Barnyard Grass - Ask Extension
I'm fairly sure barnyard grass is what's showing up in my lawn especially along the driveway and sidewalk areas.
Is it an annual and the plants will n...
Knowledgebase
Barnyard Grass #470716
Asked July 15, 2018, 11:02 PM EDT
I'm fairly sure barnyard grass is what's showing up in my lawn especially along the driveway and sidewalk areas.
Is it an annual and the plants will not return next year except for new ones or can it be treated with something now without harming the rest of the lawn? I've been able to pull some out when we've had rain but others are more difficult to get the roots. Would using crabgrass preventer in the spring have stopped it from germinating? Also wondering if I would use a crabgrass preventer in the spring would I be able to use the grass clippings in the garden and around other perennials and shrubs to hold moisture and hold down weeds?
Brown County South Dakota
Expert Response
I think you may actually have crabgrass in your lawn. It is a more common weed than barnyard grass but they are both annuals and have coarser texture so it could be either one. Barnyard grass is usually easier to pull than crabgrass since it doesn't tend to sprawl out along the ground and root down at the nodes. Crabgrass has a much finer seedhead than barnyard grass as well. But, if you are keeping it mowed, it probably will not produce any flower heads. The crabgrass will readily flower even when mowed fairly short. The seedhead of barnyard grass is similar but much coarser with larger seeds that are easily felt when you rub your fingers over the seedhead. Each spikelet also has a little awn on the end of it so it will feel more bristly. Compare the two pictures below to see which one is a better match. The first picture is of crabgrass with some seedheads developing. The second picture is of barnyard grass and a seedhead.
You could try a post-emergence crabgrass killer, but it is getting a little late in the season. Once the plants start to spread out along the ground and produce flower heads, they become much more difficult to control. Look for a spray that says for crabgrass, it will likely contain the herbicide quinclorac. Although I am not sure they will work on barnyard grass, because it wasn't on the label that I was able to find. So, check the labels to see if it is listed there as a weed it will control.
The good news is that the typical crabgrass preventers that you would apply in the spring should control both kinds of weedy grasses. We normally apply these about the time lilacs start blooming in your area. Then they will be effective until the early fall. Since both of these grasses are warm-season grasses, they do not start to germinate until we have had a few weeks of warmer weather to warm up the soil.
I was not able to find anything on the label that indicated that you could use the clippings as mulch in the garden. You could potentially see some damage to your vegetables through root uptake of the herbicide. Check the labels of the products you can find in your area for more information on that particular question.
You could try a post-emergence crabgrass killer, but it is getting a little late in the season. Once the plants start to spread out along the ground and produce flower heads, they become much more difficult to control. Look for a spray that says for crabgrass, it will likely contain the herbicide quinclorac. Although I am not sure they will work on barnyard grass, because it wasn't on the label that I was able to find. So, check the labels to see if it is listed there as a weed it will control.
The good news is that the typical crabgrass preventers that you would apply in the spring should control both kinds of weedy grasses. We normally apply these about the time lilacs start blooming in your area. Then they will be effective until the early fall. Since both of these grasses are warm-season grasses, they do not start to germinate until we have had a few weeks of warmer weather to warm up the soil.
I was not able to find anything on the label that indicated that you could use the clippings as mulch in the garden. You could potentially see some damage to your vegetables through root uptake of the herbicide. Check the labels of the products you can find in your area for more information on that particular question.
