Published on Saturday, 27 August 2016 14:35
Written by David Gardner
If you are noticing a weed with bright yellow flowers in lawns now, it may very well not be dandelion (which is generally not in bloom right now) or black medic. In fact, there is a good chance that it is Birdsfoot trefoil (Lotus corniculata
). Birdsfoot trefoil has long been used as a pasture crop and is known to be able to escape from its intended site. But it is only in the last decade that it has become increasingly visible in managed turfgrass - first in waste areas and abandoned fields, then parks and roadsides, and now residential lawns.
Birdsfoot trefoil is a long lived perennial in the legume family. It has bright yellow pea-like flowers, primarily in June and July. The pod-like fruit resembles a birds foot, hence the common name. The leaves have 3 leaflets similar to black medic. While capable of reaching heights of 2 feet, it adapts very well to mowing and forms dense mats in mowed turf.
Birdsfoot trefoil is a very important crop plant for hay and pasture production. Use of birdsfoot trefoil in pastures results in a 10 fold increase in forage yield thus higher production of beef cattle. In fact, there is research underway to produce glyphosate tolerant birdsfoot trefoil for use in production agriculture. Since it is not widely considered a weed, it does not appear on very many herbicide labels. Research at OSU has concluded that combination herbicide products that contain clopyralid or fluroxypyr are effective for control.