Grassy Weed Seed Head Identification Crabgrass is one of the most common warm season annual grassy weeds. The stems grow mostly prostrate, branch freely, and send down roots where each joint 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)… Differentiating weeds from grass is important to treat the issue. How can you tell the difference?
Grassy Weed Seed Head Identification
Crabgrass is one of the most common warm season annual grassy weeds. The stems grow mostly prostrate, branch freely, and send down roots where each joint comes into contact with the soil or moist grass. The sead head is divided into several fingerlike segments. Two principal species are (1) large crabgrass, sometimes known as hairy crabgrass and (2) smooth crabgrass. Smooth crabgrass tends to be smaller, less hairy, and has purplish color on the stems.
A cool season perennial wheatgrass that speads extensively by long white rhizomes (underground stems.) Leafblades are twice the width of bluegrass and tend to be rough in texture. A claw-like protrusion of the leaf called an auricle clasps the stem. One of the most distinguishing characteristrics is a ring of root hairs every 3/4 to 1 inch along the rhizomes. The lower leaf sheath of the stem is hairy.
Cool season perennials common throughout the region. The yellow flowers occur from early spring to late fall. The thick fleshy taproot, often branched, can give rise to new shoots. Seedlings may appear throughout the spring and summer and are often abundant in the fall.
A very coarse cool season perennial bunch grass. Scattered clumps objectionable in fine textured turf grasses. Leaf veins are strongly fibrous. When mowed, fibers show on the cut edge, especially if mower blades are not well sharpened. Mature leaf blades may be one-half inch wide, ribbed above and shiny smooth below. The lower portions of the steams are reddish purple, particularily in the spring and fall. A similar grass, meadow fescue, is a frequent weed in bluegrass lawns.
Foxtails are warm season annuals. Yellow foxtail has flattened stems that are often reddish colored on the lower portions. The stems of green foxtail are round. The seed of yellow foxtail is four times as large as green foxtail. Giant foxtail may be found in some lawns.
An escape from cultivation that can become a troublesome weed in lawns. The nodding, bell-shaped flowers are showy, ranging from a deep blue to purple. Creeping bellflower is a cool-season perennial with a root system that is both fleshy and fibrous. The basal leaves are heart-shaped with long stems. The leaves on the flower stalks are long and narrow without stems.
A coarse warm season annual grass with a flattened stem especially near the base. Lower portion of the platt tends to be reddish purple. The seed head branches into 6 or 8 short compact segments.
A low-growing, compact, tufted winter annual. Some flattened stems may lie close to the ground. It does not have rhizomes. Leaves are soft, light-green, and boat-shaped at the tip. Starts growth from seed in early fall and often grows throughout winter. Can produce seed heads when mowed at 1/4″. May die suddenly during summer months.
A cool season perennial. Many bluegrass lawns that contain smooth brome were started with pasture sod. The leaves are 3/8 to 1/2 inch wide and tend to be lax rather than upright. Close examination of an entire leaf will reveal an “M” or “W” across the leaf blade. The lower portion of the stem is almost white with prominent veins. Smooth brome spreads primarily by underground stems.
A decidedly warm season annual most often found growing where bluegrass stands are thin. Germinates later than crabgrass. The stems tend to be flattened and near the base are whitish in color. Flower heads are thicker and more robust than on common crabgrass. The extensive fibrous root system makes it difficult to pull.
A warm season perennial grass. The wiry fine stems root at the nodes; root system is shallow and fibrous; forms circular patches or may be distributed throughout lawn. Objectionable in bluegrass lawns because of delayed spring growth and early dormancy in the fall.
A warm season annual grass most often found in sandy turf areas that have been on low maintenance programs. Stems are flattened and branched; may be confused with yellow foxtail before formation of the spiny burs.
Warm-season perennial. Triangular stems of sedges produce 3-ranked leaves from near the ground. Leaves light yellow-green and rather harsh. Lower portion of plant is fibrous and brown. Roots often terminate with small nutlets, about the size of a kernel of popcorn. Seed heads appear burlike. Plants grow rapidly in July and August. Several species of sedge are common to our region, but this one is most prevalent in lawns.
