Bright yellow green patches popping up in your pastures this spring is not a sight to look forward to. Leafy spurge is experiencing its spring growth now too.
While there are many species livestock producers consider pasture weeds, one that is held in particular dislike is leafy spurge. Not only is this hardy perennial on the state noxious weed list, but it spreads aggressively and is hard to control once established. Standing 1-3 ft. tall, spurge plants have simple deep-green, lancelet leaves. Plants flower in late May to early June with bright yellow-green bracts surrounding the true flower. If you are still unsure if the plant you are looking at is spurge, one tell-tale sign is the milky sap the entire plant produces when damaged. This sap is irritating to cattle, preventing them from grazing spurge patches.
Control of spurge is difficult due to its prolific root system and aggressive reproductive tendencies. Leafy spurge spreads by both seed and buds on rhizomes and roots. A single plant can produces on average 140 seeds, spreading them up to 20 ft. away when mature. The root system can stretch to depths of 15 ft. This prolific root system allows spurge to bounce back after control measures and when damaged, can produce new plants from numerous root buds. This makes one-time tilling more likely to spread out patches and produce more plants than provide control.
Biological controls like spurge feeding insects or grazing by goats or sheep can be utilized successfully to limit aboveground growth but will not control plants completely. Both options can be time intensive and take some research and planning to implement effectively. Cultural control methods like fire and mowing can be utilized to similar effect as biological controls, damaging aboveground growth primarily. Both methods can be utilized with proper timing to limit seed production and stress plants so a later herbicide application is more effective.
Multiple chemicals have action on spurge, however for spring treatments, control at bud or true flower stage is recommended. Early application at the bud stage is limited to 2,4-D ester or Picloram + 2,4-D mix. A later flower stage application opens up or options to Curtail/Cody/Stinger, Streamline, a mix of Sharpen + Plateau or a mix of Overdrive + Tordon.
Unfortunately, a single treatment will not control spurge once established, so continued monitoring and retreatment is needed. An effective strategy is pairing spring applications that prevent seed production will a fall treatment to control new growth.
Whether spraying in the fall or spring, marking spurge patches physically, by map, or with GPS is essential for full control. Not only does this make repeat spraying of patches easier, but ensures dormant seed just now germinating or a stray plant haven’t been missed. With its prolific reproductive capabilities, even one mature spurge plant that escaped can quickly form a new patch.
Leafy spurge is not an easy opponent to take on. It can easily take over a pasture, reducing grazing capacity, however with regular treatment and monitoring, it can be contained and controlled.
-Ben Beckman is a beef systems Extension Educator serving the counties of Antelope, Cedar, Knox, Madison, and Pierce. He is based out of the Cedar County Extension office in Hartington. You can reach him by phone: (402) 254-6821 or email: firstname.lastname@example.org.