The genus Euphorbia is one of the largest and most astonishingly varied of all the plant genera. It contains over 2,000 species, ranging in form and habit from diminutive groundcovers to enormous 70-foot-tall trees. Picture a leafy holiday poinsettia (Euphorbia pulcherrima) beside another very common houseplant, the prickly, succulent crown-of-thorns (Euphorbia milii), and you get an idea of the diversity.
Euphobia characias ssp. wulfenii
A member of the Euphorbiaceae, or spurge family, Euphorbia is distributed worldwide but found mainly in Europe, Africa, and Asia. Euphorbia species (often just called spurges) are adapted to many different climates and habitats. South African species, for example, are the "cacti" of the Old World, having evolved—independently but under dry, desert conditions—succulent spine-covered stems that greatly resemble those of North American cacti.
Because of the many options it offers, Euphorbia is a "must have" genus for every gardener. The narrow leaves that cloak the stems of many species are tinted gray-green, blue-green, red, or even pink. You can choose from numerous shapes—rounded hummocks for the front of a border, columnar specimens for focal points, and trailing forms for draping gracefully over rocks, banks, or walls. Several species offer evergreen leaves for year-round interest. The true flowers of spurges are small, but most are surrounded by brilliant yellow bracts that illuminate the garden for weeks. A few have red or orange bracts and stems.
Following are some of my favorite Euphorbia species and cultivars.
Evergreen Species
Two feet tall and wide, Euphorbia rigida (Zones 7 to 10) has erect stems that lean a bit sideways as the plant matures. The sharply pointed blue-gray leaves shimmer with light and create a beautiful pattern, like a living sculpture. Bright yellow flower heads top the stems in early spring.
Even more architectural, Euphorbia characias ssp. wulfenii (Zones 7 to 10) rises three feet tall and spreads about as wide. Its strongly upright stems and narrow blue-green leaves are beautiful enough, but they become even more striking when topped with a column of yellow bracts in springtime. This spurge will tolerate shade, even the dry shade beneath deciduous trees.
To illuminate dark places, plant 'Lambrook Gold,' a cultivar originally from Margery Fish's English garden; it has narrower, more silvery leaves than the straight species and stockier, brighter yellow flower heads. Or try 'Ember Queen,' with its white edges outlining the foliage.
Shapely Euphorbia x martini (Zones 7 to 10) forms an attractive rounded shrub about three feet tall and wide. Stems are covered with bronze-tinted gray-green leaves, which deepen to red in fall and winter. The chartreuse flower heads are surrounded by showy bracts marked with dark eyes. 'Red Martin' and 'Cherokee' are similar, red-tinted cultivars. 'Jade Dragon' is one of my favorites, with hints of purple in the foliage and new floral growth that's plated like dragon scales.
Mrs. Robb's wood spurge, Euphorbia amygdaloides var. robbiae (Zones 6 to 9), can be considered a thug or a blessing, depending on its use. Dark green, lustrous rosettes on foot-tall stems spread quickly by stolons to form an evergreen carpet. In spring, columns of brilliant yellow bracts top the leaves. This plant is best placed in dry shade where little else will survive, and even there it must be thinned every few years to be kept in check.
Perfect for sunny rock gardens, banks, or along a driveway, donkeytail spurge, Euphorbia myrsinites (Zones 5 to 8), has long trailing stems covered with blue-green leaves that look like miniature eucalyptus branches. Bright yellow flowers bloom at the tips of the stems as early as February. The plant is only about six inches tall but spreads a foot or more in width. (A note of caution, however: Euphorbia myrsinites is listed by the USDA as a noxious weed in the state of Colorado.)
Pink, Red, and Orange Tints
Most brilliant of the spurges, Euphorbia griffithii (Zones 4 to 9), flaunts pink and orange tints in its new leaves, which are lance-shaped with red midribs. Orange-red flower bracts top the three-foot-tall stems in late spring and early summer like fireworks, setting the stage for warm-toned color schemes. This spurge tolerates heavy clay soil and grows well in full sun or part shade. The cultivar 'Fireglow' is an even more vivid bright red-orange; 'Fire Charm' and 'Dixter' are shorter and more orange.
Like stained glass, the new growth on Euphorbia sikkimensis (Zones 6 to 9) is suffused with bright pink-red as it surges forth in the spring garden. That would be enough color for me, but in midsummer, yellow flowers top the stems for a final flourish. This spurge travels by runners at a moderate pace and is easy enough to keep at bay by removing outlying patches.
