When I think about it, my attracrtion to euphorbias (and they are my plant of the decade) makes sense in a few ways. I'm attracted to their eclectic, unusual look - their outer space 'flowers' (often chartreuse) are set against narrow, whorled, always interesting foliage. I'm excited by their diversity - at any given year there are lots of different varieties in the nursery trade and they come in quite a range of size and color; it makes the hunt for new plants particularly satisfying. Finally, and perhaps the best reason for all California gardeners, euphorbias are really easy to grow, tolerating wide ranges of light and low water conditions - with the added benefit of being extremely deer and gopher resistant!
You get the picture, I'm a lazy (or smart) gardener who likes lots of different 'weird' stuff.
Euphorbias (you-for-be-ahs) have a heck of a name to get around, but the plants are so great they have to have SOME sort of difficulty about them.The genus has been much maligned over the years; few of it's many species of plants can be invasive, and all euphorbias have a milky sap that may be irritating on contact or even toxic if ingested (degree of irritation or toxicity varies depending on species; most species in the nursery trade are fine). Hey, that's why they're so varmint resistant! A perceived problem for one gardener may be a solution in a yard with a deer problem. Some species may reseed, but the nursery trade varieties usually don't reseed enough to become a pest. In any case, these guys don't set down giant roots, it's pretty easy to pull out unwanted guest (or move them to another yard). Most of them will need the proverbial 'well drained soil', so don't include them in your bog garden; usually average garden soil is fine for most of these perennials.
Even our hallowed poinsttias are euphorbias. BUT (here we go with diversity), a different species of euphorbia will look totally different than the poinsetta, which will also look totally different than the houseplant known as Baseball plant (euphorbia obesa) which looks totally different than the many varieties of Euphorbia characias.
A sample of some nice garden euphorbias:
Euphorbia characias wulfenii: A 4' tall by 4' wide plant with chartreuse flowers. It is the workhorse of the genus, tolerating full sun to full shade (really!); drought resistant. wulfenii can reseed but is not invasive in our dry climate unless you add lots of water to its regimen. This one will tolerate dry full shade while ignoring heavy deer pressure, a miracle plant!
Euphorbia characias 'Humpty Dumpty': 2.5' tall by 2' wide, a dwarf wulfenii
Euphorbia characias 'Tasmanian Tiger': 2'x 2', handsome with leaves and flowers edged in cream, a nice variegated plant. Needs good drainage!
Euphorbia amygdaloides 'Purpurea': 3' x 3', leaves heavily tinted purple or burgundy, chartreuse spring flowers through early summer, a stunner in bloom, handsome most times of the year.
Euphorbia 'Helen's Blush': 2'x 2', foliage variegated with pink, cream, and light green; burgundy tints in winter; pinkish green flowers; good in containers.
Euphorbia 'Blue Haze': 12" x 24" , powder blue foliage, soft yellow flowers spring through summer, very drought tolerant. A beautiful blue plant.
Euphorbia myrsinites: 6"x 18", trainling plant with stiff roundish blue-gray leaves. Flattish yellow flowers late winter. Good rock garden plant, it looks like a succulent. It may seed prolifically with lots of water.
VERY drought resistant.
Euphorbia cyparissias 'Fen's Ruby': 8" tall feathery clump that spreads vigorously by rhizomes. It can be invasive, but I find it pretty easy to control , especially if you don't go overboard with the water. This one is a real cutie.
Euphorbia 'Raven': 20" x20", reddish black foliage and flowers make this a good plant for high contrast with lime green or cream plants and flowers.
All of these euphorbias look better if given a hard haircut in summer (yes summer). They have notably good looks in winter if this pruning is done.