Over the past couple of weeks I’ve had a few calls and emails generally about clumps of fast growing grass in lawns. Generally, I see this mystery weed as 1 of following weeds.
- Tall Fescue (K31 in a tall fescue yard, or tall fescue in a bluegrass, buffalograss, or Bermudagrass lawn)
- Orchardgrass in any lawn, but very common in K31 lawns.
- Bromegrass in any lawn, but typically in areas that are near farm land, pasture land, or vacant lots.
- Yellow Nutsedge in any lawn, but not during this time of year…typically I’ll get calls about this in June, July, and Aug.
1. Tall fescue. I was going to show you these pictures and let you guess what they are but here goes. The first one is clumps of tall fescue in a tall fescue yard that has been ‘fertilized’ by the dog. It just goes to show you, how underfertilized this lawn is.
The next two pictures below are of K31 in a tall fescue/bluegrass lawn. The first one was overseeded with K31 at some point in it’s history…the K31 is the light green colored grass. It has just been mowed, but if I were to come back in a week, the K31 would be much taller than the darker colored turf-type tall fescue. So K31 has a double negative when it comes to well-maintained fescue lawns, it grows rapidly and needs to be mowed more often, and it is a light green, so most people will fertilize it more frequently to maintain a darker color, which causes it to grow even more rapidly, with even more mowing.
The second picture is a clump of K31 growing in a yard next to the one above. It had not been mowed yet, so you can more easily see how much taller it is. You can also see how much wider and thicker the leaves of K31 are compared to turf-type tall fescues.
2. Orchard grass is a cool season perennial like tall fescue. And it is a bunch-type/clump-forming grass like tall fescue. It generally has wide blades and a dark color. The main differences between tall fescue and orchardgrass is that orchardgrass has a very flattened stem with folded vernation whereas tall fescue has rolled vernation. Moreover, tall fescue has a pointed leaf tip whereas orchard grass has more of a rounded, boat-shaped leaf tip. And finally, orchardgrass has a very large, membranous, white ligule. (that means it has a white piece of skin like material where the leaf blade joins the leaf sheath.) It is usually so large and so easy to see, I often use orchard grass ligules when I’m teaching grass ID to people. Below are 3 pictures of orchardgrass close up. (sorry if they are a little out of focus….darn camera kept focusing on the ground)
Ward Upham recently releases a news article through KSRE about orchard grass.
3. Bromegrass. Typically, bromegrass spreads by rhizomes, so it may not be a distinct clump, but it is definitely fast growing. I wasn’t able to find any bromegrass to take a picture of, but the University of Missouri has a good page on bromegrass. The key charachteristics of bromegrass can be summed up by this photo by Stephen K. Barnhart, Iowa State Press (1997). The sheath closes back in on itself and forms a v-neck appearance. And the leaf blades often have a “M-shaped” (or “W” depending on how you are holding the leaf) water mark or branding on them, as seen below.
The downside is there is no real selective control to remove any of these 3 weeds from cool season lawns. There are products that can remove them from warm season lawns. But for control in cool season lawns, you can simply dig up the clumps or spot spray the clumps with a non-selective herbicide, like Round-Up. If the weeds are widespread across the lawn, then the only option is to kill the whole yard and start over. Kill it and reseed or sod it in September.
4. Yellow Nutsedge. We will talk more about it later this year, but it is a warm season perennial and it can be selectively controlled in any type of turfgrass with Sedgehammer.
Anybody else seeing these 3 weeds? Are they giving you headaches?