Cool season plants, generally annuals, most often found in the dense shade of trees and shrubs. The leaves and leaflike parts form whorls at distinct internals along the weak stems. The square stems have tiny sawtoothed appendages which cause plants to stick together and to clothing. The flowers are small with four white petals.
A deep rooted perennial vine that is one of the most difficult weeds to control. The spade-shaped leaves have rounded tips and vary in size. The funnel shaped flowers vary from white to light pink and are about the size of a nickel. The plant readily climbs over shrubs and other ornamentals. It spreads by both seed and roots.
A late-starting, rapidly growing summer annual. The green, smooth stems branch along the ground in all directions from the root forming a flat circular mat on the soil surface. The light-green, smooth, tongue-like leaves are grouped five to six together forming whorls at each joint on the stem. Flowers are small, white, with several at each joint.
A perennial with creeping stems that root at the nodes. The leaves are opposite, 2-3 times longer than wide, clammy, and hairy. Flowers have five white petals. The root system is shallow and fibrous.
A cool season perennial legume that spreads by underground and above ground stems. May or may not be objectionable in lawns, depending on individual preference. Flowers white, sometimes with a tinge of pink. Seeds will live for 20 or more years in the soil.
A winter annual that starts growth in early fall. Slightly pubescent throughout. The squarish stems may be upright or spreading. Leaves are opposite with scalloped edges. Flowers are purple red.
Dock seldom flowers when growing in lawns. The plant froms a large rosette. Curly dock is most common and the leaves have crinkled edges. They are often tinted with red or purple color. Pale dock has leaves that tend to be more flat and broad. Both species have flowering stalks that may reach a height of two to three feet.
The slender, smooth, leaves are hollow and attached to the lower portion of the waxy stems. Both bulbs and bulblets are produced underground and the green to purple flowers are often replaced with bulblets. There is a characteristic onion-garlic odor. Wild onion is similar to wild garlic, but does not produce underground bulblets and the leaves are not hollow.
A winter annual that starts growth in September. Stems are squarish; plants usually upright. Flowers are lavender to blue. Leaves are opposite. A few plants may bloom in the fall, but the majority blossom in early spring.
A cool season perennial originally introduced as a ground cover, but is now a weed in many lawns. Thrives in shade, but will also grow in the sun. Ground ivy produces an abundance of lavender to blue funnel-form flowers in early spring. The square stems may root at each joint where they touch the ground.
An annual that thrives from early spring to late fall. Germination occurs in very early spring. Grows flat from a long white taproot. Individual plants may have a spread of 2 feet or more. Stems wiry, very leafy; at each leaf node there is a thin papery sheath. Leaves often have a bluish cast. Seeds are three-cornered, light-brown early and shiny black at maturity.
A versatile annual capable of adapting itself to a wide variety of environmental conditions. In lawns, it assumes a prostrate habit of growth; if not mowed it may attain a height of 7 or 8 feet. The first leaves after germination are covered with a silvery pubescence. Germination starts in early spring and continues throughout the summer. Leaves and stems vary in color from greenish yellow to greenish red.
Common mallow and dwarf mallow are the most prevalent species. The long fleshy taproot is almost white. Flowers are bluish white. The seed portion is a flattened disc which breaks into 10 to 20 pie-shaped segments.
An annual or short lived perennial legume with trailing stems that grow close to the ground. The taproot penetrates deeply into most soils. The three-leaflet leaves have prominent veins and are similar to most other clover leaves. The small clusters of flowers are bright yellow. Seed pods turn almost black at maturity. Black medic is most noticeable in lawns during June, July, and August.
A primitive form of plant life consisting of many genera and species. Moss prefers an environment that is cool and moist. It is most often found in shaded areas such as the north side of buildings and on poorly drained soil.
A warm season prostrate annual that grows from a pink taproot. The leaves are very shiny. Stems smooth, light-green to reddish green, may spread 1 1/2 to 2 feet. Seeds are lens shaped, small, and shiny black.