Companionable Combinations
Donkeytail spurge (Euphorbia myrsinites) combines well with 'Plum Pudding' coral bells (Heuchera 'Plum Pudding'), the burgundy and maple-shaped leaves of the coral bell providing contrast for the spurge's blue-green, succulent leaves. Add some early low-growing daffodils like 'Tête-à-Tête,' purple dwarf bearded irises for a riveting contrast, Dianthus barbatus 'Sooty' with maroon spring flowers, and Sedum spectabile 'Carmen' with pink fall flower domes, and you've covered all the seasons.
I love Euphorbia characias ssp. wulfenii paired with 'Arp' rosemary in hot sun—both hold their leaves year-round, and the rosemary's fine needles contrast well with the spurge's long, lancelike leaves. Occasionally they bloom together—the rosemary's blue flowers a perfect complement to the spurge's yellow bracts. In shady sites, winter-blooming Lenten rose (Helleborus orientalis), another evergreen, is a great partner for spurge, offering lobed leaves for contrast, and shorter stature. 'Bowles Golden' sedge (Carex elata 'Bowles Golden') makes a fine color complement to the spurge's flowers. Any of the blue-green hostas would anchor the picture in shade.
Orange-flowering Euphorbia griffithii marries beautifully with yellow and orange early Asiatic lilies (Lilium), yellow- flowering Lysimachia ciliata, and orange Geum 'Borisii.' Add splashes of blue-violet Geranium pratense or G. ibericum to electrify the orange tints even more.
The pink and red tints of Euphorbia sikkimensis can be showcased by planting contrasting companions, such as blue oat grass (Helictotrichon sempervirens), or by allowing the plant to emerge from a surrounding filigree of green ferns. Peruvian lilies (Alstroemeria hybrids), which bloom in shades of pink and orange, and pink and orange Asiatic lilies, can be added for color echoes.
Culture and Propagation
Most spurges thrive in full sun as well as partial shade and grow happily in fertile, well-drained garden soil. To improve drainage in heavy clay soils, amend with generous amounts of finely crushed gravel or pumice. If your soil is especially heavy and wet, plant the marsh spurge, Euphorbia palustris (Zones 5 to 8), which forms showy colonies of gray-green leaves topped by columns of dazzling yellow flowers that bloom for weeks in early spring.
A few spurges are prone to powdery mildew and should be avoided if your climate is rainy or damp. The once popular Euphorbia dulcis 'Chameleon' has lost its charm in the Pacific Northwest due to pervasive mildew, and the same is true for E. amygdaloides 'Rubra'. The early wine tones in the leaves of both these plants don't compensate for the diseases that follow. I also urge you to avoid Euphorbia cyparissias, as it creeps and invades without bounds. (Indeed, as with E. myrsinites, this plant is on Colorado's noxious weed list.)
One more note of caution. Spurge stems, when cut or bruised, exude a milky sap that can be irritating to skin and especially to the eyes. So when you're pruning or deadheading, protect your hands with rubber gloves, and either wear goggles or be careful not to get spurge juice anywhere near your eyes.
Most spurges can be propagated from root cuttings, which should be placed in water for a while to drain off the milky sap (otherwise, the latex may seal the stem and make rooting down difficult). Even simpler, lift and divide the mother plant into sections and replant each division. Many spurges will self-sow without encouragement, sometimes excessively—you will hear tiny popping sounds as the seedpods explode. To prevent this, cut the spent flower stems to the ground before seeds ripen. Deadheading is a good practice before or after the seeds form, as the bracts turn a shabby tan, then brown, by mid- to late summer, detracting from the handsome leaves. Once groomed, the plants take on a renewed beauty.
Nursery Sources:
Canyon Creek Nursery3527 Dry Creek Road
Oroville, CA 95965
530-533-2166
www.canyoncreeknursery.com Digging Dog Nursery
P.O. Box 471
Albion, CA 95410
707-937-1130
www.diggingdog.com Forestfarm
990 Tetherow Road
Williams, OR 97544-9599
541-846-7269
www.forestfarm.com Greer Gardens
1280 Goodpasture Island Road
Eugene, OR 97401-1794
800-548-0111
www.greergardens.com Niche Gardens
1111 Dawson Road
Chapel Hill, NC 27516
919-967-0078
www.nichegardens.com
