Its stiff, steel-blue foliage is a broad clue that Euphorbia rigida, commonly called silver spurge, comes from the Mediterranean. Like its more familiar cousin, the prostrate creeping spurge (Euphorbia myrsinites), it is a low-growing variety with small leaves. Both are sometimes called donkey tail because of their long, thin stems, or gopher plant because they are believed to repel burrowing pests. Silver spurge is an attractive, easy-care, succulent perennial and grows in U.S. Department of Agriculture plant hardiness zones 7 through 11.
Silver spurge is small, reaching 1 to 2 feet tall and spreading 3 feet wide. Its leaves, which are sharply pointed at the tips, are evergreen, but exposure to cold and wind sometimes cause it to drop its leaves. The leaves are arranged in spirals around the plant’s upright stems. In fall, they take on a bronze tint. Silver spurge doesn’t have a deep root system, making it a good choice for rock garden nooks and low-water gardens.
The flowers of silver spurge are yellow and bloom in clusters at the tips of the stems. They appear from late spring into early summer and then age to a pale orange. While the seed heads are attractive, you may want to remove the flowers before they mature, so the plant doesn’t self-seed. The blooms have no fragrance but are attractive to bees.
Plant silver spurge in a protected spot in full to part sun and in soil that drains quickly. It’s not fussy about soil type and doesn’t need rich soil or fertilizer. It is drought-tolerant, so when you water it, soak it well and then let the soil dry completely before watering it again. While deer tend to leave it alone, pests, such as aphids, mealybugs and spider mites, attack silver spurge. Watch for them and wash them off with a strong stream of water from the hose at the first sign.
Silver spurge should be cut back to the ground in late fall for fresh growth in spring. But, like all euphorbias, it bleeds a milky sap when cut. The sap is an eye and skin irritant, so wear gloves when pruning or weeding around the plant. Flush the eyes with water if sap gets into them and seek medical advice. If eaten, the sap causes nausea.
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