12 May 2015

2 minute read

Historically, smooth bedstraw is first found in fields that have been poorly managed hayfields with low fertility and high acidity (low pH), or pastures that have been continuously grazed or underutilised.

This is according to plant experts at the University of Maine who offer advice on beating the weed. 

As farm fields are either abandoned or less intensively managed, soils become more acidic, with fertility dropping and smooth bedstraw proliferating.

Smooth bedstraw tolerates low soil nitrogen and soil acidity better than desired forage species.

Lately, however, smooth bedstraw has been invading better-managed stands of forages and adapting to more variable environmental and soil conditions.

Its present area of adaptation ranges from southern Canada to as far south as Georgia.

These management points, from the University of Maine, should help to limit the spread of bedstraw in fields.

• Manage your hayfield by testing the soil and keeping nutrients and pH at levels where grasses and legumes will thrive. Apply nutrients and lime as needed.

• Keep bedstraw plants from flowering, setting, and spreading seed, no matter which additional control option you use. If you manage hayfields, try to get the haycrop mowed before bedstraw sets seeds. This will help control the spread, give the grasses a more competitive edge, and also provide you with a better-quality crop. Be aware of a second flowering and seed-production period in August!

• Make sure to control the spread of seed. Mowers, balers, rakes, and tedders can carry substantial amounts of seed from infested fields to clean fields. Remove any source of seed from equipment when moving from field to field. Research is still inconclusive about the spread of bedstraw via manure applications.

• Tillage and rotation is very effective in killing perennial crowns and new seedlings that may develop. Consider a weed-controlling cover crop such as buckwheat or sorghum-sudangrass hybrids as part of your reseeding regime. Remember that a new seeding will need optimum management to keep smooth bedstraw from re-invading the field.

• If using an herbicide such as Crossbow, Milestone, or Forefront R&P, make sure you control the weed's seed rain during the season prior to application, and understand that all broadleaf plants, including desirable clovers or alfalfa, will also be killed. If you decide to use glyphosate to renovate a pasture and kill perennial crowns of bedstraw, controlling seed rain is also critically important. Glyphosate treatments are most effective in late-summer applications.

• Since bedstraw is so invasive, a neighbourhood approach may be necessary to slow down the spread of this weed.

A well-managed, fertilised hayfield with a dense stand of perennial forages will be a good defence against invasion by smooth bedstraw.

Further Reading

More University of Maine advice on controlling bedstraw is available here.