Grassy Weed Seed Head Identification

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Grassy weeds are true grasses or monocots. A grass seed germinates and emerges as one single leaf. It develops hollow, rounded stems and nodes (joints)… Annual grassy weeds are some of the more frustrating lawn weeds homeowners will encounter. Learn how to identify different types of grassy weeds and keep your lawn in great shape year round with TruGreen®.

Grassy Weeds

Grassy weeds are true grasses or monocots. A grass seed germinates and emerges as one single leaf. It develops hollow, rounded stems and nodes (joints) that are closed and hard. The leaf blades alternate on each side of the stem, are much longer than they are wide and have parallel veins.

A weed’s life cycle has great impact on the selection and success of a given control procedure, so it is important to learn the life cycle characteristics of a weed when you first learn its identity.

Annual weeds germinate from seeds, grow, flower, produce seeds and die in 12 months or less. Annual weeds are further categorized by the season in which they germinate and flourish. Winter annuals sprout in the fall, thrive during the winter and die in late spring or early summer. Summer or warm-season grasses such as crabgrass and goosegrass sprout in the spring and thrive in summer and early fall.

Perennial weeds are weeds that live more than two years. They reproduce from vegetative (non-seed) parts such as tubers, bulbs, rhizomes (underground stems) or stolons (above-ground stems), although some also produce seed. Perennial weeds are the most difficult to control because of their great reproductive potential and persistence.

Proper identification of weeds targeted for control is necessary in order to select effective control measures, whether cultural or chemical. Further assistance with weed identification is available from any Clemson Extension office.

Annual Bluegrass

Life Cycle & Description: Annual bluegrass (Poa annua) is a winter annual weed that emerges in early fall, persists through the winter, produces seed in early spring and then dies in late spring or early summer. Annual bluegrass reproduces by seed.

Annual bluegrass (Poa annua) is a cool weather annual grass weed that produces seed heads in the early spring.
Joey Williamson, ©2015 HGIC, Clemson Extension

Annual bluegrass prefers shady, moist sites and invades weak, thin lawn areas, especially low spots and flower beds where standing water occurs. It mainly germinates in late summer through early fall when nighttime air temperatures drop to the mid-70s. This usually occurs from September 15 to October 1 in the Coastal Plain and Sandhills areas, and September 1 to 15 in the Piedmont and Mountain areas. Further germination occurs in early winter with warm days and cold nights.

Annual bluegrass produces a white-colored, pyramid-shaped seedhead in the spring. It dies in the summer with the onset of high temperatures and/or dry conditions.

Annual bluegrass has smooth, apple-green leaves with two clear lines, one on each side of the midrib that run down the length of the leaf blade. The edges of the leaf tip curve inward like the front of a boat.

Control: Handpulling is a simple, practical approach for small areas. Improve the health and density of the lawn by fertilizing at the right time and with the correct amount; maintaining an appropriate soil pH; mowing at the recommended height; and watering properly. Apply a 2- to 3-inch layer of mulch to ornamental bed areas to suppress germinating weed seeds. Finally, improve surface drainage. Preemergence herbicides are available depending on the kind of turfgrass and ornamental plants grown. Apply preemergence herbicides to established lawns before the annual bluegrass seeds germinate. Once annual bluegrass emerges, preemergence herbicides are generally ineffective.

Selective postemergence herbicides are available for annual bluegrass control. These are best applied in November or early December when the weed is small, thus most susceptible to control. See Tables 1 & 2 for pre-emergence and post-emergence control. Apply all chemicals according to directions on the label.

Crabgrass & Goosegrass

Life Cycle & Description: Crabgrasses (Digitaria species) are summer annuals that germinate in the spring at about the time crabapple and forsythia bloom, when the air temperature is warm enough to promote crabgrass seed germination. They produce seed from midsummer to fall and are then killed by the first freeze in autumn. Crabgrass reproduces by seed.

Crabgrass can be identified by its tufted or prostrate growth habit, hairy stems, broad leaves and flower spikes with two to nine finger-like branches. This weed appears in disturbed areas, weak or thin turf areas and in edges of the lawn next to sidewalks and drives.

