Euphorbiaceae or Spurge Family
Growth Habit: Perennial, grows up to 3 feet tall.
Leaves: Long narrow leaves, usually dropping.
Stems: Branched near top, hairless, entire plant contains milky white sap.
Flowers: Inconspicuous, surrounded by large heart shaped floral leaves that turn yellow green near maturity.
Roots: Vertical and horizontal roots. Main vertical roots can penetrate 26 feet deep. Horizontal rhizomatous roots, near the soil surface, extend outward from the parent plant 15 feet per year.
Seeds: Produces up to 140 seeds per plant, viable up to 8 years or longer. Projects seeds up to 15 feet from the base of the plant. Seeds float on water.
Reproduction: Large number of buds on each root and by seed. Each bud is capable of producing a new, independent plant.
Habitat: Riparian areas to dry hills.
Handpulling: This is not an effective method of control for leafy spurge because of its extensive root system. Even seedlings that are a few weeks old have vegetative buds on their roots capable of producing new shoots when disturbed by pulling.
Mowing: This is not an effective method of control for leafy spurge.
Biological Control: Twelve different insect species have been released as biological controls for leafy spurge in the U.S. Of those, the Aphthona flea beetles have had the most success in establishing and suppressing leafy spurge. Different Aphthona species do better or worse dependent on the site conditions of the infestation (e.g. sun exposure, soil type and moisture), so care should be taken to choose the appropriate species for your site. Contact the Missoula County Weed District for additional information and for assistance with monitoring or additional releases.
Grazing: Grazing with sheep or goats that have been trained to eat leafy spurge can be an effective method of control. Persistent grazing over the long term can reduce stand density, reduce seed production and weaken the infestation, making herbicide and/or bio-control more effective. Grazing can be utilized at any time during the growing season as long as plants are green.
Herbicide: There are a number of herbicides that are effective on newly established or small infestations of leafy spurge. Due to the extensive root system and the need for repeated treatments over a period of many years, management of large infestations of leafy spurge through the use of herbicides alone may be uneconomical and have an overall negative effect on your site. The following herbicides have been labelled for control of leafy spurge. Always consult product labels and read them carefully to ensure correct species/land management usage and chemical application.
|Trade Name:||Active Ingredient:||Rate:||Efficacy:||Comments:|
|Tordon 22k||picloram||1-2 qts/acre||most effective at full flower or fall||Cannot use near surface water, shallow water, landscaped areas and current or future vegetable gardens (Restricted Herbicide - need an applicator license to use.)|
|Tordon 22k + 2,4-D||picloram + 2,4-D||1-2 pts picloram + 1 qt 2,4-D/acre||most effective at full flower or fall; repeat annually for 3 years||Cannot use near surface water, shallow water, landscaped areas and current or future vegetable gardens (Restricted Herbicide - need an applicator license to use.)|
|Plateau||imazapic||most effective if used in fall prior to first frost|