910 Buxus microphyllaCommon Names: littleleaf boxwood, small-leaved boxwood, boxwood Family: Buxaceae (boxwood Family)
The boxwoods are profusely branched evergreen shrubs widely used in landscaping, especially for hedges and foundation plantings. There are some 70 species of boxwoods, but only two are commonly found in cultivation: this one and common boxwood (Buxus sempervirens). But those two species have given us hundreds of botanical varieties, horticultural cultivars and hybrids of garden origin to choose from. All the boxwoods have small, opposite, evergreen leaves. They produce small star shaped yellowish green pistillate (female) and staminate (male) flowers on the same plants. The flowers are not showy, but are quite fragrant. The star points are actually sepals - boxwood flowers have no petals. The flowers are in clusters consisting of a single female flower in the center, surrounded by several male flowers, recognized by their conspicuous yellow anthers. Littleleaf boxwood has very small leaves, just 3/4 in (1.9 cm) long, and considerably thinner in texture (almost transparent) than those of other boxwoods. They are elliptic-oblong, and dark green, usually turning a rather ugly bronze in winter. Littleleaf boxwood grows in a dense rounded mound, 2-3 ft (0.6-0.9 m) tall and 3-5 ft (0.9-1.5 m) across.
The classification of the boxwood cultivars is extremely confused and the experts have differing opinions on which cultivar belongs to which species or variety or hybrid. The Royal Horticultural Society Dictionary of Gardening recognizes three botanical varieties: var. koreana (sometimes listed by others as B. sinica var. insularis) which has leaves that are rolled slightly downward and includes the most cold hardy selections; var. sinica (Chinese boxwood) which is a larger shrub or small tree to 20 ft (6.1 m) tall, with an open, spreading habit; and var. insularis which has larger, somewhat leathery leaves and pubescent twigs. Some authorities list several boxwood cultivars under B. microphylla var. japonica, but the RHS places those cultivars in a different species, B. harlandii (Harland boxwood). Cultivars listed under B. microphylla var. koreana include: 'Winter Green' which gets 3-4 ft (0.9-1.2 m) tall and wide, and is extremely cold hardy with foliage that stays dark green all winter; and 'Tide Hill' which gets only about 1 ft (0.3 m) tall but spreads out to 4-5 ft (1.2-1.5 m) across. Cultivars listed under B. microphylla var. insularis include: 'Green Gem' which is a small plant with narrow, olive green leaves; and 'Pincushion' which has leaves about 1/3 in (0.8 cm) long and grows in a low mound about 2' across. Cultivars listed under the nominate variety (B. microphylla var. microphylla) include: 'Compacta' which is extremely compact and dense, with tiny 1/4 in (0.6 cm) leaves and grows slowly to just 12 in (30.5 cm) in height; and 'Curly Locks' which has twisted branchlets and gets 3-4 ft (0.9-1.2 m) tall. Cultivars listed under Harland boxwood (B. harlandii) by the RHS, but listed as B. microphylla var. 'Japonica' by other authors include: 'Rubra' which has yellow-orange foliage; 'National' which has a tall, erect habit to 15 ft (5.6 m) in height; and 'Kingsville Dwarf' which has tiny leaves only 1/5 in (0.5 cm) long.
Common boxwood, a somwhat larger, more open shrub with slightly larger leaves, has even more cultivars, and there are several cultivars selected from hybridization between common and littleleaf boxwood. We said it was confusing!
Littleleaf boxwood has not been found in the wild. It has been in cultivation in Japan since at least the 1400's, but no one knows where it originally came from - China, Korea, Japan? Perhaps it was created by gardeners by hybridizing and/or selecting other species, or perhaps it has simply gone extinct in the wild.
CultureLittleleaf boxwood responds very well to pruning. Hedges and plants used for edging can be trimmed in summer. Hard, rejuvenating pruning and major shaping should be done in late spring and followed by a dose of fertilizer and mulch. Don't cultivate around the shallow-rooted boxwoods. Light: The boxwoods, including littleleaf boxwood, do well in partial shade. Newly transplanted plants especially, should be protected from midday sun. Established boxwoods do fine in full sun up North, but should be positioned in partial shade in the South. Moisture: Boxwoods have shallow roots, so they should be mulched well and watered when the soil gets dry, especially if positioned in full sun. Hardiness: USDA Zones 5 - 9. The cultivars of var. japonica are the most cold-hardy, and some of them are reported to be hardy to zone 4. Propagation: Boxwood cuttings are fairly easy to root; take semiripe tip shoots in summer and root in a moist potting medium under mist or under a plastic "tent." The species and even some of the cultivars can be propagated from seeds, which require 2-3 months of chilling before they will germinate.
The boxwoods are among the most common hedge plants, but they also can be used for almost any landscaping application. Individual plants or small groups, unpruned, make fine specimens in dappled shade; planted close together and pruned to a smooth, undulating surface, boxwoods make a striking ground cover; the small cultivars can be used in knot gardens or as edging around borders. Boxwoods are, of course, the quintessential foundation plant, used to hide home foundations in American suburbs throughout most of the United States Boxwoods are commonly used for topiary and they are well suited for bonsai. Littleleaf boxwood is especially well suited for shaping because its leaves are small and don't look ragged after trimming as do plants with larger leaves.
Littleleaf boxwood has a fine texture and a symmetrical and formal habit. It is a landscaping workhorse. The fragrant blossoms, although not showy, attract bees.
Contact with the sap of boxwood may irritate the skin in some people.
Steve Christman 2/9/01; updated 12/18/03, 11/4/12, 3/23/18