Goosegrass (Eleusine indica) is a tough, clump-forming summer annual with white to silver coloring near its base. Unlike crabgrass, goosegrass has flat stems and does not root at the lower nodes. It germinates a few weeks after crabgrass in late spring and produces seed from summer to early fall. The flowers and seeds are produced in two rows like a zipper on two to 13 finger-like branches at the top of the stem. Goosegrass is killed at the first freeze, and reproduces entirely from seed.

Goosegrass (Eleusine indica) can be identified by the white to silver color near the base of the grass clump.
Joey Williamson, ©2015 HGIC, Clemson Extension

Control: Handpulling is a simple, practical approach for small areas. Improve the health and density of the lawn by fertilizing at the right time and with the correct amount; reducing soil compaction; maintaining an appropriate soil pH; mowing at the recommended height; and watering properly. Apply a 2- to 3-inch layer of mulch to ornamental bed areas to suppress germinating weed seeds.

Preemergence and postemergence herbicides are available depending on the kind of turfgrass in your lawn. Preemergence herbicides provide about 2 to 2 1/4 months of control. Repeat applications would be required 60 days later for season-long control. Apply preemergence herbicides March 1 from the Coastal Plain to the Sandhills regions, and March 15 to 30 in the Piedmont and Mountain areas. Fall-seeded turfgrasses should not be treated with a preemergence herbicide until the following spring. See Tables 1 & 2 for pre-emergence and post-emergence control. Apply all chemicals according to directions on the label.

Sandbur

Life Cycle & Description: Southern sandbur, or sandspur (Cenchrus eschinatus), and field or coast sandspur (Cenchrus incertus) are summer annuals that germinate in the spring, grow during the summer and early fall and die with the first heavy frost. The name “sandspur” describes the sandpapery feel of their leaves and the spurs or burs that are produced from July until the first frost. Both reproduce by seeds. Sandspur tends to be more of a problem on sandy soils from the Coastal Plain westward to the Sandhills.

Control: Handpulling with gloved hands is a simple, practical approach to control sandspur in small areas. Improve the health and density of the lawn by fertilizing at the right time and with the correct amount; maintaining an appropriate soil pH; mowing at the recommended height; and watering properly. Apply a 2- to 3-inch layer of mulch to ornamental bed areas to suppress germinating weed seeds.

This annual weed can be controlled with a preemergence herbicide applied in early spring (March 1 in the Coastal areas to March 15 in Piedmont areas). Repeat in 60 days. Select an herbicide that can be safely used on your lawn.

See Tables 1 & 2 for pre-emergence and post-emergence control. Apply all chemicals according to directions on the label.

Table 1. Pre-emergence Herbicides to Prevent Grassy Weeds in Residential Lawns.

Weeds Prevented Active Ingredients Examples of Brands & Products
Annual grass weeds including crabgrass & annual bluegrass benefin Pennington
Crabgrass
Preventer
Same as for benefin, plus goosegrass oryzalin Southern Ag Surflan A.S. (40.4%)
Same as above benefin + oryzalin Helena XL2G (1% & 1%)
UPI Surflan [email protected] (1% & 1%)
Green Light Amaze Grass & Weed Preventer (1% & 1%)
Summer annual grasses, annual bluegrass, some selected annual broadleaf weeds benefin + trifluralin Anderson Turf Products 2% Team Herbicide DG (1.33% &0.67%)
Hi-Yield Crabgrass Control
Same as for benefin, plus oxalis & speedwell pendimethalin Anderson Turf Products 1.71% Pendimethal in DG
Scotts Halts Crabgrass & Grassy Weed
Preventer (1.71%)
Harrell’s 0-0-10 with 0.86% Pendimethalin
Same as for benefin, plus oxalis dithiopyr Anderson Turf Products 0.25% Pendimethal in DG
Bonide Crabgrass & Weed Preventer for Lawns & Ornamental Beds (0.27%)
Hi Yield Turf & Ornamental Weed & Grass Stopper Containing Dimension (0.125%)
StaGreen CrabEx Crabgrass & Weed Preventer (0.25%)
summer annual grasses, annual bluegrass, some selected weeds such as chickweed, spurge, goosegrass prodiamine Helena Pro-Mate Barricade & Fertilizer 0-0-7 (available with 0.22, 0.375, or 0.435%)
Howard Johnson Crabgrass Control with Prodiamine & 0-0-7 (0.86%)
Lebanon Pro Fertilizer (0-0-7) with Prodiamine (0.38% or 0.43%)
Lesco Stonewall Plus Fertilizer (0-0-7) (available with 0.20, 0.29, 0.37, or 0.43%)
Lesco Barricade Plus Fertilizer 0-0-7 (0.43%)
Scotts Halts Pro 0-0-7 & Halts Pro (0.28%)
Harrell’s 0-0-7 with 0.21% Barricade
Harrell’s 0-0-7 with 0.30% Barricade
Harrell’s 0-0-7 with 0.45% Barricade
Southern States Pro Turf 0-0-7 with 0.38% Barricade

Table 2. Post-emergence Herbicides to Control Existing Grassy Weeds in Residential Lawns.