Cool season perennials that form rosettes with prominently veined leaves. The leaves of blackseed are oval shaped and 2 to 3 inches across with purplish stalks; broadleaf plantain has smaller leaves without purplish coloration. Both species have rat-tail like seed heads that are several inches long.
Has slender, narrow leaves that are about one inch across with 3-5 prominent veins. The seed head is a short cylindrical spike.
A prostrate freely branching warm season annual. Plants slightly hairy. Some stems may be four or five feet long. Taproot. Leaflets bright green. Flowers yellow. Seeds angled, each with 2 stout spines that give a Texas longhorn appearance.
A warm season annual. Leaves and stems fleshy or succulent, reddish in color. Grows prostrate. Root system tends to be fibrous; stems root wherever they touch the ground, particularly if the main root has been destroyed. Flowers small, yellow. Seeds very small, black.
A winter annual. The deeply lobed leaves form rosettes in the fall that may be confused with dandelions; however, the leaves lack the milky sap. Blooms in very early spring. White flowers develop into triangular seed pods filled with numerous tiny reddish brown seeds.
A low growing, cool season perennial that reproduces by creeping roots and seeds. Leaves are spear shaped. The lacy flowering stalks bloom in mid-spring with a definite reddish color. The seed is small, three-sided and reddish brown. Remains green from very early spring to early winter.
Several weedy species exist, most being winter or early spring annuals. Plants very low growing; leaf shapes vary with species but generally are small and numerous; flowers are light blue with white throats. Seed pods are divided and almost heart-shaped.
A prostrate growing warm season annual. Spotted spurge has hairy stems and leaves with a prominent purple spot on each leaf. Prostrate spurge has hairy stems and leaves but no spots. Most prominent in July, August, and September. Milky sap. Seeds are born in three’s in a capsule.
May spread by horizontal roots. Leaf form may vary. Most varieties have dark green spiny lobed leaves with crinkled edges. The lavender flowers are 3/4″ or less in diameter.
A biennial found in lawns as a rosette. Leaves are free of hair and have a light colored midrib. Leaf margins are usually edged in grey-green. Spiny. Flowers are large, powder puff in shape, and usually deep rose to violet in color.
A warm season annual that may on occasion act as a perennial. Low growing, hairy throughout. Stems branch freely in all directions, forming circular patterns of growth. Leaves vary in size and form, often are wedge-shaped and toothed. Taproot. Small funnel-form flowers are blue to purple.
Cool season perenials that are among the first plants to bloom in the spring. Prefer at least partial shade. Flower color varies from very light blue to deep purple. Occasionally become troublesom in lawns.
Classified as a perennial, but more often performs as a warm season annual. Stems branch from the base. The leaves are palmately divided into three leaflets giving a cloverlike appearance. Funnel-form flowers are yellow. The seed pod is cylindrical, 5-sided, and pointed. The plants contain soluble oxalates which give it a rather pleasing sour taste.
May grow one to two feet tall. Leaves are soft, finely divided, fern-like. Stems and leaves are covered with grayish-green fine hairs. Flowers are mostly white forming a flat flower-cluster. Entire plant is rather strongly scented.
*Illustrations and descriptions provided by Lawn Weeds and Their Control, North Central Regional, Extension Publication No. 26, 1992.
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.
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.
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
|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
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
|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.|
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.
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.
10 Weeds That Look Like Grass
Mother Nature can be a clever mistress, indeed. She can be so clever that she can disguise a variety of different common weeds that look like desirable grasses.
An invasion of such a grassy weed is insidious. It doesn’t appear to be a serious problem for your lawn until it’s already become a serious problem.
These weeds hide in plain sight and can be easily overlooked if you don’t know what you’re looking for.
That’s what this article is all about. We are going to provide you with a list of weeds that look like grass. You’ll discover how to identify each grassy weed and learn some different control methods for each one.
So, before these common weeds that look like common lawn grasses become an issue, let’s dive in and take a look.
1. Annual Bluegrass (Poa annua)
What it Looks Like
Annual bluegrass (Poa annua) is one of the most commonly misidentified weed grasses. It is a close relative of the desirable cold-season Kentucky bluegrass.
