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light green weed growing in lawn #268214

Asked August 06, 2015, 9:53 PM EDT

Hi, I live in York and I (and some of my neighbors) have light yellowish-green weeds growing in my lawn. They grow very quickly compared to my grass and have multiple blades that come up from the root. I can provide a picture if necessary. I was hoping for some direction as to how to get rid of these, if not for this year but for next. Thanks!

York County Pennsylvania

Expert Response

We need pictures to identify the weed. If you use herbicides, there are broad leaf weed killers on the market and sold at garden centers. There are also some herbicides that specialize in crabgrass for example.
Tending to lawn weeds without chemicals is a longer process. You need to cut your lawn grass no shorter than three inches. Before you mow, remove weeds that are in flower or going to seed so you don't spread weed seeds around your lawn. The mowing height gives the grass a chance to shade out emerging weed plants.
Then the most important steps are listed in an article from Penn State.

Penn State publishes a fact sheet called Lawn Management Through the Seasons that explains how to create a healthy lawn.
An Ask Extension Expert Replied August 07, 2015, 10:25 AM EDT
Thanks...here are the pictures. The tall lighter colored blades are the weed in question. I also pulled one. Also, in the Spring I treaded my lawn with Scotts with Crabgrass Preventer, then in May (I think) with Scotts with Weed Control.
The Question Asker Replied August 07, 2015, 7:04 PM EDT
That looks like annual rye grass. It germinates from seed each year and probably germinated after you applied your weed killer.
An Ask Extension Expert Replied August 08, 2015, 9:32 AM EDT
Thanks again. What would you recommend to keep the annual rye grass from coming up next year? I want to get rid of it since it grows so much taller than my other grass so it looks like weeds in my lawn.
The Question Asker Replied August 08, 2015, 12:31 PM EDT
You can look at the garden center for an herbicide that targets rye grass. Since it is an annual, a pre-emergence herbicide applied in early spring will stop most of the seeds from germinating. At this time of year, you either have to apply a selective herbicide per directions on the package, or use a mechanical means of killing the weeds.
 Getting rid of weeds in a lawn is an ongoing process on two fronts. You need to encourage the good grass to grow thick with long roots by following a plan of feeding and watering, and you need to keep after the things you don't want because they will keep trying to come back. Any bare patch is a place for weeds to get started.
 In my garden, I use a propane torch I bought at a garden center. It is made for killing weeds. I walk around and burn the top growth off weeds. If you search "weed torch" you will see what it is. The weed can only regrow so many times before the roots are exhausted and die.
An Ask Extension Expert Replied August 08, 2015, 8:14 PM EDT

It is a little difficult to see from the photo, but I believe the weed in your lawn is actually yellow nutsedge not annual ryegrass.  Yellow nutsedge, also known as yellow nutgrass, is a warm season perennial in the sedge family. Sedges look like grasses, but if you roll the stem of sedges between your fingers you will notice they are three sided. Grass stems are round or flattened.

Nutsedge is often considered troublesome when it appears in lawns. It is a lighter green and grows faster in hot weather than our lawn grass.

Nutsedge has upright, light yellow-green leaves 1/8 to 1/2 inch wide and up to three feet long. They have parallel veins with a prominent midvein. Leaves grow rapidly in summer often appearing well above the lawn grass. Nutsedge has a fibrous root system. It also develops horizontal underground stems (rhizomes) with white tubers (nutlets) forming on the ends of the rhizomes.

Tubers develop rapidly six to eight weeks after the plants emerge usually during late July and August. Nutlets may get to be almost an inch in diameter. Unfortunately the nutlets may persist in the soil for many years. New plants emerge from the nutlets from late May to mid-July.

Yellow nutsedge is often an indicator of poor drainage. It particularly likes wet or moist sites or sites heavily irrigated. However it can grow in all soil types and can tolerate dry sites once it's established.

Yellow nutsedge is difficult to control especially once it has formed tubers. If you want to control it, don't wait. Once it has formed tubers, pulling it out will only remove the original plant.

To control nutsedge without chemicals, maintain a thick stand of lawn grass through proper maintenance.  Pull nutsedge plants soon after emergence before nutlets can form. Modify drainage in moist or wet areas. Check for nutlets in purchased soil or mulch.

If herbicides are chosen as the control option, there are several available to be used in lawns once the nutsedge emerges. However herbicides often will not give total control and multiple applications may be necessary. Herbicides for nutsedge control are generally applied from mid-summer to mid-fall.   Ortho as well as other companies make a crabgrass and nutgrass killer. Always read, understand and follow the label directions.


An Ask Extension Expert Replied August 08, 2015, 8:58 PM EDT

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