Weeds Controlled Active Ingredients Examples of Brands & Products
annual & perennial grasses, such as crabgrass, foxtails, goosegrass, sandbur; bermudagrass suppression fenoxaprop
(for fescue lawns only)
Aventis Acclaim Extra
Bayer Advanced Crabgrass Concentrate (6.59%) Killer for Lawns RTS (0.41%)
annual & perennial grasses control. Excellent control of crabgrass; good control of bermudagrass, sandspur, bahiagrass & goosegrass sethoxydim
(for centipedegrass lawns only)
Arrest (by Whitehall Institute) (13%)
Segment (by BASF) (13%)
Excellent control of crabgrass; fair control of dallisgrass, foxtails, & signalgrass. Also, most broadleaf weeds, such as dollarweed, black medic, wild onion & garlic, speedwells, plantains, dandelion, white clover, violets, henbit, chickweed, star of Bethlehem quinclorac + 2,4-D + dicamba (for fescue, zoysiagrass, & bermudagrass 1 ) Bayer Advanced All-in-One Lawn Weed & Crabgrass Killer Concentrate
Bonide Weed Beater Plus Crabgrass & Broadleaf Weed Killer RTS
Ferti-lome Weed Out with Crabgrass Control RTS
Monterey Crab-E-Rad Plus RTS
Ortho Weed B Gon Max Plus Crabgrass
Control RTS
Excellent control of crabgrass; fair control of dallisgrass, foxtails, & signalgrass. Also most broadleaf weeds, such as dollarweed, black medic, speedwells, plantains, dandelion, white clover, violets, henbit, chickweed, star of Bethlehem, & nutsedges. quinclorac + 2,4-D +
dicamba + sulfentrazone
(for fescue, zoysiagrass & bermudagrass 1 )
Spectracide Weed Stop for Lawns Plus
Crabgrass Killer RTS
Excellent control of crabgrass; fair control of dallisgrass, foxtails, & signalgrass; Also, some broadleaf weeds, such as dollarweed, black medic, violets, speedwells, dandelion, white clover, nutsedges, chickweed, star of Bethlehem, & henbit. quinclorac + sulfentrazone
(for fescue, zoysiagrass & bermudagrass 1 )
Image Kills Crabgrass – Water Dissolving Granules
Very good control of annual bluegrass; fair control of crabgrass, sandspur, bahiagrass, fescue, & bermudagrass; poor control of goosegrass, & dallisgrass. Also many broadleaf weeds. atrazine (for St. Augustinegrass & centipedegrass) Hi-Yield Atrazine Weed Killer (4.0%) Concentrate
Southern Ag Atrazine St. Augustine Weed Killer (4.0%) Concentrate
Image Herbicide for St. Augustine &
Centipede with Atrazine RTS (4.0%)
Annual & perennial grass control, including bermudagrass, crabgrass, foxtail, goosegrass, torpedograss, johnsongrass fluazifop-
P-butyl (for Tall Fescue & Zoysiagrass
Gordon’s Ornamec 170 Grass Herbicide (1.7%)
1 Products containing quinclorac may cause temporary yellowing or discoloration of bermudagrass.
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Pesticides are updated annually. Last updates were done on 7/22 by Barbara Smith.

Originally published 09/99

If this document didn’t answer your questions, please contact HGIC at [email protected] or 1-888-656-9988.

Author(s)

Robert F. Polomski, PhD, Associate Extension Specialist, Clemson University
Bert McCarty, PhD, Turf Specialist, Clemson University

This information is supplied with the understanding that no discrimination is intended and no endorsement of brand names or registered trademarks by the Clemson University Cooperative Extension Service is implied, nor is any discrimination intended by the exclusion of products or manufacturers not named. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.

