Myrtle spurge, a bright green ground cover with yellow and red flowers, is a very visible weed showing up on hillsides around town. In the Willamette valley myrtle spurge is a garden ornamental. In arid Eastern Oregon it is a class B invasive weed. It crowds out native vegetation by preventing other plants from growing nearby. Invasive weeds are not just a problem for ranchers and farmers.
Warming temperatures are triggering dormant myrtle spurge seeds to sprout. Mature plants are flowering and developing seed pods which will soon spread more seeds. When disturbed the ripe seed pods can disperse seeds 15 feet. The small seeds are easily carried by our strong winds.
Now is the time to help defend Pendleton from new myrtle spurge plants getting established along with removing older plants before they can spread new seeds. There is no silver bullet to eradicate myrtle spurge. The best tactic involves digging up the plants. Four-inch trenching shovels work well. Digging up the plant stops seed production, but it may come back if the roots regenerate. Try to get at least 4 inches of tap root. It may take more than one year to get this invasive weed under control. Year two should have fewer plants returning.
Now is the time to act! Enlist neighbors, grab shovels and clear myrtle spurge from your neighborhood. If you join the battle, protect your skin as the milky sap is a skin/eye irritant for humans and animals. Pants, long sleeves and gloves are recommended.
Dispose of the plants as garbage. Do not compost or recycle as yard debris. The seeds will contaminate the compost. Attacking with power equipment like mowers and tillers are counterproductive as mowers only clip the top off the plant while the roots continues to grow. Tillers chop up the tuberous roots and spread them like seed potatoes.
Chemicals like 2,4-D can be effective when applied in the fall. However, that is after the plants have set seed for the next year. The seeds can remain dormant for years resulting in the need of repeated applications.
Myrtle spurge is not the only invasive weeds in our area. You can also use your shovels to remove numerous types of thistle plants and puncturevine (aka goat heads).
Pictures and info for noxious weeds can be found in “Field Guide to Weeds of Eastern Oregon.”