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Controlling Adam’s Needle in Forages

Adam’s Needle in newly established Ecoturf perennnial peanut – photo by Shep Eubanks

Although not an extremely common weed in established and well managed pastures and hayfields, Adam’s Needle (Yucca filamentosa L.) can be a persistent and unwanted weed, especially in pastures that have been recently established in reclaimed timberland, or in areas of deep sandy soils.

This field of Ecoturf perennial peanut has a small infestation at this time, but like many difficult weeds, it can proliferate quickly if left unchecked.  The plant is easily recognized by the long white, threadlike filaments along the fringes of the needle like leaves as seen in Photo 2 below.

Photo 2. Adam’s Needle – Note the white filaments on leaf edges Photo by Shep Eubanks

Photo 3. Adam’s Needle tap root and ramets
photo by Shep Eubanks

Yucca plants are well adapted to sandy, dry sites.  It has a large well-developed tap root, and thick, rhizomatous roots, which are water and energy reservoirs that allow the plant to survive drought, and grow in many soil types including the deep sands of Florida.  It can regenerate even after completely losing the top of the plant. The sharp blue green leaves are a hazard to both humans and livestock.  Moderate to dense populations decrease forage utilization and availability.  If left untreated, the population density can reach 2,000 plants per acre!

New plants can be produced by seeds, but the parent plant can also colonize an area through the growth of ramets (clones of the mother plant).  These structures are easily seen in Photo 3.

The plant has an interesting history.  It was used by Native Americans to produce soaps, and for medicinal uses (see the USDA Fact sheet on Adam’s Needle for more information on the history and biology of the plant).

The most effective control measure for this undesirable pasture weed is individual plant, spot spray treatments of a triclopyr ester such as Remedy Ultra as a 20% solution mixed with either 80% diesel or basal oil.  Apply the herbicide directly to the middle of the crown of the plant.  Careful application only on the targeted weed is essential. This mixture can cause significant damage to non-target grasses and legumes from over-spray.   Currently there are no effective broadcast treatment options available.