Annual Grassy Weeds
Identification and Control
– Crabgrass and Foxtail Weeds –

Let’s look first at crabgrass. Most grassy weeds are undesirable weedy grasses that germinate and grow in lawns, but can lower turf quality and appearance. These weeds do not have the characteristics or growth habits that produce a quality lawn.

Annual grass-type weeds are those that germinate from seed each year and die at the end of the growing season. Annual weeds are prolific seed producers since seed germination is the method of producing the next year’s generation of plants.

Crabgrass (Late Spring Annual Weed)

  • One of the most common and troubling grassy weeds.
  • Yellow-green to a darker blue-green in color.
  • Can be prostrate or upright growing.
  • Multi-branched stems. Large crabgrass roots at the nodes.
  • One plant can produce over 150,000 seeds.
  • It doesn’t make a good lawn because it doesn’t take off until late spring or early summer and dies with the first heavy frost.
  • Plants start off sparse but increase in number and size by end of the year.
  • Can be difficult to stop once they start growing.

Weed Identification

The U.S. and Canada have many grassy weeds with crabgrass being one the most problematic. There are two major species of crabgrass: smooth crabgrass (also called small crabgrass) and large crabgrass (also called hairy or common crabgrass). Smooth crabgrass is found mostly in the northern half of the U.S. and large crabgrass is found throughout the U.S. and southern Canada.

All crabgrass varieties are summer annuals that must come back each year by seed. It is a full sun grassy weed and will only tolerate very light, partial shade. It will not grow in shaded areas.

Crabgrass was originally introduced into this country as a possible forage crop. However, it easily escaped cultivation and is now widespread throughout the country. It is one of the most common and problematic weedy grasses in home lawns. It is also found on golf courses, parks, flower and vegetable gardens, athletic fields and any other place that seeds are able to germinate.

Crabgrass is most at home in areas of thin or poor quality turf. The plants grow quickly and can cover an entire yard by the end of summer.

Crabgrass is yellow-green in color with short, wide leaves. While the seedling look similar to other plants, they soon begin to distinguish themselves. In young plants, like the one in the photo to the left, the leaves are twice as long as they are wide. These young plants begin by growing prostrate with three or four stems branching out in a starfish pattern. As the plant matures the stems will curve in an upward direction. Each plant can produce as many as 700 new tillers (new leaf blades). At full maturity, each leaf will grow to be a few inches long. Crabgrass leaves have tiny hairs on both sides of the leaves.

The roots are shallow and fibrous and do not reach the depth of many other grasses. Large (hairy) crabgrass will root at the nodes and can produce long stolons. Smooth crabgrass does not root at the nodes.

The shallow root system works in their favor by absorbing as much water as possible before it reaches the deeper rooted plants. Frequent, shallow watering will cause crabgrass to flourish at the expense of other grasses. Less frequent, deep watering is better for your turfgrass, but will not neccessarily hinder crabgrass growth.

The photo above is of a mature crabgrass plant, while the photo below is of common bermudagrass.

The leaves of bermudagrass are much finer and are darker in color. Crabgrass seed heads are finger-like spikes that resemble common bermudagrass seed heads. However, crabgrass seed heads are somewhat thicker.

There are usually three to seven spikes that can either be folded up like a funnel or spread out in a whorl pattern. Each plant can produce as much as 150,000 seeds a year. Crabgrass germinates from seed each year when soil temperatures reach 55 degrees for five consecutive days. The blooming of forsythia in your area closely coincides with the germination of crabgrass seeds.

Once the seed has germinated, crabgrass becomes difficult to control. Because of the prostrate growth habit, crabgrass can produce seed heads at mowing heights as low as ½ inch. Mowing your lawn at a height lower than is healthy for your particular grass will only benefit and encourage crabgrass growth.

Cultural Practices that Help Prevent Grassy Weeds

Cultural Practices

Crabgrass, like many there grassy weeds, do not like competition from turfgrass. Crabgrass grows best in poor quality lawns, lawns cut and maintained too short, lawns with disease or insects damage, and in high traffic areas. Lawns with thin or deteriorating grass will give the seed plenty of sun, heat and space for seed germination. A poorly maintained lawn will guarantee that you will have increasing problems with broadleaf and grassy weeds.

