Tall weeds that forms a y with black seeds

The Only Weed Identification Guide You’ll Ever Need: 33 Common Weedy Plants to Watch For

Don’t let these pesky plants crash your garden party! The first step is to know your enemy. Then you’ll know the best way to deal with your weed problem.

1 of 34

What is a Weed, Anyway?

A weed can be any plant growing where you don’t want it to. However, there are some particularly weedy species to keep an eye out for. These aggressive plants not only make your yard look messy, they can also choke out the garden plants you’ve worked so hard to grow. Whether you’re trying to identify lawn weeds or garden weeds, this handy guide will help you identify more than 30 common weeds by photo, plus give you tips for how to best remove them.

1 of 34

2 of 34

Dandelion

Type: Broadleaf perennial

Size: 12 inches tall, 6 – 16 inches wide

Where It Grows: Lawns and gardens in sun or shade

Appearance: This common lawn weed has a long taproot; leaves are deeply notched. Yellow flowers mature into puffballs. Dandelion seeds are like parachutes that fly away in the wind, helping them invade new spaces in lawns and garden beds.

Weed Control Tips: Mulch to prevent dandelions in gardens. Pull dandelion weeds by hand or treat lawns with a broadleaf herbicide, which won’t kill grass.

2 of 34

3 of 34

Oxalis

Type: Broadleaf perennial

Size: To 20 inches tall

Where It Grows: Sunny or shady landscape, lawn, or garden areas

Appearance: This garden weed has light green leaves that look a little like clover and cup-shape yellow flowers in summer and fall.

Weed Control Tips: Mulch garden areas in spring to prevent weeds. Pull oxalis weeds by hand or spray weeds with a broadleaf herbicide in spring or fall.

3 of 34

4 of 34

Crabgrass

Type: Grassy annual

Size: To 18 inches tall and 20 inches wide

Where It Grows: Lawn, landscape, and garden areas in sun or shade

Appearance: Crabgrass is exactly what it sounds like: A grassy weed. This lawn weed grows roots anywhere the stem makes soil contact. Seed heads spread out like four fingers.

Control: Use a preemergence weed preventer to prevent seeds from sprouting, pull crabgrass by hand, or spot-treat with a nonselective herbicide if growing in sidewalk cracks or other places where nothing else is growing.

4 of 34

5 of 34

Bindweed

Type: Broadleaf perennial

Size: Climbs 6 feet or more

Where It Grows: Landscape and garden areas in sun

Appearance: Identify this garden weed by its arrowhead-shape leaves on twining vines. Bindweed also produces white to pale pink morning glory-type flowers.

Control: Mulch your garden to prevent bindweed. Repeatedly pull or cut down growing bindweed plants and/or spot treat with a nonselective herbicide designed to kill roots, not just above-ground growth.

5 of 34

6 of 34

White Clover

Type: Broadleaf perennial

Size: 8-10 inches tall, 12 inches wide

Where It Grows: Lawn, landscape, and garden areas in sun to partial shade

Appearance: White clover has three-lobe leaves and round white flower clusters. The plants quickly spread outward to form dense mats of foliage.

Control: Mulch your garden beds to prevent white clover in landscape areas. Use an iron-based herbicide to get rid of clover growing in lawns or dig out the weeds in garden beds.

Test Garden Tip: Clover adds nitrogen to the soil plus the flowers feed many pollinators so some gardeners use this plant to create a more environmentally friendly lawn.

6 of 34

7 of 34

Nutsedge

Type: Grass-like perennial

Size: 2 feet tall, 1 foot wide

Where It Grows: Lawn, landscape, or garden areas in sun or shade

Appearance: Nutsedge has slender, grassy leaves, triangular stems, and small, nutlike tubers on the root system. When these weeds pop up in lawns, they often grow faster than turf grass, so they are easy to spot.

Control: Mulch garden areas in spring to help prevent nutsedge. Plants are easy to pull up by hand, but it will take repeated weeding to get rid of an infestation. Various herbicides are labeled for use on nutsedge in lawns but it is important to use the right one for the type of turf grass you have to avoid damaging it.

7 of 34

8 of 34

Creeping Charlie

Type: Broadleaf perennial

Size: 4 inches tall, several feet wide

Where It Grows: Shady lawn, landscape, or garden areas

Appearance: Identify this lawn weed and groundcover by its scalloped leaves, creeping stems, and clusters of purple flowers in late spring.

Control: Mulch garden areas in spring to prevent creeping charlie. Pull plants by hand or spray with a postemergence herbicide in spring or fall.

