By Barb Triol, Sonoma County Master Gardener
As I roam my front yard during the months of March and April, I see that many of the plants are still tucked away for the winter, waiting for a bit more sunshine and warmer temperatures. However, along with the bulbs that are filling the garden with color, I notice one of my favorite plant groups displaying its striking foliage and beautiful chartreuse bracts – the various species and varieties of Euphorbia.
Euphorbia come in all shapes and sizes. They can be annuals, perennials, evergreen or deciduous and even shrubs or trees. Euphorbia is a very large genus with over 2,000 species and is a part of the Euphorbiaceae family. Euphorbia originated mostly in Africa, the Americas and Madagascar and do quite well in temperate zones worldwide including the Mediterranean climate we have here in Sonoma County. If you don’t think you have ever seen a Euphorbia, think again. The common holiday plant, Poinsettia, is a Euphorbia! It looks a bit different than most of its fellow species grown in local gardens, but it is definitely a Euphorbia (E. pulcherrima).
Euphorbias are long-lived, relatively easy-care perennials that are either evergreen or die down to the ground in winter and come back in the spring. Their leafy-stemmed foliage comes in many colors, sizes and textures. The plants are many different shapes: mounds, upright stem sets or low ground crawlers, to name a few. Euphorbias tend to flower from early spring to early summer and then continue to provide beautiful foliage throughout the growing season or even year round. Many are drought tolerant and deer and gopher resistant. All of this makes them a great addition to any Sonoma County garden.
One of the more unusual aspects of Euphorbia is how it “flowers”. What is mistakenly called a “flower” is technically a cyathium, consisting of fused bracts that form a cup around a very small true flower. The bunches of leaf-like bracts grow on the end of the leafy stems and are frequently brightly colored; many species are a chartreuse color that reflects light and makes for a stunning display in your garden. The leafy stems are also attractive – varying from blue, blue-green, reddish-green, reddish-orange and green tinged with purple.
The planting requirements of Euphorbia vary depending on the species. Many require full sun, but some species can tolerate partial shade and a few can even handle full shade. Most of the species that thrive in Sonoma County like the heat but can also take some frost. They can be drought resistant, but some need regular water and almost all dislike soggy feet. As you can see, the needs of Euphorbia can vary widely, so make sure you read the label, ask your nursery experts and/or look up the particular species in one of your trusty garden books to get the particular needs of that specific plant.
There are many redeeming features of Euphorbia, but they do come with some drawbacks. All Euphorbia have a milky white sap in their stems that is irritating on contact, can be toxic if ingested and especially painful if it gets into your eyes. It’s important to use care when cutting them and wash up quickly after pruning. Gloves and long sleeves help protect your hands and arms. The good news is that the unappetizing sap keeps the deer and gophers away! Euphorbia is a best seller on the deer resistant plant list and that is a big bonus if you live in many parts of the County. It also multiplies in the garden, spreading by seed or underground stems. For some species this can be a bit annoying, but for most they are easily pulled up and worth the trouble.
Below is a sampling of Euphorbia varieties that grow well in Sonoma County and are readily available:
Euphorbia amygdaloides robbiae – Commonly called Mrs. Robb’s Bonnet, this is a useful variety because it is shorter (to 1 ft tall) and can tolerate more shade than most Euphorbia. It spreads via rhizomes but is containable.
Euphorbia martinii – A hybrid of E.characias and E.amygdaloides, it’s smaller - 2-3 feet - and has dark green leaves tinged with a bit of purple. It sports dense clusters of chartreuse flowers with dark centers and is a real treat this time of the year. It likes full sun/part shade, is drought resistant and does not reseed as much as others.
Euphorbia myrsinites – This is the laid-back Euphorbia that you will see in Sonoma County gardens. It is evergreen and has stems that trail on the ground outward from the crown. Blue-green leaves around the stems end in clusters of chartreuse bracts in the early spring. Cut back the flowers as you do with other Euphorbia
These are just a few species and varieties. There are many more that do well in Sonoma County. I have found Euphorbia to be relatively trouble free and an interesting plant to grow in my garden. They do require a bit of maintenance in the cutting back of the spent flower stems and keeping the spreading at bay. But all-in-all, a plant worthy of being one of the Top Plants for Sonoma County and April’s Plant of the Month.
Euphorbias can be purchased locally at many nurseries in the county. Emerisa in Santa Rosa has a good variety now and more coming in the next month. Cottage Gardens in Petaluma also carries many varieties throughout the year, as does Sonoma Mission Gardens in Sonoma.
©Sonoma County Master Gardeners