Traditional in France, gardens with formal, clipped boxwood accents (shown here, Buxus microphylla ‘Wintergreen') are now fashionable in Canada. Used as a low hedge around a flower bed, flanking a pathway or shaped into an intricate knot garden, clipped boxwood can add a sophisticated je ne sais quois to the garden. Taller cultivars of this broadleaf evergreen (Buxus sempervirens) can be left unpruned to grow au naturel or be trained into handsome topiary specimens. A plant to be coveted, indeed.
Sadly, boxwood just says non! to living in much of Canada. This Zone 6 plant prefers cool, moist conditions where its shallow, fibrous roots are undisturbed. It abhors temperature extremes, scalding sun, drought or desiccating winds, all of which can turn its foliage dull and brown. This expensive prima donna is also prone to complaints such as boxwood psyllid, mites, leaf miner and phytophthora root rot (made worse by heavy clay soils). And it keels over quickly when faced with winter salt damage or the leg-lifting attentions of passing pooches.
Voila! Here is a list of sturdy, easy-going imposters that can be kept pruned in a passably boxwood-like manner.
Laurel Willow (Salix pentandra)
Height: 8 to 10 m
Spread: 5 m
Location: full sun
Cultivation: tolerant of city conditions
Foliage colour: dark green (summer), yellow (fall)
PJM Rhododendron (Rhododendron ‘PJM')
Height: 90 cm
Spread: 1.25 m
Location: full sun or partial shade
Cultivation: moist, acidic to neutral, well-drained organic soil. Protect in winter
Foliage colour: dark green (summer), mahogany/plum-purple (winter)
Flowers: lavender-pink, late May
Hill's Yew (Taxus media ‘Hillii')
Height: 150 cm
Spread: 125 cm
Location: full sun or full shade
Cultivation: well-drained, fertile soil
Foliage colour: dark green
Fruit: red aril covers seed.