8 of 34

9 of 34

Lamb’s-Quarter

Type: Broadleaf annual

Size: To 4 feet tall and 18 inches wide

Where It Grows: Landscape and garden areas in sun or shade

Appearance: Lamb’s-quarter’s scalloped, triangular leaves have gray undersides.

Control: Mulch your garden to prevent lamb’s-quarter. Pull weed plants by hand or use a postemergence herbicide.

9 of 34

10 of 34

Plantain

Type: Broadleaf perennial

Size: To 8 inches tall and 12 inches wide

Where It Grows: Moist lawn and garden areas in sun or shade

Appearance: When you’re identifying weeds in your garden, if you spot broad, flat, oval-shape leaves arranged in a low rosette, you’ve likely found a plantain.

Control: Mulch to prevent plantains growing in the garden. Pull these weeds by hand or use a postemergence herbicide in lawns.

10 of 34

11 of 34

Dayflower

Type: Annual grass relative

Size: To 30 inches tall and wide

Where It Grows: Sunny or shady landscape areas

Appearance: Dayflowers have dark green leaves sprouting from a stem and brilliant blue flowers through the summer.

See also  Farabi weeds bad seeds

Control: Mulch the garden to prevent weeds or use a preemergence herbicide in spring. Pull weeds by hand or spot-treat with a nonselective postemergence herbicide.

11 of 34

12 of 34

Purslane

Type: Broadleaf annual

Size: To 6 inches tall and 2 feet wide

Where it grows: Dry, sunny landscape and garden areas

Appearance: Identify this weed groundcover by its fleshy, dark green leaves and small yellow flowers at the ends of the stems.

Control: Mulch your garden to prevent purslane or use a preemergence herbicide in the spring. Pull plants by hand or spot-treat with a nonselective postemergence herbicide.

12 of 34

13 of 34

Velvetleaf

Type: Broadleaf annual

Size: To 6 feet tall and 3 feet wide

Where It Grows: Fertile, sunny landscape and garden areas

Appearance: Velvetleaf gets its name because of its large, velvety heart-shape leaves up to 10 inches across. The weed blooms with yellow flowers in summer.

Weed Control: Mulch your garden to prevent velvetleaf or use a preemergence herbicide in spring. Pull existing plants by hand or use a postemergence herbicide.

13 of 34

14 of 34

Wild Violet

Type: Broadleaf perennial

Size: 6 inches tall, 6 inches wide

Where It Grows: Shady lawn, landscape, or garden areas

Appearance: Wild violet is a groundcover with heart-shape leaves and purple flowers in late spring.

Control: Mulch garden beds in spring to prevent wild violet. Pull weeds by hand or spray with a postemergence herbicide in spring or fall.

Test Garden Tip: This plant is sometimes grown as an ornamental in shade gardens.

14 of 34

15 of 34

Smartweed

Type: Broadleaf annual

Size: To 42 inches tall and 30 inches wide

Where It Grows: Sunny landscape and garden areas

Appearance: Identify garden weeds like smartweed by its lance-shape leaves often marked with purple chevrons. It’s an upright plant with pink or white flowers in summer and fall.

Control: To prevent this weed, mulch garden beds in spring. Pull plants by hand or apply a postemergence herbicide once it grows.

Test Garden Tip: This weed is native to areas of North America. Unlike many exotic weeds, it does support local wildlife.

15 of 34

16 of 34

Quickweed

Type: Broadleaf annual

Size: To 2 feet tall and wide

Where It Grows: Sunny landscape and garden areas

Appearance: Quickweed has jagged, hairy leaves and small white daisy-shape flowers in summer.

Control: Use a mulch or a preemergence herbicide in spring to prevent quickweed. If plants do grow, pull them by hand or spot-treat them with a postemergence herbicide.

16 of 34

17 of 34

Pigweed

Type: Broadleaf annual

Size: 6 feet tall, 2 feet wide

Where it grows: Sunny landscape or garden areas

Appearance: Pigweeds are tall plants with a taproot. Identify weeds by their hairy-looking clusters of green flowers (though some varieties are grown as annuals).

Control: Mulch garden areas in spring to prevent pigweed or use a preemergence herbicide in spring. Pull weeds by hand or spray with a postemergence weed killer.

17 of 34

18 of 34

Canada Thistle

Type: Broadleaf perennial

Size: To 6 feet tall and 3 feet wide

Where It Grows: Sunny lawn, landscape, or garden areas

Appearance: Canada thistle has spiny, gray-green leaves and purple flowers.