If crabgrass is a problem, avoid fertilizing in late spring and summer. Especially avoid applications of high Phosphorus fertilizers. Phosphorus is essential for seedling growth and will only promote crabgrass establishment.

The best method of keeping crabgrass and other grassy weeds out of your lawn is to build a thick, healthy, vigorously growing turf. The first step is to ensure you have the right grass type for your area. Increasing the grass thickness can be accomplished by overseeding, plugging or laying sod, proper fertilization and irrigation. Until the lawn thickens, grassy weeds will continue to be a problem.

It is also important to mow your lawn at the highest recommend level for your specific grass type. This will shade the soil and make germination more difficult. Many cool season turf grasses can be mowed at a height of 3 to 4 inches. Depending on your grass type, see the Cool Season Grasses or the Warm Season Grasses Warm Season Grasses sections of this site for helpful mowing and planting information.

You may find it necessary to use a preemergent herbicide to prevent the seeds grassy weeds and other weeds from germinating.

Herbicide Use

The most effective and proven method of preventing crabgrass from starting is to use a preemergent herbicide. I can’t stress this enough. If you want to prevent crabgrass from ever starting, you have to use a preemergent.

Preemergents are an added ingredient in many spring fertilizer. The bags will be labeled “with Crabgrass Control” or “Crabgrass Preventer”, etc. Make sure you spread the fertilizer at the correct nitrogen (N) level for your grass type. For help developing a sound fertilizer program, read the page on Developing a Fertilizer Program.

A preemergent must be applied before the crabgrass seeds germinate in spring. Again, it MUST be applied before they germinate with only one exception, the use of Dimension preemergent will kill the crabgrass at very early seedling stages. I will describe this in better detail below.

A preemergent (also spelled pre-emergent or pre-emergence) herbicide works by preventing cell division on young plants. A preemergent doesn’t actually prevent the seeds from germinating, as commonly believed. However, once the seeds do germinate, the chemical prevents the cells from dividing and the seed dies. In this way, the seeds are destroyed. An important note: Preemergents will have the same effect on most lawn grass seeds as well. Do not overseed directly before or within a few months after herbicide application or your seed may be ruined.

If you have waited too long and the crabgrass begins growing, preemergents usually have no effect. However, there is one product with the trade name “Dimension” (Chemical name: dithiopyr) that will give some control of seedling plants for a few weeks after emerging from the soil.

The effectiveness of some homeowner type preemergent herbicides is questionable. Some brands don’t perform as well as others. The effectiveness is also related to how it was applied, the amount and frequency of irrigation, amount of rain received, etc.

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Keep in mind, if applied too early, the chemical can breakdown too soon allowing mid to late season seeds to germinate. Other chemicals have a short life span and it must be reapplied in mid-summer. Therefore, timing of the application is very important. Outside temperature and soil temperature are important. Remember, crabgrass germinates when soil temperatures reach 55 degrees for five days in the top inch of soil. It is okay to water after the preemergent has been put down, but don’t over water or water too frequently. Frequent, heavy irrigation or heavy rain places maximum stress on these herbicides.

For Established Weeds

Once the weeds are established, they are very difficult to control. Post-emergent herbicides labeled for grassy weeds will need to be used. Most products will require several applications for complete control. Products with MSMA or DSMA will control crabgrass as well as other weedy grasses. The Ortho company makes a product with these active ingredients. Add the correct amount of a “sticker/spreader” to the herbicide mixture for better adherence and absorption into the plant.

There is also the herbicide quinclorac under the trade name “Drive”. This is now available to homeowners and sold by Ortho under the name “Weed-B-Gon MAX Plus Crabgrass Control Ready To Use”. It contains other ingredients to help control broadleaf weeds as well.

Organic Preemergent

The most popular preemergent for crabgrass and other grassy weeds is Corn Gluten Meal. Nick Christians, a turf specialist and university professor in Iowa, holds the patent.

Corn Gluten Meal is sometimes marketed as an organic weed killer for broadleaf and grassy weeds. Although it actually holds little or no weed killing properties it is, however, an effective preemergent. It works by robbing the moisture from developing germinated seeds and seedlings.

One main difference between chemical preemergents and corn gluten meal is the amount applied. Corn gluten meal must be applied between 10 to 30 lbs 1000/sq.ft. Generally, 20 lbs/1000 sq. ft. is the average for most lawns. Use more for severe weed problems. It does not require a license to use.