As with all members of the Poa genus, annual bluegrass has canoe-shaped tips on its grass blades. Because they mimic the shape of other Poa species, the best way to identify these grassy weeds is to look for their brighter and lighter green color.
Annual bluegrass also has a long ligule, or membrane, that connects that leaf blade to the base of the stem.
Annual bluegrass is also a cold-season weed grass. They tend to congregate in shady areas with excess moisture. The heat and light from the sun will dry these grassy weeds out and leave bare patches in your yard.
Annual bluegrass can be treated with both pre-emergent and post-emergent herbicides. However, the best way to ensure that you don’t have it hiding on your lawn is to create a habitat not suitable for its growth.
If you have areas of your yard that are shaded, open them up by trimming back the trees or shrubs that provide the shade. For moist areas, ensure that the soil isn’t compacted and is properly draining. These two prevention methods should do your grass justice and keep annual bluegrass at bay.
2. Crabgrass (Digitaria sanguinalis and Digitaria ischaemum)
What it Looks Like
If you’ve not heard of crabgrass, then you’re not spending enough time outside. Because these grassy weeds are everywhere. Digitaria sanguinalis (also called large crabgrass) is predominantly found in the northern part of the country, and Digitaria ischaemum (also called smooth crabgrass) is the crabgrass species that dominates the southern part.
But crabgrass is crabgrass. And none of it’s good. This grassy weed makes its home on unhealthy yards. So if your lawn is under-watered, under-fed, and poorly drained, then you’re probably going to have a problem with crabgrass.
Crabgrass plants are annual weeds that will die off each year. That may sound like good news until you hear that each crabgrass plant is capable of producing more than 150,000 seeds that can germinate every spring.
Crabgrass grows in clumps on your lawn. While it does look similar to normal grasses, it has a much thicker growth habit and is altogether an unattractive eyesore on your lawn. If the seeds do germinate and grow unchecked, the blades can grow as long as 2 feet. Crabgrass is generally a lighter green than most desirable lawn grasses. Once its root system is established, it spreads quickly and aggressively across your lawn.
Just like annual bluegrass, you can get rid of crabgrass with one of many selective pre-emergent herbicides to prevent the seemingly countless seeds from germinating. If you’re too late for that, a selective post-emergent herbicide will also clear up the problem. However, your best bet if the seeds have already germinated is to recognize and pull the crabgrass plants before they’re old enough to go to seed.
The best defense, however, is a good offense. And a good offense, in this case, is ensuring that your lawn is healthy and thick. Take care to ensure proper fertlization, watering, and drainage on your property. This will keep your desirable grass too thick and healthy for crabgrass to invade.
3. Yellow Nutsedge (Cyperus esculentus)
What it Looks Like
Yellow nutsedge is a perennial weed that can attack your lawn from above the soil and below. Seeds can be spread through the air from above the soil level and through its rhizomes, or tubers, below the soil’s surface.
The fact that it’s a perennial weed that will reappear each growing season only complicates matters further.
When yellow nutsedge is young, it will have light green colored grass blades. As it ages, the grass blades will become a deeper green. This change in color can make it hard to identify amongst your desirable lawn grass.
Yellow nutsedge is best identified by looking at its root system. On its roots, there will be nut-like tubers growing from them. These tubers give the grassy weed its name.
The best plan of action for controlling yellow nutsedge is to keep your lawn lush and healthy. A healthy lawn will do its own work and prevent nutsedge from having a place to invade. So be sure to do the upkeep using proper maintenance practices, and you should be fine.
Since yellow nutsedge is a perennial grassy weed, once it shows up on your lawn, the best way of getting rid of it is a heavy dose of post-emergent herbicide.
Pulling the weeds may cause you more problems because leaving the smallest piece of these plants in the soil guarantees that they will regenerate and make a repeat appearance on your lawn. If you decide to go this route, ensure that you remove every single fiber of the yellow nutsedge from the ground.
4. Green Foxtail (Setaria viridis)
What it Looks Like
Green foxtail earns its name because, once it is fully grown, a piece of the plant resembles the tail of a fox. This piece that resembles a fox tail is a seedhead that can produce hundreds of problematic seeds that can spread through your lawn and garden.