Control: Mulch your garden to prevent it in landscape areas. Use a postemergence herbicide in lawns in spring or fall, or dig the weed out by hand.

Test Garden Tip: Thistle has an extensive root system that can grow several feet out from the main plant.

18 of 34

19 of 34

Knotweed

Type: Broadleaf annual

Size: To 8 inches tall and 2 feet wide

Where It Grows: Sunny or partly shaded lawn, landscape, or garden areas

Appearance: Knotweed is an invasive groundcover with blue-green leaves sparsely appearing on long stems.

Control: Prevent knotweed with a deep layer of mulch or apply a preemergence herbicide in spring. Once the plant grows, hand-pull or spot-treat it with a nonselective weed killer.

19 of 34

20 of 34

Pokeweed

Type: Broadleaf perennial

Size: To 10 feet tall and 2 feet wide

Where It Grows: Sunny landscape or garden areas

Appearance: Identify this garden weed by its light green leaves, clusters of white flowers, and dark purple berries.

Control: Prevent pokeweed with a deep layer of mulch. Once the plant grows, hand-pull or spot-treat it with an herbicide.

20 of 34

21 of 34

Poison Ivy

Type: Broadleaf perennial

Size: To 15 feet tall and wide

Where It Grows: Sunny or shady landscape or garden areas

Appearance: Poison ivy can be a vine, shrub, or groundcover. The weed has leaves divided into three leaflets and can sprout clusters of green berries.

Control: Prevent poison ivy with a deep layer of mulch. If the weed starts to grow in your yard, spot-treat it with an herbicide or wrap your hand in a plastic bag, pull the plant up, roots and all, and carefully invert the plastic bag around the plant, seal, and throw away.

Test Garden Tip: The plant contains oils that cause a severe allergic skin reaction in many people when touched. These oils are present even on dead leaves and can become airborne and inhaled if the plant is burned.

Bahiagrass

Bahiagrass (Paspalum notatum), also known as highwaygrass, is an aggressive, warm-season perennial grass. Bahiagrass has a mat-forming habit with a light green color, coarse texture, and open canopy. It is native to South America and was introduced into the U.S. in Florida as a forage grass around 1913.

Bahiagrass is easily identified by its distinctive “Y-shaped” seed head. It tolerates a wide range of soil conditions and spreads by seeds and rhizomes (a horizontal, modified stem found at or just below ground level). Bahiagrass growth is favored by drought, so it is an indicator plant for droughty soil conditions. The aggressive nature and drought tolerance of bahiagrass make it ideal for erosion control along roadsides and highway rights of way. However, its aggressive nature also makes it difficult to control as a weed in the landscape.

See also  How to know what type of weed seeds you have

Bahiagrass habit with seed heads.
Ted Bodner, Southern Weed Science Society, Bugwood.org

Bahiagrass has distinctive “Y-shaped” seed heads.
Bert McCarty,©Clemson University

Before starting a weed control program, homeowners should realize that the complete eradication of bahiagrass (or any weed) from the landscape is not practical. A more practical approach is to control (not eradicate) the weed by limiting the infestation to a tolerable level.

Control in Lawns

Maintaining the health and density of your lawn is the best method for preventing a weed problem. Proper mowing height, irrigation, and fertilization of turfgrass will be the best defense against weeds. For more information on these topics, see the following fact sheets: HGIC 1201, Fertilizing Lawns; HGIC 1205, Mowing Lawns; and HGIC 1207, Watering Lawns.

If bahiagrass becomes a problem in a turf area, it can be dug up, or an herbicide may be used. If an herbicide treatment is chosen, treatments should be timed appropriately for optimum effectiveness.

Since bahiagrass is a perennial weed that also reproduces by rhizomes, post-emergent herbicides will also be necessary for improved control. Post-emergent herbicide applications should start in May when bahiagrass is small and starting to actively grow. See table for safe herbicides according to turf species.

Turf Tolerance to Post-emergence Herbicides for Bahiagrass Control.

Herbicide Bermudagrass Centipedegrass St. Augustinegrass Tall Fescue Zoysiagrass
sethoxydim NR S NR NR NR
imazaquin S-I I I NR S
metsulfuron S S S-I NR S
atrazine D S S NR NR
S= Safe at labeled rates.
I= Intermediate safety, use at reduced rates. Temporary yellowing of the turfgrass may occur.
NR= Not Registered for use on and/or damages this turfgrass.
D= Dormant. However, with the mild winters of recent years, bermudagrass lawns may not become completely dormant.

