Weed Watch: Palmer Amaranth


Palmer Amaranth

Palmer amaranth, also infamously called Palmer pigweed, is well-known for its aggressive growth and can often seem overwhelming to farmers. But with a zero-tolerance policy against weeds, you can turn the odds in your favor.1,2


Native to the southwestern U.S., Palmer amaranth is now found in 39 of the 48 continental U.S. states.3


In soybeans, Palmer amaranth can create yield losses of up to 79%.2,4


Young Plants

Often confused with similar weeds, plants can grow 2-3 inches per day. Leaves are diamond- to egg-shaped and often have a symmetrical leaf arrangement with a poinsettia-like appearance.2,5


Mature Plants

Uncontrolled plants can reach 10 feet, and no other pigweed species has terminal panicles that can reach 1-1/2 feet long.6


Seed Pain Points

A single plant can produce up to 1 million seeds and be responsible for generations of weeds in the same growing season.1,7

Palmer amaranth plants germinate from early spring all the way through the first killing frost, which means multiple products with multiple sites of action are needed to prevent weeds from getting big enough to produce. Palmer amaranth has rapidly gained a foothold in the U.S., and it is important to develop a weed management strategy to help prevent it from spreading.1,3

Keys to Managing Palmer Amaranth1,3,4

  1. Rotate crops

    to diversify herbicide programs and weed control strategies.

  2. Start clean

    with a burndown herbicide or tillage.

  3. Apply a pre-emergence residual application,

    using a residual product within 2 weeks before planting or prior to crop emergence.

  4. Apply a postemergence application to target small weeds early,

    before weeds grow taller than 4 inches.

  5. Prevent Seed Production.

    If weeds escape, use tillage or physically remove them before plants produce seed.

A Closer Look At Postemergence Application

The key to controlling Palmer amaranth is all about the right timing and the right products. Apply a postemergence herbicide 20-30 days after planting, when Palmer amaranth weeds are less than 4 inches tall and easier to control. Choose the right products with the right modes of action to give your crops the best defense against weeds:

XtendiMax® herbicide with VaporGrip® Technology 
  • XtendiMax® herbicide with VaporGrip® Technology, a restricted use pesticide, gives you up to 14 days of soil activity on certain small-seeded broadleaf weeds and is an effective tool to control emerged Palmer amaranth*
Warrant® Herbicide 
  • Warrant® Herbicide provides excellent levels of residual control on small-seeded broadleaf and grass weeds
Roundup PowerMAX® 
  • Roundup PowerMAX® herbicide controls emerged broadleaf weeds and grasses

With the right postemergence application, as part of a complete strategy, you can keep better control of weeds and help protect your crops to canopy.

Choose the System That Means Results

Choose the system that gives you advanced weed control and yield potential.

See System Overview