumi, the smaller species, will look very nice grown near a house, especially if they are sited close enough to a window for the sweet fragrance to waft through the home in the springtime. Autumn olive will need much more room, because this shrubby plant can grow as much as twenty feet high, and has been know to produce as much as 35 pounds of fruit from one bush.