Once bahiagrass weeds have been eliminated in areas of the turf, bare spots will be left behind. To prevent the invasion of new weeds in these bare spots, it is best to fill them with plugs or sprigs of the desired turfgrass.

Glyphosate: Non-selective herbicides, such as glyphosate, can be used for spot treatments; however, desirable grasses can be severely injured or killed with contact. Multiple applications of glyphosate will be required to control bahiagrass. Examples of glyphosate products in homeowner sizes are:

  • Roundup Original
  • Martin’s Eraser Systemic Weed & Grass Killer
  • Tiger Brand Quick Kill Grass & Weed Killer
  • Ultra Kill Weed & Grass Killer Concentrate
  • Ace Concentrate Weed & Grass Killer
  • Bonide Kleen-up Grass & Weed Killer
  • Gordon’s Groundwork Concentrate 50% Super Weed & Grass Killer
  • Monterey Remuda Full Strength 41% Glyphosate
  • Hi-Yield Super Concentrate Killzall Weed & Grass Killer
  • Southern States Grass & Weed Killer Concentrate
  • Zep Enforcer Weed Defeat III
  • Eliminator Weed & Grass Killer Super Concentrate

If it is not practical to prevent glyphosate from getting on desired grasses, then a selective herbicide should be used. The following information is a guideline for choosing a selective herbicide according to turfgrass type.

Atrazine: Atrazine is a post-emergence herbicide for bahiagrass control that also has pre-emergence activity to give fair control of bahiagrass seed. It will also give post-emergence control of many broadleaf weeds. However, it is only safe to use on centipedegrass and St. Augustinegrass lawns. For maximum effectiveness, apply atrazine when air temperatures reach 65-70 °F for four consecutive days. Examples of atrazine products in homeowner sizes are:

  • Hi-Yield Atrazine Weed Killer Concentrate
  • Southern Ag Atrazine St Augustine Weed Killer Concentrate

Sethoxydim: For centipedegrass lawns, the use of sethoxydim (BASF Segment II Herbicide or Bonide Grass Beater Over-The-Top Grass Killer) will suppress bahiagrass. Sethoxydim should be applied no sooner than 3 weeks after centipedegrass spring green-up. Wait until lawns are fully greened. For a more effective bahiagrass treatment, do not mow 7 days before or after treating with sethoxydim. Reapply sethoxydim 3 weeks after initial application to suppress bahiagrass growth and seed head development. Do not make more than two applications per growing season.

Imazaquin: Image Kills Nutsedge is a homeowner-packaged, post-emergence herbicide product that will aid in the control of and reduce competition from bahiagrass. It may be applied to established bermudagrass, Zoysiagrass, centipedegrass, and St. Augustinegrass but do not apply to tall fescue. Do not apply imazaquin to St. Augustinegrass for other weed control during the winter. Do not apply imazaquin just prior to or during spring transition (green-up of the lawn). Do not use imazaquin in vegetable gardens, and do not use the grass clippings from treated lawns as mulch in landscape beds or around vegetables, fruit trees, or small fruit plants. A repeat application may be made for difficult to control weeds after 6 weeks.

Metsulfuron: Quali-Pro MSM Turf Herbicide, Quali-Pro Fahrenheit, and Blindside Herbicide are professional use herbicide products that will control bahiagrass, as well as many broadleaf weeds.

Metsulfuron can be used on bermudagrass, St. Augustinegrass, centipedegrass, and zoysiagrass. The Quali-Pro Fahrenheit also contains dicamba for broadleaf weed control. Blindside Herbicide also contains sulfentrazone for nutsedge control.

A non-ionic surfactant (such as Southern Ag Surfactant for Herbicides, Hi-Yield Spreader Sticker, or Bonide Turbo Spreader Sticker) is required at 2 teaspoons per gallon of spray mix for best control with the metsulfuron products above. Read the metsulfuron product label for more information. Some discoloration of turfgrass may occur after the application of metsulfuron, and increased yellowing and stunting of turfgrass may occur with the addition of the surfactant. A repeat application may be required in 4 to 6 weeks for best control of bahiagrass. Follow label directions for a reduced rate on centipedegrass.

See also  Weed seed bank management

Do not over-seed or re-sod for 8 weeks, or plant woody ornamentals in treated areas for one year after applying metsulfuron. Do not apply metsulfuron herbicides within two times the width of the drip line of desirable hardwood trees. Do not allow spray drift to contact desirable shrubs, and high temperatures at application may increase herbicide drift. Make metsulfuron applications when temperatures are below 85 °F. Allow one week between application of metsulfuron and other lawn pesticide products. Read the product label for other precautions for each turfgrass species.

