Euphorbia characias subsp. wulfenii honors Austrian naturalist Franz Xavier von Wulfen, and the subspecies itself honors the distinction with slightly more of everything that makes the species worth growing: leaves a little larger, flowers a more emphatic yellow, and nectar glands in a striking dark purple. The chartreuse-yellow flower clusters that push up through the blue-green whorled foliage in spring have an almost unreal quality, catching light in a way that makes them visible from across the garden. At 2 to 3 feet, it runs a bit shorter than the typical species.

This plant is most at home in Mediterranean-type conditions — full sun, dry to medium soils, excellent drainage, and a tolerance for poor ground. Clay soils and the hot, humid summers of the American Southeast are its main vulnerabilities. In those climates, raised beds, rock gardens, or spots with good air circulation offer the best chance of success. After flowering, cutting stems back to the base encourages fresh growth and a tidier habit. It self-seeds readily, which can be an advantage in the right setting. All parts carry the toxic latex characteristic of the genus; protective gloves are essential when pruning or handling.