Buxus sempervirens L. –Common boxwood, box
FAMILY: Buxaceae—the Box Family
This family contains two genera of plants used for ornamental purposes, Buxus and Pachysandra. The former is an evergreen shrub widely used in horticulture, while the latter is an evergreen ground cover, equally common in use. Characteristics for the family are: flowers: unisexual, regular, inconspicuous; sepals: 4, basally fused; stamens: 4, opposite the calyx lobes; pistil: 1; ovary: superior.
PHENOLOGY: Boxwood flowers in spring.
DISTRIBUTION: Cultivated as a hedge, foundation, specimen, or edging (dwarf) plant.
PLANT CHARACTERISTICS: Leaves: elliptic to lanceolate-oblong, broadest below the middle, dark green and lustrous above; flowers: in axillary clusters, with a terminal female flower and several male flowers below in the axils of bracteoles; petals: absent; female flowers: with a 3celled ovary; fruit: a capsule with 3, two-horned valves.
POISONOUS PARTS: The leaves and stems are poisonous. Toxicity to horses is estimated to be 0.15% (green-weight basis) of body weight, which for an average animal is equivalent to 1.5 lbs. of leaves.
SYMPTOMS: Severe gastroenteritis, vomiting, bloody diarrhea, stomach pains, convulsion, and death through respiratory failure may result from ingestion of boxwood.
POISONOUS PRINCIPLES: The akaloid buxene (buxine) has been implicated in poisonings. Other active principles are probably involved, including a volatile oil.
CONFUSED TAXA: No other cultivated plants have simple, opposite, oval, leathery leaves. Some varieties of holly (Ilex) or cotoneaster (Cotoneaster) may be confused with box, but these have alternate, not opposite, leaves.
SPECIES OF ANIMALS AFFECTED: Horses, sheep, pigs, and cattle have been poisoned.
TREATMENT: (11a)(b); (26)