Control in Vegetable Gardens

It is best to attempt to treat weeds before tilling the soil for a vegetable garden. Tilling can break up and spread weed seed and perennial grass rhizomes throughout the garden plot. Some methods used to remove weeds in the vegetable garden include hand pulling, mulch, and post-emergent herbicides.

Cultural Control: Hand pulling bahiagrass may be a practical choice for small garden plots. If hand pulling, be sure to work when the soil is moist so that the bahiagrass roots can easily be removed from the soil.

Organic mulch (such as pine needles, ground leaves, compost, old hay, or grass clippings) can be used in the garden to help suppress bahiagrass development. Before laying the mulch, apply a layer of 6 to 8 wet newspaper sheets to act as a weed barrier. The newspaper layer will prevent weed development by blocking light to the weeds underneath and prevent their growth. Best of all, the newspaper should decompose before next spring. To prevent low oxygen levels in the root zone, keep organic mulch levels at a maximum of 3-inches deep. For more information on mulching the vegetable garden, see HGIC 1253, Controlling Weeds by Cultivating & Mulching.

Glyphosate: A post-emergent herbicide can be used to treat the garden plot before planting. Glyphosate can be applied to the garden plot 3 or more days prior to planting. Glyphosate is most effective when weeds are actively growing, so do not apply during extreme heat, cold, or drought conditions. Multiple applications of a 1.5 to 2.0% glyphosate solution may be necessary to control perennial weeds like bahiagrass. See product label for mixing directions. For examples of glyphosate products in homeowner sizes, please see the “Control in Lawns” section.

Sethoxydim: Some products containing sethoxydim may be applied within the vegetable garden after planting. These will control most grass weeds, in addition to bahiagrass. However, do not apply near sweet corn. Examples of products labeled for use within vegetable gardens are:

  • Hi-Yield High Yield Postemergence Grass Herbicide
  • Bonide Grass Beater Over-the-Top Grass Killer Concentrate
  • Ferti-lome Over-the-Top II Grass Killer Concentrate
  • Monterey Grass Getter
  • Poast Herbicide

Control in Landscape Beds

In landscape beds, bahiagrass can be hand dug or controlled with an herbicide. As mentioned previously, it is best to prevent the invasion of bahiagrass by maintaining ideal growing conditions and using a 3-inch mulch layer to block weed development. Bahiagrass is a perennial weed that can emerge from both seeds and rhizomes. Once bahiagrass has made its way into the landscape bed, an herbicide may be necessary if hand pulling is not practical.

Glyphosate: A non-selective herbicide, such as glyphosate, can be used for spot treatments around ornamental plants but should be used with caution. Do not allow glyphosate spray mist to contact ornamental foliage or stems, as severe injury will occur. A cardboard shield may be used to prevent glyphosate spray from drifting to nearby ornamentals. For examples of glyphosate products in homeowner sizes, please see the list above in the “Control in Lawns” section.

Sethoxydim: Sethoxydim is a selective herbicide that can be applied safely in landscape beds containing most landscape plants but check the product label for a listing of tolerant plant materials. Sethoxydim will only control grass weeds; however, do not allow sethoxydim to contact ornamental grasses. A 2.5% solution should be applied before bahiagrass reaches 4 inches tall. Read label directions for mixing. Examples of products containing sethoxydim in homeowner sizes are:

  • Hi-Yield Grass Killer Postemergence Grass Herbicide
  • Bonide Grass Beater Over-the-Top Grass Killer Concentrate
  • Ferti-lome Over-the-Top II Grass Killer Concentrate
  • BASF Segment II Herbicide
  • Monterey Grass Getter

Glyphosate and sethoxydim are both more effective when weeds are actively growing and will not work well for weed control under drought conditions. As with all pesticides, read and follow all label instructions and precautions.

CAUTION: Atrazine and imazaquin can travel through soil and enter groundwater; please read the label for all environmental precautions. Users are advised not to apply atrazine or imazaquin to sand or loamy sand soils where the water table (groundwater) is close to the surface and where these soils are very permeable, i.e., well-drained.

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

Original Author(s)

Millie Davenport, Director of Home and Garden Information Center, Horticulture Program Team, Clemson University

Revisions by:

Joey Williamson, PhD, HGIC Horticulture Extension Agent, 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.