Carolyn Singer: Euphorbias have beauty and a ‘bite’: From holiday color to landscape choices | TheUnion.com

Carolyn Singer: Euphorbias have beauty and a ‘bite’: From holiday color to landscape choices

Carolyn Singer
Columnist

A dear friend brought me a cheerful Poinsettia this past week. Its intense red bracts are now decorating my kitchen. This quintessential holiday plant reminds me of being on Oahu, where to my amazement, machetes were being used to control the rampant Poinsettia hedges.

Poinsettias are in the genus Euphorbia (spurge), a group of plants known for their landscape value, and also for the milky fluid in the stems and leaves that may cause severe irritation. It's wise to use gloves when handling any of these.

Most, but not all, are deer-resistant. I will not be placing my gift Poinsettia outside during the day to test it.

Many Euphorbias are evergreen, making them dominant in the winter garden. Some are spreading groundcovers, others are tidy small plants. Still others grow to be very large shrubs. The variation is interesting.

Deer resistant plants

Usually available in local nurseries, one of my favorites of the deer-resistant species is the most invasive unless restrained. Its common name, Mrs. Robb's bonnet, has little to do with its growth habit. While I think of a bonnet as a charming head covering for an infant, the spurge called Mrs. Robb's bonnet (Euphorbia amygdaloides ssp. robbiae) spreads rambunctiously when given the space.

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Control its invasive growth habit by using it where hardscape holds it back. Even narrow strips often left by builders between a house and a walkway will work for this undemanding perennial. Glossy dark green leaves in tight rosettes are a striking evergreen groundcover about a foot in height. In bloom, three foot stalks open with showy chartreuse flowers. These later turn a soft brown. No "deadheading" (removal of faded blooms) is needed until winter storms bend the stalks.

Because it will grow in sun or shade, Mrs. Robb's bonnet is an effective groundcover under a deciduous tree even if shallow tree roots are competitive for nutrients and moisture.

Leaves falling in autumn will fall through the plant, adding valuable mulch each year. Shade in summer, with sun in winter is a perfect exposure. Very little irrigation is needed even in the hot summer months as long as this evergreen is in shade.

Winter gardens

Through my experimenting I have discovered that many lovely spurges are beautiful in winter. Even during the leaner months when deer seem to ravage many plants, most Euphorbias have not even been sampled.

Remember that the use of nitrogen fertilizers by growers may make leaves more tasty for the deer. Protect newly planted purchases until growth begins.

From the strongest groundcover to the tidiest accent plant, it's difficult to believe that these plants are so closely related, when Euphorbia "Tiny Tim" adds its charm to garden detail. Also evergreen with the same intriguing flowers, this species is very restrained at about eighteen inches in spread and under a foot in height. Perfect for an irrigated rock garden. "Tiny Tim" does well when it receives irrigation every week to ten days.

Larger evergreen spurges are not invasive, although their seeds may increase the planting if space is available. Unwanted volunteer seedlings are easy to dig and share, or toss on the compost pile.

I once spotted a local landscape where the very large (four feet in spread and height) blue green Euphorbia chariacas was the entire front garden. I wondered if the owners had allowed dozens to grow because they were deer-resistant.

The variation in the colors of foliage is remarkable. "Helen's Blush" is an evergreen with beautiful pink and rose leaves. An accent of evergreen "Silver Swan" brightens a semi-shady flower bed with its white and silvery-gray leaves.

Both of these variegated cultivars should not be in full hot summer sun. Nor will they tolerate the dry shade in which Mrs. Robb's bonnet thrives. Morning sun is perfect to optimize the leaf colors. Both are excellent subshrubs at two to three feet in height and spread.

Of course I am drawn to the spurges because the deer are not. Perhaps I could conclude that the milky sap is a deterrent, but I know better since one of my favorites spurges, Euphorbia amygdaloides "Purpurea" has been eaten by the deer each time I have tried it in my garden.

Perhaps the lovely purple-red foliage is, to them, much like the red lettuces I particularly like for my own greens.

Carolyn Singer has gardened organically in Nevada County since 1977. She is the author of the award-winning "The Seasoned Gardener, 5 decades of sustainable and practical garden wisdom," and two volumes of "Deer in My Garden" (deer-resistant plants), available locally. Send your gardening questions and comments to carolynfsinger@gmail.com. Check out her website at carolynsingergardens.com.

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