Grassy Weed - Ask Extension
Hi - Are the grass (lawn) weeds in the attached image Rough Bluegrass? I believe they are and just want to confirm. Or, are these not weeds and just...
Knowledgebase
Grassy Weed #451432
Asked May 03, 2018, 2:17 PM EDT
Hi - Are the grass (lawn) weeds in the attached image Rough Bluegrass? I believe they are and just want to confirm. Or, are these not weeds and just overgrown perennial rye grass plants (what my lawn is)?
thx
Kyle
Linn County Oregon
Expert Response
Hello,
It's possible, but I can't tell from your photos.
To I.D. grass, I need to see a close up of the leaf surface, leaf tip, stem shape, and the ligule. If you do a google search on "grass ligule", you will see the kind of photos I need. Take the photos on macro mode from about 2 - 4" inches away and make sure they are in focus. Also, be sure they are taken and/ or uploaded with high enough resolution (VGA (640 X 480) or higher. When I click on the photos to blow it up bigger, they are blurry.
If you send good photos, I will likely be able to I.D. the grass. I have attached 3 photos that show of characteristics of Rough bluegrass.
The challenge with identifying Rough bluegrass in the spring is that it can look completely different if it is trying to flower. In the first photo, it is coarse textured and you can see the purple stolons growing sideways. Keep in mind, not all the stems will be purple. It is much finer textured with a smaller ligule when it is NOT trying to flower. It is also light yellow in color, and has wimpy leaf blades which are shinny on the bottom.
Two other ways to identify it are:
1) it is the fastest growing grass in the winter in cool weather. If you haven't mowed your lawn for a while, you will see light green patches that are taller than the other grasses. It does not flower in the winter. It loves cool, shady areas and you will often find it in the shadiest areas of your lawn.
2) when summer starts and it gets got, it turns red and starts going dormant faster than any other grass.
The other general characteristics are that the top of the leaf blade is smooth, as opposed to perennial ryegrass, bentgrass, and tall fescue that are ridged. I would encourage you to look at a perennial ryegrass leaf surface to calibrate your eye to what the ridges look like. This is a relative comparison as if you looked closely with a hand lens, you will see ridges on Rough bluegrass as well, but with the naked eye, they are much more pronounced with perennial ryegrass, bentgrass, and tall fescue. Additionally, it has a boat shaped tip (along with annual bluegrass and Kentucky bluegrass) vs. a sharp pointed tip of the other grasses. Also, the stems and new leaves emerging are folded (Perennial ryegrass is folded too, but bentgrass and tall fescue are rounded).
Lastly, in the first photo I sent, you can see the flowers. These flowers are from annual bluegrass, not Rough bluegrass. Annual bluegrass has similar characteristics to Rough bluegrass with some minor differences, but it doesn't get coarse textured like Rough bluegrass when it flowers. In general, if you are mowing regularly, you won't see Rough bluegrass flowering because the stalks are so long they get mowed off. The only exception might be if a flowering stem is spread out wide and stays close to the ground below the level of the mower. But this doesn't happen very often.
This website has some pretty good photos of annual bluegrass flowering and Rough bluegrass turning red in the early summer. https://www.newgarden.com/newsletter-articles/undesirable-bluegrasses
I hope his helps. If you want to send more photos, I can try and I.D. the grass.
It's possible, but I can't tell from your photos.
To I.D. grass, I need to see a close up of the leaf surface, leaf tip, stem shape, and the ligule. If you do a google search on "grass ligule", you will see the kind of photos I need. Take the photos on macro mode from about 2 - 4" inches away and make sure they are in focus. Also, be sure they are taken and/ or uploaded with high enough resolution (VGA (640 X 480) or higher. When I click on the photos to blow it up bigger, they are blurry.
If you send good photos, I will likely be able to I.D. the grass. I have attached 3 photos that show of characteristics of Rough bluegrass.