Timing is important and it must go down near the time that seeds will germinate. After application, irrigate the corn gluten and allow a drying period. This is critical for effectiveness because it must absorb the surface moisture. In wet climates, such as the north western U.S., corn gluten meal may not be as effective. A second application can be made in the fall.

Keep in mind, with corn being used as fuel for vehicles, corn gluten meal is rising in cost. Shop for the best price.

Final Notes

Learn From the Mistakes of Others: Spraying your lawn with a a non-selective herbicide such as Round-up, etc is not an effective crabgrass control. It doesn’t harm the seeds in the soil. Although it will kill all the grass and weeds it touches, the following year you will still have the problem with crabgrass and other broadleaf and grassy weeds that start from seed.

For lawns containing 50% or more weeds with thin or very little grass, a non-selective herbicide can be used if you plan on seeding or sodding soon after. Don’t wait too long to renovate or the weeds will become established and you will have to do it again. Each grass type has a preferred time of year when it should be planted.

Read labels carefully and follow all label instructions. Note that MSMA and DSMA are not recommended for St. Augustinegrass, centipedegrass or carpetgrass.

Yellow and Green Foxtails (Summer Annual Weed)

Foxtails are a summer annual grassy weed. They get their name from the seedhead that resembles a fox’s tail. They can spread quickly in sunny areas but less so in shade. The same preemergents that control crabgrass will also control foxtails.

  • Grassy weeds with characteristic cylindrical seed heads.
  • Yellowish-green to blue-green leaves.
  • Seed heads are 2-3 inch.
  • Reproduces from seed only.
  • Difficult to control once seeds have germinated.
  • You will start to see foxtails as soon as the crabgrass weeds are well-established.
  • The same preemergent that stops crabgrass also stops foxtails.

Weed Identification

Foxtails are a species of warm season, annual grassy weeds that starts from seed. It grows in full sun, but can tolerate very light, partial shade. It will not grow in shaded areas.

It develops from a fibrous root system and has a prostrate to upright growth habit. With mature plants, it is common to see the stems branching out at the base, remain prostrate for an inch or two and then curve upward at a 30 to 70 degree angle. Each plant can produce multiple stems that can easily grow twice the height of the leaves.

The coarse leaves are a yellowish-green to a darker blue-green color. They can grow to 12 inches long and up to ½ inch wide. The leaves are flat and smooth. The widest part of the blade is at the base. The leaves have small silky hairs on the upper surface near the base.

Foxtails are known for their characteristic seed head that has a foxtail-like appearance. The seed head is at the end of the stalk and usually extends several inches above the leaves. Mature plant can have a dozen or more seed heads and can produce thousands of seeds each year. Seeds germinate when temperatures reach 68 degrees and will continue germinating through most of the summer. Foxtails will die at the first killing frost.

Giant foxtail is another foxtail species that grows 2-5 ft tall, but it cannot take repeated mowing. For this reason, giant foxtail is rarely found in mowed turf. Notice that the seed head of giant foxtail droops, while yellow and green foxtail seed heads do not.

Cultural Practices

The primary way of preventing the establishment and spread of foxtail is to maintain a thick, healthy lawn. Maintaining your lawn at the tallest mowing height recommended for your grass type will help slow seed germination.

Consistent, weekly mowing to remove the seed heads before they mature will also go a long way to deter spread. If you have only a few plants growing in your lawn, try removing them by pulling them up. The plant has a fibrous root system, however, some plants will root at the nodes near the base of the plant.

Herbicide Use

If you have had problems before with foxtails, the best way to stop their development is with a preemergent herbicide. These preemergents are added to spring fertilzers.

The same herbicides labeled for crabgrass will work on many other grassy weeds, including foxtails. Preemergents are added to spring fertilizer and will be labeled “with Crabgrass Control” or “Crabgrass Preventer”, etc. Always check the label before using, however. Once the preemergent had been applied, moisture in the soil will activate it. Fertilizers need to be applied correctly in the amounts needed for your grass type and time of year. Scotts fertilizer brand as well as a few others are good homeowner fertilizers. Bargain brands may not give you the control over grassy weeds that you would like. Since fertilizer applicatons are based on the Nitrogen (N) needs of the grass you will need to know how much to apply. Click on the link for helpful information on Developing a Fertilizer Program.

