Strawberry Tree (Arbutus unedo)
The strawberry tree has laurel-like, dark green, glossy, leaves about 2 to 3 inches long. Urn-shaped flowers typical of many ericaceous plants (from the Ericaceae family) are borne in clusters of 10 to 30. Fruit with a rough, warty outer surface starts out green, and then changes to yellow, gold, and then red as it ripens. In spite of the common name, the round, three-quarter inch fruit only superficially resembles a strawberry. Although it is edible, it is more popular with the avian population than it is with us humans. Hailing from the Mediterranean region, western France and western Ireland, it is perfectly at home in USDA Zones 8 through 10, and possibly 7 with protection. Give it plenty of room to grow, for it can reach 8 to 30 or more feet tall and wide.
The trunk itself adds interest as it becomes gnarled and twisted with age. Thin plates of the grayish-brown bark exfoliate, and the attractive reddish young bark that lies beneath it is revealed. Interest is compounded by the fact that the fruit ripens at the same time new flowers are produced.
Provide full sun or partial shade for the strawberry tree. It prefers well-drained, acid soil. Established plants have long tap roots that help to make them drought-tolerant and wind-resistant. Moderate salt tolerance makes it a good choice for people who must deal with salt-laden winds or de-icing salts. Deer are not particularly attracted to the foliage, and this may be an important consideration in areas where deer are apt to browse.
The plant grows naturally into a formal, rounded shape, but selective pruning can be done to train it into a standard that will reveal the attractive trunk. Pests and diseases rarely attack the strawberry tree. Propagation is from seeds, which germinate readily, and by cuttings of half ripe wood taken in summer or early fall.
A few cultivars can be found that may meet special needs. If the full-sized shrub seems too large for your garden, select the slower growing ‘Compacta', which tops out at 6 to 10 feet tall and wide. The compact form in no way lessens the visual impact of the contorted, picturesque branching structure. ‘Elfin King' is a commonly available compact form that fruits and flowers heavily and matures at anywhere from 5 to 10 feet tall and wide. ‘Oktoberfest' grows 6 to 8 feet tall and wide and bears pink flowers. ‘Rubra', a form that seems less vigorous and hardy than the species, bears deep pink flowers and is very hard to find in commerce.
Texas madrone (Arbutus xalapensis) is native to Texas, New Mexico, and from Mexico to Guatemala. Growing 20 to 30 feet tall and wide, it shares many characteristics of the strawberry tree. Clusters of white or pale pink flowers bloom in spring and show up well against the glossy green leaves and attractive bark. Bark changes color during the year, beginning when it is young with creamy colored bark, then changing to pink and then brown. Peeling bark reveals new bark beneath. This species grows well in the chalky soils of the region.
Arbutus andrachne, madrone or Greek strawberry tree, also shares many characteristics of the strawberry tree. Growing 10 to 20 feet tall and wide, it bears flowers in spring and orange-red fruit that is smoother than A. unedo. Native to southeastern Europe and southwestern Asia, it grows best in Zones 8 to 9 and possibly in protected spots in Zone 7.
A naturally occurring hybrid between Arbutus unedo and A. andrachne (Arbutus ×andrachnoides) is probably best in the cooler regions of the United States. Flaky, cinnamon red bark exfoliates to reveal a smooth layer of lime green to yellow patches of new bark. It does not bear fruit as heavily as A. unedo, but it makes a fine specimen that grows up to 30 feet tall and regales passersby with its sinuous, almost serpent-like trunk.
The Pacific madrone (Arbutus menziesii) is found in the western regions of North America from southern British Columbia to central California. Growing up to the size of an oak tree, the fruit is attractive to many birds and other wildlife. Unfortunately, its range is diminishing as a result of fewer natural fires that keep competing conifer overstory at bay.
The Arizona madrone (Arbutus arizonica) is a small to medium tree that grows from 40 to 50 feet tall and has a crooked trunk and twisted, gnarly branches. Its range is in the foothills and lower mountains of southern Arizona and New Mexico and continuing on down into northern Mexico. The mealy, sweet berry is important to some wildlife species.
Arbutus canariensis (Canary madrone) is endemic to the Canary Islands. A. peninsularis is found in the Baja California Peninsula of Mexico, while A. glanulosa is found primarily in central and southern Mexico.
The Emperor Moth and other Lepidoptera species use the Arbutus species as food plants. The Straits Salish people of Vancouver Island used the arbutus bark and leaves for several medicinal applications, including colds, stomach problems, and tuberculosis. Arbutus wood burns hot and long and is consequently a great fuel wood. However, it has little value in the building industry because the twisted and gnarled trunks do not produce straight timbers.