Seed for this species is all or nothing. The straight species of Mediterranean spurge, Euphorbia characias, seeds abundantly. It can actually be a bit too prolific. However, fancier and extensively bred cultivars either produce no viable seed, or produce only a few seed that are not true to type. Such seed grows into plants that resemble their ancestral species more than their direct parents.
Foliage of common Mediterranean spurge is slightly grayish green. Cultivars exhibit more distinctly grayish, bluish, yellowish or variegated foliage. Appealingly weird and generally greenish floral trusses bloom on top of upwardly arching stems about now. Mature plants are less than four feet tall and broad, with neatly rounded form. They slowly lean toward sunlight as they grow and bloom.
After old stems get cut to the ground in autumn, new stems develop through winter, to repeat the process. Established plants are surprisingly resilient to harsh exposure, warmth, wind and lapses of irrigation. They just dislike shade and constant dampness. However, even the healthiest live for only five to eight years. Those that toss seed can provide their own replacements before they go.