Scientific: Buxus microphylla japonica
Common: Japanese boxwood
Family: Buxaceae
Origin: China, Japan

Pronounciation: BUX-sus my-cro-FII-la ja-PA-nee-ca

Hardiness zones:
Sunset 8-24
USDA 6 (in protected locations)-11

Landscape Use: Edging, barrier, small-scale formal or informal hedge, entryway, foundation plant, mesic landscape design themes, container plant, bonsai.

Form & Character: Formal, dense canopy, upright....did I say "formal".

Growth Habit: Evergreen, woody perennial shrub, slow to moderate growth habit eventually reaching to 4 to 6 feet height with somewhat less spread, can be kept much smaller as a clipped shrub.

Foliage/texture: Leaves small, greenish to 1 inch long or less, prominent mid-vein, no trichomes on mid-vein like Buxus microphylla koreana, young stems green too, foliage turns a bronze color during winter in colder climates; medium fine texture.

Flowers & fruits: Greenish flower in axillary meristems, spring, flowers and fruits are inconspicuous.

Seasonal color: None in Phoenix, though in colder climates the foliage will develop a brown to purple tinge in winter.

Temperature: Hardy to 0oF, but struggles to survive the in the lower desert because of the summer heat.

Light: Partial to full shade is, northern and eastern exposures are required. In Phoenix, avoid full western exposures at all costs!

Soil: Surprisingly tolerant of alkaline soil, though does best in chemically neutral to acidic soil.

Watering: Regular

Pruning: Here it is landscape neat freaks!!! FINALLY a shrub that you can shear with wild abandon and not be called a horticultural clod for having done so. This is your plant!
All jesting aside (not really), this shrub should be regularly sheared for best results. It can be formally clipped into hedge as low as 2 to 3 feet or trained as a small topiary.

Propagation: Softwood cuttings rooted under mist in late spring and early summer.

Disease and pests: Spider mites and leaf miners

Additional comments: This is a plant that is 'out of step' with current regional demands to conserve water resources by installing landscape gardens with 'desert-adapted' plants. However, Japanese boxwood is a good western substitute for English boxwood (Buxus sempervirens) when landscape gardeners desire to create a formal landscape appearance with structural lines derived from the use of relatively diminutive hedging plants.

There are several superior cultivars of Japanese boxwood including 'Compacta', 'Green Beauty', and 'Winter Gem'. Another closely related subspecies, Buxus microphylla koreana (Korean boxwood), is in my opinion a more elegant and cold tolerant boxwood species for use in the western United States than Japanese boxwood. While Japanese boxwood performs well in Arizona's lower elevation cities, Korean boxwood is best used in the landscapes of Arizona's higher elevation cities such as Flagstaff, Payson, Prescott, Pinetop and Show Low.