How To Get Rid Of Bromegrass

Brome grass is one of the top forage crops for livestock, often mixed with fescue in grazing pastures, but it’s also a common weed that spreads from agricultural fields to neighborhood lawns. Like crabgrass and dallasgrass, hearty brome is difficult to deal with since it blends in with your existing lawn. Here, we’ll go over how to control and get rid of this problematic weed.

Identifying Brome

Bromegrass has over a hundred species, some of which are annual and others that are perennial. All types of brome, however, have rhizomes (below-ground root extensions) that allow them to creep around and grow in patches throughout a lawn. Some of the most widespread types of bromeweed include:

  • Smooth brome (Bromus inermis) – a cool-season perennial
  • Downy brome – (Bromus tectorum) a cool-season annual
  • Japanese brome – (Bromus japonicus) another cool-season annual

Brome is one of the first grasses up in the early growing season, with seeds germinating in fall and winter, then growing aggressively in the spring. Smooth brome is particularly difficult to get rid of since its root system goes dormant, while downy and Japanese brome relies on only their seeds to regrow in the next season.

Depending on your grass type, brome may or may not be easy to notice amongst your grass. It has wide, flat blades and looks similar to crabgrass. When brome goes to seed, however, it puts up tall shoots that can grow to 30 inches when undisturbed. Brome grows best in areas that don’t get a lot of attention, like along highways, in large fields, as well as in lawns that don’t get mowed frequently enough. Brome does well in moisture-retaining soil, like clay-heavy profiles.

One way to notice brome is by looking at the shoot leaves, which tend to have a W or M formation in the center of the leaf. When brome grass is ready to drop its seeds, it turns a purple color and stands out against the otherwise green grass.

Keeping Bromeweed Out Of The Lawn


One of the easiest ways to keep brome, and most other weeds, out of your lawn is by mowing the grass regularly. Brome puts out tall shoots with lots of seeds on the ends, but if the grass is mowed weekly and isn’t able to put out these seed heads, no new seeds will be distributed across the yard.

Mowing regularly also helps your grass stay in healthy condition and better able to compete with any brome that tries to get established. When you mow after brome flowers have popped up, be sure to use a bag on your mower to collect the clippings, which may contain viable seeds.

If bromegrass becomes too widespread in the lawn, the only way to get rid of it is to till deeply, destroy the root system, and regrow your lawn. If it’s spotty or patchy growth, however, you can use a glyphosate-based herbicide to get rid of the grass.

What Herbicide Kills Brome?

While brome seeds don’t stay in the ground for more than a couple of years, their early and extended germination periods give them an advantage. Bromegrass can germinate from the end of winter through mid-spring and throughout fall. Using preemergent herbicides will help keep brome seeds from sprouting, but once they do, the weed may become a problem.

Grassy weeds are so difficult to get out of a lawn since they blend in as they grow amongst the turf grass. Brome is especially hearty, and the only weed killer that really works on it is Roundup, whose active ingredient is glyphosate. Be careful using this non-selective herbicide, however, because it can damage grass as well as the weeds.

For this weed, it’s important to follow the directions closely and use the full dose that is recommended on the label for the number for your yard. The plant needs to absorb the product for it to work into the dense rhizomatic root system. Half-dose herbicide applications won’t be strong enough and may only damage the leaves rather than the roots as well.

If you can time it to apply the herbicide to be in fall after the first frost, it’s the best time to target bromegrass. The roots will be actively absorbing nutrients to store for winter dormancy and will readily take up the chemical.

Cold ground temperatures (or freezing, based on your location) will then finish off any roots that were only weakened. Since this is a cool season grass, the other good time to apply post-emergent herbicide would be at the end of spring, before it goes into summer dormancy.