Green foxtail is an annual grassy weed that will require the germination and growth of brand new plants every year.
Identification can be tough before the plant grows its seedhead. Its blades are a normal green color and don’t have a remarkably different shape than most desirable lawn grasses. Its growth habit is normal as well. So this one can be tough to spot.
Since it’s an annual weed, you can control green foxtail by pulling it out. Preferably, you’ll have it removed before it goes to seed. But, as you already know, this can be a difficult task because it looks so similar to your grass before that point.
If you find that green foxtail has already gone to seed, you can pull the plant from the soil and use a pre-emergent herbicide to keep the green foxtail’s seeds from germinating in the spring.
If the invasion is too great to pull all of the grassy weed out, you can use a selective post-emergent herbicide to kill it off. You’ll still need to treat the ground with a pre-emergent herbicide at some point before the seeds begin to germinate when the weather warms up.
5. Creeping Bentgrass (Agrostis stolonifera)
What it Looks Like
Creeping bentgrass is often planted intentionally. But this intentional planting is usually relegated to the fairways and putting greens on manicured golf courses and not on your yard.
Creeping bentgrass can spread aggressively in your grass and garden through its stolons.
Creeping bentgrass will appear in light green patches in your grass. Its blades are generally finer and thinner than most desirable grasses. If you allow creeping bentgrass to grow taller than 1 inch, it will take on a puffed-up or swollen appearance.
Cool-season creeping bentgrass is averse to excessive heat and will turn brown quickly at even slight elevations in temperature.
Because creeping bentgrass propagates and spreads through its stolons beneath the soil’s surface, one plan of attack is to use selective herbicides on this hardy perennial plant. An herbicide containing glyphosate is your best bet. However, this may only work if you catch these lawn weeds very early in their life cycle.
Creeping bentgrass is often more widespread than it may seem. This is due to it spreading underground through its stolons. On average, if you have a patch of creeping bentgrass with a diameter of 1 foot, you actually have a mix of the grassy weed and your desirable grass that extends three times that diameter. This makes spot-treating creeping bentgrass very difficult.
Unfortunately, the nature of these weeds makes them very difficult to completely eradicate once they are established. So, you’re either going to have to start over by removing all the grass entirely and reseeding or start promoting the growth of creeping bentgrass on your property.
To promote creeping bentgrass, you’ll need to shift your focus from soil fertility and nutrition to pest control. Because pests are one of this weed’s primary afflictions.
6. Common Couch (Elymus repens)
What it Looks Like
Common couch is a hardy perennial grassy weed that also goes by couchgrass and quackgrass. These weeds are equally at home in shade and sun.
Common couch spreads through both its underground rhizomes and its airborne seeds. Once it is established, its root system becomes exceedingly difficult to remove completely. So, it’s best if you can catch it early.
Common couch has a coarse texture and will appear on your lawn in patches. It’s blue-green color can be hard to distinguish amongst some desirable grasses.
The blades of these grassy weeds look similar to fingers. Their growth habit wraps these finger-like blades around the stem at the base of the plant.
If it is allowed to grow unchecked, common couch will take over your lawn in no time. It makes its home on areas that are thinned or bare. So, an unhealthy lawn makes the perfect victim for these weeds.
Whenever you come across common couch in your lawn or garden, you can pull it up by hand. But, if you do, you need to ensure that every piece of the plant is removed from the soil. Otherwise, you’re destined for another visit as soon as it can regenerate.
Chemical control will require both pre-emergent and post-emergent herbicides because it spreads underground through its rhizomes. So you have to ensure that the hardy root system is dead to prevent its propagation.
The best defense against common couch (and this feels like it’s becoming a theme) is a healthy, vibrant, and thick lawn. It will outgrow the weeds, and they won’t have any space to invade.
7. Smooth Bromegrass (Bromus inermis)
What it Looks Like
Just like couchgrass, smooth bromegrass is a perennial weed that can spread through either rhizomes or seeds. It also has a robust root system that will be difficult to get rid of once it becomes established in your lawn.
