EUPHORBIA. Spurge. Nearly worldwide. A vast group ranging in plant type from annuals to trees. Many have milky—usually poisonous—juice. The flower clusters are often showy, but what appear to be the flowers are usually the bracts below them (the actual blossoms are without petals and usually not obvious). It is impossible to make many other generalizations about a group so large. However, the following few are hardy and easily grown, delighting in sun and reasonably well drained soil. Wear gloves and a long-sleeved shirt when handling them, and don’t plant them where children play! The juice of species like E. characias and E. myrsinites nearly leaps out of cut stems and can raise blisters and damage the eyes.
amygdaloides. Wood spurge. Europe and western Asia. This is a perennial with clustered, erect stems from a narrow base. It can grow over 2’ high, though the cultivated forms are usually smaller. Deep green leaves up to 4" long are loosely set around the stems. The flower clusters are open and rise well above the foliage, showing bright lime-green “flower leaves”. ‘Purpurea’ is a relatively short, dense form with reddish stems, beautifully purple-tinged leaves and some purple shading in the flower clusters. The flowering season extends from mid-spring into summer, at least along the coast. This is a fine border perennial, though sometimes widely spreading. Hardy to 10oF. or less.
characias. One of the true spectacles of the group, though it is definitely not for everyone. The plants are nearly shrubby, sending up several thick, leafy stems, 2-5’ high, from a woody base. The leaves are up to 4" long, rather narrow and colored an unusual blue- or grey-green. In late winter and early spring the flower clusters unfold at the tips of second-year stems, becoming broad towers as much as a foot long. The floral leaves and bracts are painted brilliant chartreuse to yellow and hold their color well for several weeks after the flowers have gone. The little flowers themselves are bright green, making a pleasant contrast. The subspecies wulfenii is even larger, in all its parts. The cultivar ‘Portuguese Velvet’, evidently from the type species, is considerably smaller and distinguished by darker, greener leaves with a strikingly velvety surface. It also has the odd habit of producing small plantlets at the ends of the flower stems, providing an easy means of propagation. Both are hardy to 0-10oF.
cyparissias. Cypress spurge. Europe. If I were forced to declare a favorite among the genus, this would be it. Cypress spurge travels slowly in all directions by rhizomes and makes broad, billowy mounds up to a foot (or slightly more) high. The slender stems are well branched and lined by brushes of very narrow 1-2" leaves, giving a delicate appearance. The leaves are bright to light green or blue-green in color. For several weeks in late spring and summer it is nearly covered by umbrella-shaped flower clusters showing bright greenish yellow bracts. ‘Fen’s Ruby’ is a particularly short, dense selection with blue-green leaves, strongly tinged with purple in new growth. All forms are winter-deciduous in colder climates. These are delightful plants for borders, ground cover and open banks, in sun or light shade. While it performs best with moderate watering, it is fairly drought tolerant. You will probably have to rogue out some volunteer shoots and seedlings in unwanted places. Hardy to below 0oF.
robbiae. A species also known as E. amygdaloides var. robbiae (or ‘Robbiae’). This is a rhizomatous perennial, making thick colonies. The individual stems are erect, 1’ to nearly 3’ high (probably closer to 1’ in our current form) and have broad, whorled leaves. The leaves are thick and leathery, deep green and shiny above, paler beneath. The flower clusters are rather open, with light green leaves and bracts.This is a fine plant for borders or small-scale ground cover. It is shade tolerant and hardy to 10oF. or less.