September 2015 in the Garden

This summer, being particularly sunny and hot, has been spectacular for fruit production. One group of plants that has benefited is the elderberries. Sambucus (elder or elderberry) is a small genus of shrubs and herbs found primarily in temperate and subtropical forested areas of Europe, Asia, Macronesia and North, Central and South America. There are two species native to British Columbia: S. racemosa and S. nigra. Throughout BC, red elder (S. racemosa) is a common constituent of the native forest, but S. racemosa is actually a variable complex of five subspecies: European red elder (subsp. racemosa), Siberian red elder (subsp. siberica), Kamchatka red elder (subsp. kamtschatica), Japanese red elder (subsp. sieboldianum), and American red elder (subsp. pubens). Our own Pacific red elder (subsp. pubens var. arborescens) is known to grow to 10 m or more in height, hence the varietal name (arborescens = tree like). We have both American and Pacific red elder in BC, and we also have a black-fruited variety (subsp. pubens var. melanocarpa) in the Rocky Mountains. There are also yellow- and orange-fruited forms of the American red elder, but they are not common enough to warrant status as varieties.

Sambucus nigra (black elder) is likewise a complex of five subspecies. This complex includes the European black elder (subsp. nigra), South American elder (subsp. peruviana), Canary Islands elder (subsp. palmensis), eastern North American black (“American”) elder (subsp. canadensis), and western North American blue elder (subsp. caerulea). Blue elder is a common shrub on Vancouver Island and in the mountains to the east of Vancouver, and especially in rain-shadow areas to the south. The berries are actually black, but covered in a fine blue wax. Like the reds, black elders are also present in the Garden, but the blacks have all been planted, whereas red elder is native to the site—even weedy here. The two species are easily differentiated, either when they’re in flower or in fruit, as red elder is earlier and has small, pyramidal flower and fruit clusters, while black elder has broad, flattened flower and fruit clusters (and edible fruit). Unfortunately, the chances of seeing red elderberries at this time of year are slim. They are among the earliest of all native fruits to ripen, doing so usually in June, and birds are quick to take them. However, both black (and blue) elderberries are abundant this year in the Botanical Garden. Look for blue elderberries in the Garry Oak Meadow and Woodland Garden and the Pacific Slope Garden, American elder in the Carolinian Forest Garden and a magnificent display of European black elder in the European Woodland.

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Submitted by Douglas Justice, Associate Director, Horticulture and Collections, August 31, 2015

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