Smooth bromegrass can grow to heights of over 7 feet. Its blades, or leaves, grow to between 8 inches and 2 feet long. The blades hang down in a drooping manner. The blades are covered on both the upper and lower surfaces by fine hairs.
This weed’s color ranges from a light to a normal shade of green. The upper portions of the blades can be lighter in color because of their length if growing conditions are poor.
Fortunately, you can control smooth bromegrass by keeping it cut short with your mower or weedeater. Keeping it short will allow your desirable grass to crowd it out eventually, and you won’t have to resort to any chemical herbicides.
However, if the weeds have spread out and established themselves, you’ll need to use some strong pre-emergent and post-emergent herbicides to quell the invasion. Use an herbicide with glyphosate for the best results.
8. Carpetgrass (Axonopus compresus and Axonopus affinis)
What it Looks Like
These weeds share the same genus and have similar physical traits, so they’re lumped together under one name. Carpetgrass is a perennial weed that can grow to heights of a foot or more. It will appear on your lawn in very thick mats that are shaded a normal green color.
In the summer, they will produce seed heads that look very similar to those of crabgrass. The seed heads will be taller than the rest of the plant.
Carpetgrass prefers acidic soil with high moisture content. You will probably find them congregating and growing in shady areas that do not receive adequate sunlight. This allows the moisture levels to build up in the soil.
One good thing about carpetgrass is that you can control it through natural methods. All you have to do is raise the pH level of the soil. You can do this by adding lime or salt mixed with a gallon of water. One of these two should do the trick.
Of course, if you catch it early enough, you can pull it from the earth. However, since it is a perennial weed, you’ll need to ensure that you remove every last piece of it from the ground.
9. Tall Fescue (Festuca arundinacea)
What it Looks Like
This may be confusing because tall fescue is used as a desirable grass on some lawns. However, much like creeping bentgrass, it can show up without an invitation and take over your lawn. Ironically, the very things that make this such a desirable grass are also the things that make it a worthy opponent in your yard.
Tall fescue has distinct blades or leaves. The leaves of tall fescue are thick and broad. They have pronounced veins running the length of the blades, and this gives them a coarse texture. The blades are colored bright green, and the lower surface is a lighter green than the upper surface.
When it comes to tall fescue, I have some good news and some bad news. The bad news is that it is an extremely hardy plant that is very drought resistant. Once it shows up in your grass, it can be challenging to remove it completely.
It spreads through underground rhizomes, so its initial damage assessment may be underestimated. It can be spread further than it appears at first.
The good news is that you can beat tall fescue with natural means. Solarization is the best technique to use. Cover the weeds up with black plastic, newspaper, a tarp, or cardboard and let the heat, combined with a lack of sunlight and oxygen, suffocate the invasion out of your yard.
10. Johnsongrass (Sorghum halepense)
What it Looks Like
Johnsongrass is a perennial weed that is relatively easy to identify and control, which is a different story than the rest of the perennial weeds in this article.
When johnsongrass is in its early stages of life, it resembles the seedlings of the corn plant we all know and love. Left to grow unchecked, it can reach heights of over 7 feet.
Its seed head will start out green and then transition to a purplish maroon color.
As johnsongrass matures on your lawn, you’ll be able to pick it out because its leaves will become up to an inch thick and have a distinct white vein running down the middle of each blade.
There’s an easy way to control it and a hard, labor-intensive way to control it. The easy way is to cover the entire plant with highly concentrated vinegar. Be careful not to spray anything you don’t want to kill because vinegar is non-selective.
The hard, labor-intensive control method is used for larger johnsongrass invasions. It spreads through its rhizomes under the soil along with its seeds. So, to kill the johnsongrass, you’ll need to expose those rhizomes to the elements by using a tiller to cultivate the earth containing them. Do this later in the fall and expose the rhizomes to the cold winter temperatures, and they won’t be making a second appearance in the spring.
Jeffrey Douglas own a landscaping company and has been in the business for over 20 years. He loves all things related to lawns or gardens and believes that proper maintenance is the key to preventing problems in the first place.