April 2011 Plant of the Month —
Robb’s Spurge

An evergreen groundcover, Robb’s spurge (left) is one of the easiest and most dependable of all euphorbias to grow in Tennessee. In the shade garden, its yellow-green blooms pair well with the purple of woodland phlox (above right). Photos by J. Reeves.
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Submitted by Jason Reeves, curator of the UT Gardens - Jackson

Approximately 1500 species of euphorbia occur throughout the world. Some are mere weeds, while others are good garden plants. The poinsettia is the most common euphorbia in the US.

Most euphorbias prefer full sun, well drained soil and dislike humidity, therefore perform poorly in the south. One exception is Robb’s Spurge, Euphorbia amygdaloides var. robbiae.

Robb’s spurge is one of the easiest and most dependable of all euphorbias to grow in Tennessee. Unlike most of its temperamental cousins, once established it will be with you for a lifetime.

The spoon shaped, dark green, glossy leathery leaves are arranged in tight rosettes on the stems. In early spring, yellow-green bracts and flowers appear on stalks 8-12 inches above the foliage and last for several weeks.  Flower stalks can be removed once faded if desired.

Robb’s spurge grows in a wide range of conditions in shade to part sun. It spreads by underground rhizomes and makes a great evergreen ground cover.  In just a few years it can form a thick patch preventing many weeds from growing. This euphorbia multiplies most rapidly in well drained moist rich soil, but will grow well in average to dry soil typically found under trees. Robb’s spurge may be a little too aggressive for general use in the perennial border, but is a good candidate for problem areas. It makes a good substitute for groundcovers such as English ivy, vinca vine, monkey grass and pachysandra.

Robb’s spurge is beautiful in the shade garden paired with woodland phlox (Phlox divaricata) or forming a skirt around the beautiful chartreuse foliage of ‘Little Honey’ oakleaf hydrangea (Hydrangea quercifolia 'Little Honey') or ‘Florida Sunshine’ anise shrub (Illicium parviflorum ‘Florida Sunshine’).

As with most euphorbias, the milky sap can cause skin and eye irritations and should not be ingested. These very attributes make the plant virtually pest free and deer resistant.

Robb’s spurge is not always easy to find, but well worth seeking out for your garden.


Jason Reeves is an Ornamental Horticulture Research Associate with the UT West Tennessee AgResearch and Education Center in Jackson and curator of the UT Gardens - Jackson. He creates the site's various seasonal horticultural displays, conducts research on herbaceous and woody ornamentals, and supports various educational programs. The UT Gardens in Jackson and Knoxville are a project of the UT Institute of Agriculture. Their mission is to foster appreciation, education and stewardship of plants through garden displays, collections, educational programs and research trials. The gardens are open during all seasons and free to the public. See http://utgardens.tennessee.edu/ and http://westtennessee.tennessee.edu/ornamentals/ for more information.

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Contacts:

Jason Reeves, UT West Tennessee AgResearch and Education Center, Jackson, 731-424-1643

Dr. Susan Hamilton, Director, UT Gardens, 865-974-7324

Patricia McDaniels, UTIA Marketing and Communications Services, 615-835-4570, pmcdaniels@tennessee.edu