Most preemergents are designed to last a few months before they begin to lose effectiveness. Not all active ingredients work equally well or have the same duration and homeowner varieties tend to last the least amount of time. This means that your timing will be very important. Important Note: Foxtails will germinate a few weeks to a month later than crabgrass. Something to remember when applying a preemgerent.

Once the seed germinates, the herbicide chemical stops cell division within the seed, so the plant never develops. As a result, the seed dies.

The preemergent herbicide label may list other broadleaf and grassy weeds that it controls. However, most are not very effective with broadleaf weed seeds.

For Established Weeds

Post-emergence herbicides will be needed once the foxtails have become established. The herbicides containing the active ingredients MSMA or MSDA are labeled for many grassy weeds, including foxtails. Read the label carefully and follow all label instructions. MSMA and DSMA are not recommended for use on St. Augustinegrass, centipedegrass or carpetgrass.

There is also the herbicide quinclorac under the trade name “Drive”. This is now available to homeowners and sold by Ortho under the name “Weed-B-Gon MAX Plus Crabgrass/Grassy Weeds Control. It is a “Ready To Use” formulation, meaning it comes already pre-mixed. It contains other ingredients including 2,4-D and Dicamba to help control broadleaf weeds as well.

Nimblewill Grassy Weed
Nimblewill is a grassy weed that resembles bermudagrass. It is most prominent when growing in cool season grasses. Find information on identification, growth habits, and control methods.

Winter Annual Broadleaf Weeds
With each spring comes a surge of winter annual broadleaf weeds. Here you will find valuable information about these difficult weeds including growth habits, photos, and measures that can be taken to control them.

Summer Annual Broadleaf Weeds
Many of the most problematic broadleaf weeds are annuals. Here you will find specific summer annual weed information, with weed names, photos and control methods.

Perennial Broadleaf Weed Identification Page 1
Click here for weed identification and control of common broadleaf perennial lawn weeds. This page has detailed information on Canada Thistle, Mouseear Chickweed, White clover, Dandelion, Field Bindweed, Ground Ivy, and Common Mallow.

Perennial Broadleaf Weed Identification Page 2
This page contains more perennial broadleaf weed identification and control methods. You can find detailed information on Buckhorn Plantain, Broadleaf Plantain, Red Sorrel, Wild Violets, and Common Yarrow.

Yellow and Purple Nutsedge
Nutsedge is a summer perennial grass-like weed. They can be particular problematic since they cannot be controlled by broadleaf weed herbicides. Click here for weed identification, growth habits and control methods.

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Grassy Weeds

To the untrained eye, distinguishing turf grass from grassy weeds is tough because the two can look identical. But with practice and persistence, you can learn to identify lawn weeds—and even the difference between grass and sedge—by inspecting the primary vegetative characteristics of your lawn.

Here are some of the features our TruGreen® experts use to weed out the bad grasses.

  • Crown. The white, thick part of the grass plant at soil level where the shoot meets the roots. It’s central to lawn health—if the crown dies, the grass plant dies.
  • Sheath. The lower (basal) portion of the grass leaf between the crown and the blade that encloses and protects young shoots of grass. Sheath margins may be split, split with overlapping margins or be closed.
  • Collar. The backside of a leaf where the blade and sheath join. Collars may be divided by a line that runs up the center (mid-rib) or be continuous. Collar shapes vary from narrow to broad and can have slanted or straight borders.
  • Blade. The section of the leaf above the collar. Characteristics to look for include the type of tip, roughness or smoothness, and mid-rib.
  • Vernation. The leaf arrangement of the youngest leaf (called the budleaf) and its surrounding sheath. Look to see if the budleaf is rolled or folded.
  • Ligule. A tip- or cylinder-shaped structure poking out from the top half of a leaf where the blade and the sheath join. Ligules can be membranous, hairy, both or absent altogether, making them useful for spotting grassy weeds in grass.
  • Auricle. A pair of appendages sticking out from the side of the grass leaf where the sheath and blade meet. Auricles can be short and stubby, large and claw-like, have short hairs attached or be absent, also making them useful grass identifiers.
  • Rhizomes. An underground stem that produces a new plant.
  • Stolons. A horizontal, above-ground stem that roots at the nodes (found in the crown) and gives rise to new grass plants.
  • Seed head. The flowering or seeding parts found at the top of the grass plant. Check if seed heads are spike or panicle to help with turf grass identification.

