By Blake Jackson
Yellow pastures in spring often signal buttercup infestations, a sign of underlying pasture management issues rather than a desirable sight. Don't wait for fields to turn completely yellow before acting.
The most effective buttercup control involves a combination of mowing and timely herbicide applications. Mowing as low as possible in early spring, before flowering, helps reduce seed production.
Routine mowing throughout the season can further limit weed seed development and encourage grass growth. However, a well-timed herbicide application in early spring (mid-March through April) is crucial for optimal control.
Common herbicides include 2,4-D, 2,4-D + dicamba, metsulfuron/MSM, or Crossbow. Ensure thorough coverage by using higher spray volumes (at least 15, ideally 20+ gallons per acre). Spraying flowering buttercups is generally ineffective.
For spring applications, ensure air temperatures are consistently above 50°F for several days. Be aware that these herbicides will harm or eliminate legumes like clover.
A lower rate of 2,4-D might suppress buttercup while minimizing clover damage, but it may only provide temporary control and stunt clover growth.
Fall herbicide applications can offer some control but are less effective than spring treatments. Common buttercup species in PA include bulbous, creeping, tall, and small flower buttercups, most of which are perennial or act as winter annuals.
Lesser celandine can be mistaken for buttercup. Dense buttercup infestations often indicate overgrazing and poor forage stands, highlighting the importance of good agronomic practices, including proper fertility, soil pH, grazing and mowing management, alongside well-timed herbicide use.
Now is also the time to manage poison hemlock, though it can be confused with wild chervil. Both belong to the carrot family and have similar lacy foliage.
Poison hemlock is a biennial, while wild chervil is biennial or a short-lived perennial. Both form rosettes in their first year and bolt with white flowers in umbels in late spring/early summer, reproducing by seed.
Poison hemlock has hairless, purple-blotched, hollow stems and a parsnip-like odor when crushed, growing 2-6 feet tall. Wild chervil has grooved, hairy, hollow stems, reaching 1.5-4 feet, with finger-like seed clusters.
Poison hemlock is generally more toxic, with sap potentially causing dermatitis. Ingestion by humans or livestock can lead to muscle paralysis and suffocation. Control involves digging individual plants or mowing/trimming larger infestations.
Effective herbicides, best applied in the fall rosette stage or before spring bolting, include 2,4-D + dicamba, Crossbow, NovaGraz, or glyphosate (spot treatment).
Photo Credit: gettyimages-r-j-seymour
Categories: Pennsylvania, General, Livestock