The popular Christmas poinsettia (Euphorbia pulcherrima) is just one of the 2,000 or so species of spurges. The genus includes many other houseplants, a few nasty weeds and some hardy gems suitable for perennial gardens or mixed borders. Hardy spurges vary widely in appearance, from low rock garden or edging plants to tall, bushy, almost shrub-sized specimens. A few are happiest only in mild-winter regions such as the West Coast.
As with the poinsettia, the showy parts of the spurge are actually modified leaves called bracts, which are usually bright and colourful. The actual flowers are the little round nibs held within the bracts, which sometimes form a distinctive eye.
All spurges share an easily recognizable trait—a milky white sap that appears when a leaf or stem is broken. The sap from all species except the poinsettia can cause skin reactions, so always wear gloves and long-sleeved clothing when handling these plants.
The most common of the hardy species, whose colours range from acid green to bright yellow, orange and scarlet, is cushion- or chrome-spurge (E. polychroma), which bursts from the ground in early spring, quickly forming a beautiful low, dome-shaped mound of light green leaves, topped by glowing chrome—yellow bracts that appear in late spring. After blooming, the plant benefits from a hard shearing to about 10 centimetres to rejuvenate the leaves and maintain its bushy, compact form for the remainder of the season.
'Bonfire' is a new selection of cushion spurge that keeps its deep maroon-red foliage all season. The white-edged leaves of 'First Blush' show pink highlights in the spring. These cultivars are reliably hardy to Zone 2, as are all cushion spurges.
Griffith's spurge is a mid-size species with a tendency to spread by underground roots. 'Fireglow' and 'Dixter' are the two most commonly available cultivars. 'Fireglow' grows to 90 centimetres, while 'Dixter' is slightly shorter at 70 centimetres. Both bloom in early summer and may continue to flower sporadically throughout the season. They do well in Zones 6 and up, but are worth a try in colder regions where snow cover is reliable all winter. 'Jessie' is an exciting new hybrid of 'Fireglow' and cushion spurge that forms a substantial clump suitable for the middle or back of borders. Its bright yellow bracts are edged in orange-red and stay attractive for six weeks or more.