Johnson Grass

[Kate]

Does anyone know what to use to kill Johnson Grass (a noxious weed) in my lawn?

Thanks.

Kate

[Eggs Zachtly]

There's nothing I know of that you can purchase (as a homeowner), that you can spray on Johnson Grass (Sorghum halepense) in established turf, that will kill it and not harm the turfgrass.

Are you *sure* you've positively identified it as S. halepense? What color is the midvein in the blade?

S. halepense spreads by rhizomes (making pulling the established plants next to impossible), as well as seed (not letting it set seed will eliminate thst possibility). It also prefers very wet areas. If this is the case, your best recourse may be to remove all of the turf in that area (making sure to get all of the rhizomes out), and re-grading the low area (or providing some other form of drainage, such as a French drain). Don't just till the area, you'll end up with possibly thousands of more plants (from segmenting the rhizomes). *REMOVE* the infected area, completely.

[Kate]

Hi,

I should have given you more information.

I had a very bad case of Johnson Grass when I bought this home. The first year I did not have time to deal with it. The second year I did not know what it was, so I diligently dug each weed out by hand. little did I know that the rhizomes spread like crazy and I was not solving the problem.

I got two professional opinions and both told me it was Johnson Grass. I killed 3/4 of my lawn with Roundup, which they recommended. This is a five-year process. While I have reseeded, and am constantly on this awful weed, I am gaining the battle. This will be my fourth year fighting it.

The patches I killed last August - October are now filling in nicely, however, come late summer, I know I will be spraying more areas.

What I do is hand paint the leaves of this stuff, and for the most part, just the plant dies. But, there is some dead grass that has to be reseeded the next year.

It does get better each year, but I was mostly reaching out to find out if anyone else has had experience with this monster, and what they used to fight it.

I also keep my lawn mowed very short, and I don't over water it.

Thanks, and sorry if I mislead you.

Kate

[Eggs Zachtly]

Some people consider the "big" lawn care companies such as Tru-Green to be "professionals". ;) I hope you chose someone with a degree in turf grass management, such as a golf course superintendant to provide the opinion.

I'll ask again, what color is the midvein down each blade of the offending grass?

A painstaking method, but I admire your diligence. =)

We fight it on creekbanks, but it's not an established turf-area. Simply keeping it cut to the ground level will keep it from A. developing seedheads, and B. photosynthesizing, causing the rhizomes to eventually exhaust their food stores, with the plant eventually dying.

On the rare occasion that it invades a turf area, the area is usually re-sodded, though there *are* products on the market, available to professional applicators, that show promise with good results. You, as a homeowner, can't purchase them .

Mowing your lawn "very short" can contribute to weed issues. Allowing the turfgrass to grow a bit taller, and thicker, keeps the sunlight from reaching the low growing weeds, which eventually die. S. halepense plants that have already matured are tough though, and will stay with the grass no matter the height. This will keep them from going to seed, eliminating one way of it spreading. The height of the grass is also dependant upon what variety it is. What type of turfgrass are you trying to establish? Fescue? Bluegrass? Zoisa?

Regardless, if it *is* S. halepense, it prefers wet locations. If it's prominent in an area of your yard, you have *some* kind of drainage issue that should be addressed. It's also possible that it's been mis-diagnosed by the "professionals" you contacted. =)

No worries. You didn't mislead, rather you left out some information. That's what discussions are for. =)

Some photos of the plant and areas, posted somewhere online and linked here, would be quite helpful! There are quite a few that lurk here, who are quite knowlegable in turf care. =)

[Kate]

Hi,

One of the two professionals I called to look at my problem has a degree in this type of stuff. He actually owns a weed and feed type store, and we are so fortunate to have him in our small town.

I don't have a lot of patience, but painting the tips of these weeds is no big deal, as I don't have that many. My neighbor is doing the same thing, (thank Goodness or this problem may never go away)and has a good handle on it.

The stems of Johnson Grass are solid with prominent swollen nodes. The mid vein is white. I have friends who are farmers and they have tons of this on some of their land. I imagine the wind and birds create this nasty problem.

Despite the bald spots I get toward the end of summer, from applying Roundup (although not as noticeable now as I feel I am getting rid of the weeds), I still get plenty of compliments on my lawn. I use a pre-emergent in early March, and the lawn greens up beautifully. Weeds are not a problem except for the Johnson Grass.

I was just hoping a farmer, or somebody, would know of a secret fix.

Thanks again.

Kate

[Eggs Zachtly]

[...]

You imagine right, and it sounds like a definate positive ID. Sorry to be so persistent in asking about that, but so many come here using common names, and they're usually wrong. I just wanted to be sure. Thanks for putting up with that. =)

Great news on the pre-emergent. That, coupled with not letting the plants set seed in the first place, eliminates half the problem. Each plant can produce up to 5000 seeds.

I'm still concerned about drainage, simply because that's where it likes to grow. But, you know your property better than anyone, so if you don't think there's a water problem, there probably isn't. =)

Sorry, there's no "secret fix" that I've ever heard of. The only chemicals I know of are pretty hard-core, and not readily available to the home user. You may want to talk to the gentleman that owns that store, and see if he knows anyone that can apply one (or more) of the following:

fluazifop (Fusilade II) sethoxydim (Vantage) clethodim (Envoy) imazapic (Plateau)

Which you choose will depend on they type of turfgrass you have, as well as local regulations.

They're the only chemicals I know of, other than glyphosate, but you well know that using that requires reestablishment of the turfgrass after the app.

Best of luck to you,

[Kate]

I live in the desert, and drainage is not a problem. I may tend to over water when it is in the 90 - 102 degree temps that we get about two weeks out of the summer, and that could be a problem. I will try to watch it better this summer.

Many thanks for taking the time to email, and I appreciate your help.

Kate