The challenge with identifying Rough bluegrass in the spring is that it can look completely different if it is trying to flower. In the first photo, it is coarse textured and you can see the purple stolons growing sideways. Keep in mind, not all the stems will be purple. It is much finer textured with a smaller ligule when it is NOT trying to flower. It is also light yellow in color, and has wimpy leaf blades which are shinny on the bottom.
Two other ways to identify it are:
1) it is the fastest growing grass in the winter in cool weather. If you haven't mowed your lawn for a while, you will see light green patches that are taller than the other grasses. It does not flower in the winter. It loves cool, shady areas and you will often find it in the shadiest areas of your lawn.
2) when summer starts and it gets got, it turns red and starts going dormant faster than any other grass.
The other general characteristics are that the top of the leaf blade is smooth, as opposed to perennial ryegrass, bentgrass, and tall fescue that are ridged. I would encourage you to look at a perennial ryegrass leaf surface to calibrate your eye to what the ridges look like. This is a relative comparison as if you looked closely with a hand lens, you will see ridges on Rough bluegrass as well, but with the naked eye, they are much more pronounced with perennial ryegrass, bentgrass, and tall fescue. Additionally, it has a boat shaped tip (along with annual bluegrass and Kentucky bluegrass) vs. a sharp pointed tip of the other grasses. Also, the stems and new leaves emerging are folded (Perennial ryegrass is folded too, but bentgrass and tall fescue are rounded).
Lastly, in the first photo I sent, you can see the flowers. These flowers are from annual bluegrass, not Rough bluegrass. Annual bluegrass has similar characteristics to Rough bluegrass with some minor differences, but it doesn't get coarse textured like Rough bluegrass when it flowers. In general, if you are mowing regularly, you won't see Rough bluegrass flowering because the stalks are so long they get mowed off. The only exception might be if a flowering stem is spread out wide and stays close to the ground below the level of the mower. But this doesn't happen very often.
This website has some pretty good photos of annual bluegrass flowering and Rough bluegrass turning red in the early summer. https://www.newgarden.com/newsletter-articles/undesirable-bluegrasses
I hope his helps. If you want to send more photos, I can try and I.D. the grass.
Added 3 more pictures, not sure if they help. It looks like rough bluegrass to me. Happy to take a sample and drop it off at the extension office in Tangent if my pictures aren't adequate.
If it is rough bluegrass, how do i get rid of it? I have a second year lawn and this stuff has come in everywhere. In early spring, I used a pre-em (Prodiamine, active ingredient), but didn't seem to help much with this weed.
thx
Kyle
If it is rough bluegrass, how do i get rid of it? I have a second year lawn and this stuff has come in everywhere. In early spring, I used a pre-em (Prodiamine, active ingredient), but didn't seem to help much with this weed.
thx
Kyle
Kyle,
From your latest photos, it's definitely NOT rough bluegrass. It is rolled in the stem and ridged on the top of the leaf surface. It has the characteristics of annual ryegrass. Annual ryegrass can be contained in certain seed mixes and can be a weed grass in seed mixes. It is also called "Italian Ryegrass". Since you recently planted your lawn, that would be my guess.
What seed mix did you use to plant your lawn? Also, when did you plant it (month/year)? Also, since it appears you live near Corvallis, I may be able to come look at your lawn. Send me an email to <personal data hidden>.
Good luck.
From your latest photos, it's definitely NOT rough bluegrass. It is rolled in the stem and ridged on the top of the leaf surface. It has the characteristics of annual ryegrass. Annual ryegrass can be contained in certain seed mixes and can be a weed grass in seed mixes. It is also called "Italian Ryegrass". Since you recently planted your lawn, that would be my guess.
What seed mix did you use to plant your lawn? Also, when did you plant it (month/year)? Also, since it appears you live near Corvallis, I may be able to come look at your lawn. Send me an email to <personal data hidden>.
Good luck.
