Myrtle Spurge

Myrtle spurge is an herbaceous perennial in the Euphorbiaceae (spurge) family. It produces multiple low-growing stems from the crown that may reach 8 to 12 inches tall and 12 to 18 inches wide. Stems are not usually branched. Leaves are alternately arranged and spiral around the stem. Leaves are thickened, waxy, and may be blue, silver, gray, or green. Leaves are ovate or spatulate and usually less than 1 inch in length. Myrtle spurge flowers from late spring to late summer. Flowers occur in umbles at the end of stems. Flowers are cyathia, a cup-shaped whorl of bracts (false petals) surrounding a cluster of stamen flowers and a single pistil flower similar to a poinsettia. Each cyathium has heart-shaped, bright yellow to yellow-green bracts. Myrtle spurge has an extensive network of rhizomes. Seeds are produced in capsules, with 3 seeds per capsule, and the seeds are small and gray. Seeds are dispersed with explosive force and may be shot up to 15 feet from the parent plant.

All parts of the plant secrete a milky latex. This sap is toxic to humans, most livestock, and wildlife and can irritate skin and eyes, causing blindness.

Myrtle spurge is native to Eurasia. It was first introduced into North America as an ornamental. It creates dense infestations by spreading rhizomes and seeds, and spreads to new locations by seeds and root fragments. It is found in landscaping, pastures, roadsides, agricultural crops, and disturbed sites.

Prevention strategies and cultural control strategies should be utilized as much as possible. Utilize native plants for landscaping. Purchase certified weed-free gravel when possible, and utilize topsoil from clean sites.

There are no biological controls for cypress spurge available at this time.

Hand pulling and digging out of the taproot and lateral rhizomes may be effective for removing small patches of myrtle spurge, but these must be repeated throughout the growing season. Wear gloves and long sleeves when handling myrtle spurge as the latex is highly irritating and potentially blinding. Mowing at regular, two week intervals can prevent seed production. Intensive grazing with sheep or goats may reduce seed production. Care must be taken to prevent spreading seeds to a new area after grazing. Hold animals in a pen for 3 to 5 days after grazing. Myrtle spurge is toxic to cattle and horses.

Larger infestations can be controlled with herbicides. Spring and early summer treatments prior to bloom are effective. Fall treatments after the first frost are effective as the herbicides are readily moved into the root system. Read the label before using any herbicide. Contact TCWP if you have any questions about application rates or how to use an herbicide.

• Euphorbia myrsinites. North Carolina Extension Gardener Plant Toolbox. North Carolina State University Extension.
• Myrtle Spurge. Washington State Noxious Weed Control Board.
• Myrtle Spurge: Rangeland, pasture, and riparian site recommendations. 2015. Colorado Department of Agriculture.
• Euphorbia myrsinites. Mahr, Susan. 2009. Wisconsin Master Gardener. University of Wisconsin.