Life Cycle

An essential part of identifying grassy weeds has to do with their life cycles. For example, you may be able to hand-pull a few annual weeds to enjoy a weed-free backyard cookout, but perennial grassy weeds have a deeper root structure that can give rise to new weeds—even if you no longer see the weeds in your lawn. Learn what the different life cycles of lawn weeds mean for your control plan.

Annual weeds. These weeds live for only one season and are typically easy to control because they lack the complex underground structures needed to spread new plant growth through creeping roots. Still, annuals produce tons of seeds that can infest and dominate your yard under the right conditions.

Summer annuals. These grass-like weeds begin to grow (germinate) in the spring, mature in the summer, and then produce seeds and die by the fall or first hard frost—an entire life cycle completed within 12 months.

Winter annuals. These weeds overlap two calendar years but last only 12 months total. They germinate and develop from late summer to early fall, remain semidormant during the winter and then flower in spring. Come late spring or early summer, they mature and die off as the weather warms.

Perennial weeds. Perennial grassy weeds can germinate and spread from seeds, but they also produce a root structure (tubers, bulbs or corms) that can birth new weeds from your lawn’s surface (using stolons) or from underground (using rhizomes).

Biennial weeds. These flowering plants generally live for two years. The first year consists of leaves, stems and root growth, followed by winter dormancy. In the second year, biennials flower and produce seeds, thus completing their life cycles.

Control

Without a professional service, removing grass-like weeds without damaging your lawn is difficult. The biological similarities of turf grass and grassy weeds make both susceptible to control methods. For example, spraying crabgrass killer at the wrong time can kill your grass seeds. Instead, aim to control grassy weeds by keeping your lawn dense and healthy so they don’t stand a chance. If these turf grass imposters have already invaded your lawn, you can try a few other tactics to weed them out.

What’s the Best Weed Control?

The most effective weed control is a flourishing lawn because it’s more competitive and will crowd out grassy weeds. Weed seeds need light to grow, which a dense lawn blocks out. To keep your lawn lush, healthy and competitive, try:

  1. Fertilization. The right type and application method makes all the difference.
  2. Mowing. Mow frequently at the recommended height with sharpened blades, removing only one-third of the leaf blade.
  3. Watering. Water deeper rather than more frequently when rainfall is scarce.
  4. Changing. Factor in climate, sunlight, shade, etc., to pick the right turf grass. [Links to J.5 Turf Grass Selection Module]
Does Pulling Weeds Work?

Hand-pulling grassy weeds can work if there are only a few, especially if they’re annuals. Perennial grassy weeds are harder to control by hand because you don’t always pull up the vegetative structure, which is what sprouts new weeds.

What Type of Crabgrass Killer Won’t Harm My Lawn?

Postemergence herbicides control existing weeds. Unfortunately, because grassy weeds are in the same family as turf grass, these types of herbicides can also harm your lawn. Preemergence herbicides control seeds only—not existing weeds—making them safer for an established lawn (grass seeds are susceptible). They work on most seed-based annuals and perennials.

Because each yard is unique, TruGreen® customizes a grassy weed control program for your lawn. The plan of attack depends on your region, type of turf grass and the specific weeds invading your lawn.

Identify

To the untrained eye, distinguishing turf grass from grassy weeds is tough because the two can look identical. But with practice and persistence, you can learn to identify lawn weeds—and even the difference between grass and sedge—by inspecting the primary vegetative characteristics of your lawn.

Life Cycle

An essential part of identifying grassy weeds has to do with their life cycles. For example, you may be able to hand-pull a few annual weeds to enjoy a weed-free backyard cookout, but perennial grassy weeds have a deeper root structure that can give rise to new weeds—even if you no longer see the weeds in your lawn. Learn what the different life cycles of lawn weeds mean for your control plan.

Control

Without a professional service, removing grass-like weeds without damaging your lawn is difficult. The biological similarities of turf grass and grassy weeds make both susceptible to control methods. For example, spraying crabgrass killer at the wrong time can kill your grass seeds. Instead, aim to control grassy weeds by keeping your lawn dense and healthy so they don’t stand a chance. If these turf grass imposters have already invaded your lawn, you can try a few other tactics to weed them out.

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