Too few perennials continue to create a great display from spring until late fall. But euphorbia is on the scene, front and center, and continues to be a true star in spring, summer and fall. In fact, just like fine wine, it gets better as it ages.
This underused plant is commonly known as spurge, a name derived from the French verb espurgier, meaning to purge. It was ancient custom to utilize the plant's sap as a laxative or purgative. The botanical name was given in honor of the Greek physician Euphorbus, who perhaps treated his patients with a dose of the sap to cure their discomfort. All of this information cannot detract from the sheer beauty and impact of this perennial.
Euphorbias are related to poinsettias. In both cases, what look like flowers are not true blooms but bracts on top of the foliage, a form of modified leaves. These showy blossoms float above the stems in late spring, then fade as the weather grows warmer. But as the bracts fade, the foliage continues the show by creating a magnificent mound of color that intensifies as the seasons progress.
The different cultivars within the species are so diverse in appearance that you can utilize many throughout the garden. These shrubby mounds will light up the landscape either in full sun or partial shade, maturing to 1-2 feet in height and width and complementing other plants within the garden beds. The diverse colorations make choice difficult, so I feature several euphorbias throughout the landscape. There are no personal favorites. They are all insanely beautiful. Because they are native to the Mediterranean, they even hold up well under hot, dry conditions.
'Bonfire' is true to its name. As the heat of the summer intensifies, it glows even brighter. The leaves first emerge green, then change to red topped by bright yellow "floral" tips. Even after the flowers are gone, the flaming red foliage continues to smolder into the cool fall days of fall. This one screams for attention.
'Blackbird' is darker and a bit taller. The leaves are a deep, rich purple and become more intensely colored in sunlight. Just like its namesake, a bird that displays breathtaking color on its wings, this plant is topped by glowing yellow bracts that make the darkened leaves seem to vibrate. The total effect is stunning.
In spring, 'Polychroma' is topped by a tight-knit mass of sunny yellow bracts supported by a light green foliage. The flowers are so profuse that the foliage is totally overwhelmed until they wither. It is shorter, 12-18 inches high and wide, and is a perfect companion plant for spring bulbs. It is an absolute star in the rock garden. It can be wedged in comfortably and still put on a great show.
'Tasmanian Tiger' is tall, reaching 3 feet at maturity. It is unique in that the leaves are variegated stripes, white edged by a lighter green. It stands tall and strong without support and is topped by pale yellow and cream-colored bracts. It prefers partial shade to maintain the variegation without burning the foliage.
All euphorbias do well in sun to part shade. Well-drained soil is a necessity for success. After the flowers have faded, shear them off and prune for shape, which allows the plant to grow into a well-rounded mound. Keep in mind that the stems do produce a milky sap, which can cause skin irritation, so garden gloves are imperative when working on this plant. Disposable gloves work best. My 'Bonfire' grew so large that one of our torrential summer rains caused it to splay. Knowing that it would never again become a compact mound, I pruned, dug and divided it. This was done with much trepidation because the species does not like to be transplanted and division should be considered an option only every five years. I was rewarded with new growth, and I'm happy to report that the transplants are doing well.
These plants can retain their foliage during the winter and then be pruned back by a third in early spring. This is the time when nurseries are marking down their stock that failed to go to a good home in season. Consider adopting one or more varieties of euphorbia. They will happily brighten your garden from spring through fall and best of all, they are deer and rabbit resistant.
Plumline Nursery, 724-327-6775, 4151 Logan Ferry Road, Murrysville.
The Urban Gardener, 412-323-4769, 1901 Brighton Road, North Side.
Bluestone Perennials, www.bluestoneperennials.com, 1-800-852-5243.
Susan Silverman, a master gardener from Murrysville, was a co-winner, large garden category, of the 2006 Great Gardens contest.