Smooth and Downy Brome Identification and Control
In the early spring before Kentucky bluegrass breaks dormancy and after Kentucky bluegrass shut down for the season in the fall, smooth brome stands out as a course textured patch in your lawn, sod farm, golf course rough, or sports field. During the growing season, its color and texture are comparable to Kentucky bluegrass and is not as much of a nuisance.
Both brome species (Smooth and Downy) can act as weeds in high quality turf areas. Smooth brome has many desirable characteristics to function as a useful turfgrass species; however, its poor density limits the use to low-maintenance areas.
There are several identification traits distinguishing brome grass from many other weeds. The sheath is nearly closed, giving it a V-neck sweater appearance. Brome has a rolled vernation, hairy sheaths and blades as well as a distinctive “watermark” (or W-shaped) on its leaves as seen below in Photo 1. Its spindly-natured leaves, small membranous ligule, and winter annual growth habit can usually identify Downy brome. Brome spreads rapidly by its extension rhizome system and its seeds are often carried by wind/birds from low maintenance areas to well-maintained turf.
There is no guaranteed selective control for Smooth brome in Kentucky bluegrass, creeping bentgrass, or perennial ryegrass turf. Early research from Zac Reicher and Matt Sousek at the University of Nebraska has shown earlier year application (June) rather than (July) will aid in Tenacity control of smooth brome in Kentucky bluegrass. This study will be replicated in 2014 and further data will be passed along as available. Downy brome can be controlled with the preemergence herbicide Siduron and post-emergent Sethoxydim (only for use in established fine fescue stands; tall fescue slightly tolerant).
In most cases, a nonselective, systemic herbicide should be used and multiple applications may be needed to effectively control brome grass.
Photo 1: Smooth bromegrass’s v-neck sheath and “w-shaped” watermark at midway point of leaf blade. Photo courtesy of Stephen K. Barnhart, Iowa State Press (1997).
Photo 2. Picture of Downy brome taken this week at the ISU research station. You can see the v-neck sheath as well as fine hairs.