It's also one of the hardy ones, rated from USDA zone 3 to 9. I think mine was simply in the wrong spot - and one of the best all around border plants. I keep forgetting to get it until it's too late. The flowers are much more complex than most euphorbs, appearing double and frilly in the center. Euphorbia griffithi 'Fireglow' is another that I once grew for several years, until I stupidly let it get shaded out while my back was turned.
Stems are an orange-brown while the light olive green foliage has red veins.
But most colorful are the flowers, a vibrant coral-red, enhanced by the same red staining of the leaflets just below the flower head. Bloom time is from early to late summer. Native to the Himalayas, it's rated hardy to USDA zone 6 and prefers a rich retentive soil with as much sun as you can give it. Mine did quite well with about three or four hours of direct sun, but when the surrounding shrubs and trees matured to shade it all the time, it simply faded away. It has a cousin that looks, if anything, even more interesting.