Boxwood

(Buxaceae - Box Family)

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• Form
  • miniature to large shrubs, depending upon species, hybrid, or cultivar; all modern hybrids are miniature to small shrubs
  • small versions slowly grow to 2' tall by 2' wide, whereas larger versions mature after many years at 15' tall by 15' wide
  • upright oval to upright rounded growth habit
  • slow or very slow growth rate

• Culture
  • full sun to full shade
  • best performance occurs in moist, well-drained, rich soils with a cool root zone in partial shade, but it is highly adaptable to average to poor soils, soils of various pH, drought, and heat (as long as the heat and drought occur in a shady location)
  • propagated primarily by rooted stem cuttings
  • Box Family, with a variety of physiological, pest, and disease problems, most of which are minor and either do not occur, or have minimal ornamental impact (such as leaf rolling with Boxwood Pysllid)
  • abundantly available in container, ball and burlap, or field pot form (although often sold out in mid-season)
  • site in a somewhat protected shady location for best year-round performance (mulch to protect the shallow roots from Winter freeze/thaw cycles and Summer drought, and site away from an open area that is exposed to Winter wind and sun, due to Boxwood being a broadleaf evergreen that is sometimes subject to winterburn and stem dieback)
  • responds very well to periodic shearing for very formal situations

• Foliage
  • ranging from medium green to dark green, evergreen, opposite, elliptical, and from 0.5" to 1" long, depending upon species, hybrid, and cultivar
  • short petioles lead to a grooved midrib
  • foliage on some forms may turn a drab olive or yellowish-brown in Winter and be rather unattractive

• Flowers
  • cream-colored inflorescences in late April and early May occur primarily on established shrubs, being noticeable but not showy
  • somewhat malodorous or pungently fragrant (depending upon personal perception) and attracting many bees

• Fruits
  • ornamentally insignificant black seeds occur within brown capsules and are often not seen

• Twigs
  • green, thin, four-sided, and eventually turning light brown

• Trunk
  • usually not applicable; on larger specimens, several trunks are usually present, but foliage and stems usually cover them all the way to the ground

• ID Summary
  • ovate to elliptical, small, broadleaf evergreen foliage is dull shiny to glossy, in various shades of green and densely covering the many thin stems, with the shrub having an overall rounded to upright growth shape, but easily shearable into different shapes if so desired

• Function
  • formal or tightly informal shrub, usually reserved for shady conditions and commonly used as a hedge, foundation planting, edger, or facer shrub
  • can also be used for formal gardens, topiary gardens, or English gardens, as it responds very well to shearing

• Texture
  • very fine texture
  • very thick density

• Assets
  • grows very well in shady conditions
  • dense broadleaf evergreen foliage
  • can be sheared into a formal hedge, shrub, or topiary
  • usually maintains a dense, formal appearance even without pruning (low maintenance)

• Liabilities
  • very slow growth
  • relatively expensive
  • foliage may burn on some forms or species in severe Winters, especially at the stem tips
  • malodorous inflorescences occur on established, relatively unpruned specimens
  • some cultivars or species have unattractive brownish-yellow foliage in Winter

• Habitat
  • zones 5 (actually variable from 4 to 6, depending upon type) to 8
  • the various species are native to Korea, Japan, or the Mediterranean region; many modern cultivars are actually hybrid selections

• Alternates
  • small evergreen shrubs (Chamaecyparis obtusa 'Nana', Picea abies 'Pumila', Rhododendron yakusimanum 'Mist Maiden', Taxus x media 'Everlow' (if sheared), Thuja occidentalis 'Hetz Midget', Tsuga canadensis 'Gentsch White', etc.)
  • small deciduous flowering shrubs that tolerate shady conditions (Clethra alnifolia 'Hummingbird', Fothergilla gardenii, Itea virginica 'Henry's Garnet', Rhododendron 'Delaware Valley White', etc.)

• Variants
  • Buxus microphylla koreana - Littleleaf Boxwood or Korean Boxwood - grown for its hardiness from zone 4 through zone 9, but its miniature foliage usually turns a very unattractive, dead-looking yellow-brown in zones 4 to 6 Winters
    • Buxus microphylla koreana 'Winter Gem' - has the lightest green foliage color of all the Boxwoods, with new, relatively large foliage emerging lime-green on yellowish stems and maturing by mid-Summer to medium green, with minimal leaf margin burn in Winter; also the fastest growing of all the modern Boxwoods, and often needs to be sheared twice in a growing season if maintained in a formal shrub appearance or as a formal hedge; very popular in zones 4 and 5; 'Winter Gem' may actually be a selection of Buxus microphylla koreana 'Wintergreen'
  • Buxus sempervirens - glossy, larger, dark green Winter foliage is popular in Southern regions with many cultivars, but usually only cold hardy from zones 6 to 8
    • Buxus sempervirens 'Vardar Valley' - the standard cold-hardy cultivar for this species, which matures at 3' tall by 5' wide and is hardy through zone 5, very popular
  • Buxus microphylla koreana x Buxus sempervirens - the "Green Series" consists of Canadian hybrids developed in Southern Ontario of these two species, useful from zones 5 to 8:
    • Buxus 'Green Gem' - 2' tall by 2' wide
    • Buxus 'Green Mound' - 3' tall by 3' wide
    • Buxus 'Green Mountain' - 5' tall by 3' wide, naturally pyramidal, an alternative evergreen to replace the overused Dwarf Alberta Spruce (Picea glauca 'Conica'), which is very prone to disease and pest problems with age
    • Buxus 'Green Velvet' - 3' tall by 3' wide, very popular in zone 5

• Translation
  • Buxus is the Latin name for Boxwood.
  • microphylla translates as "little leaf".
  • koreana translates as "from Korea".
  • sempervirens translates as "always green".

• Purpose
  • Boxwood, with its many forms, is an exquisite, slow-growing, fine-textured, dense evergreen shrub or hedge for shady areas, moderately expensive for its size due to its slow growth rate (and therefore relatively long time period to reach saleable sizes).

• Summary
  • Buxus is perhaps the best of the broadleaf evergreen small formal shrubs, available in several forms and excellent when properly used in shady conditions as a specimen, edging, or hedge shrub.