Louisiana is home to a diverse range of plant species, including many types of weeds. These pesky plants can be found in gardens, lawns, and agricultural fields across the state, often causing problems for farmers and homeowners alike. While some weeds are harmless, others can be invasive and difficult to control. In this article, we’ll take a closer look at some of the most common weeds found in Louisiana:
Table of Contents
Louisiana weeds
| Name of Weed | Family |
|---|---|
| Asiatic Hawksbeard | Asteraceae |
| Annual Bluegrass | Poaceae |
| Bahiagrass | Poaceae |
| Barnyardgrass | Paniceae |
| Carolina Geranium | Geraniaceae |
| Crabgrass | Poaceae |
| Chickweed | Caryophyllaceae |
| Common Bermudagrass | Poaceae |
| Common Lespedeza | Fabaceae |
| Dallisgrass | Poaceae |
| Dandelions | Asteraceae |
| Dichondra | Convolvulaceae |
| Dollarweed | Araliaceae |
| Doveweed | Spurges |
| False Garlic | Amaryllidaceae |
| Goosegrass | Poaceae |
| Green Kyllinga | Cyperaceae |
| Henbit | Lamiaceae |
| Indian Mock Strawberry | Rosaceae |
| Lawn Burweed | Asteraceae |
| Nutsedge | Cyperaceae |
| Sedges | Cyperaceae |
| Spurge | Euphorbiaceae |
| Torpedograss | Poaceae |
| Virginia Buttonweed | Asteraceae |
| White Clover | Apiaceae |
| Oxalis | Oxalidaceae |
Asiatic Hawksbeard
Asiatic hawksbeard is a common weed in Louisiana and throughout the south. It has yellow-green leaves, and small yellow flowers, and grows in dry conditions.
Type
Annual broadleaf
Family
Asteraceae
Control
Although cultural weed control methods such as proper lawn-mowing and watering practices can help reduce the spread of Asiatic Hawksbread in your yard, they may not be sufficient to eliminate this stubborn weed. For complete removal, it’s recommended to seek professional help and opt for the application of broadleaf weed killers.
Annual Bluegrass
Annual bluegrass is a common winter weed grass with bright green leaves. It spreads quickly through lawns and gardens. The weed is characterised by thin leaves with pointed tips and yellowish-green or light-green flowers. The weed species prefers moist soil and survives in sunlight as well as shade.
Type
Annual Grass
Family
Poaceae
Control
As annual bluegrass thrives in moist soil, the best way to control its growth and spread is to avoid overwatering the garden or lawn. Pre-emergent herbicide treatment is a great way to prevent the seeds from germinating. Applying herbicides in the autumn season also proves to be an effective control measure against bluegrass invasion.
Bahiagrass
Bahiagrass is a perennial grass with fine, green leaves. It has a tufted growth pattern and the stems are often reddish in colour. The species is found in sunny locations, such as agricultural fields, backyards and gardens.
Type
Perennial Grass
Family
Poaceae
Control
To control bahiagrass in garden beds, spot spraying with Glyphosate is recommended. For lawns, Atrazine can be used as a pre-emergent treatment. Imazaquin is effective for killing bahiagrass in most settings excluding areas where food items are grown. Follow-up spraying may be necessary regardless of the chemical used.
Barnyardgrass
Barnyardgrass, a widespread weed in the United States, is an annual grass that can be found in both cultivated and non-cultivated areas. It prefers moist soils but can also tolerate dry conditions. Young plants have brown and red stripes near the bottom of their leaves.
They form tufts, spikes, or dense clusters that can grow up to 120 cm in height. The panicles are relatively long, maxing out at 20 cm in length. These structures are often bristly and contain awns that can be either short or long. Barnyardgrass seeds are very durable and can remain viable for up to 15 years, making them difficult to get rid of once it becomes established.
Type
Grass
Family
Paniceae
Control
The best way to remove barnyardgrass is to pull it up by hand, making sure to remove the entire root system. It can also be controlled with herbicides, however, frequent and careful application of these chemicals is necessary in order to ensure that the weed does not return.
Carolina geranium
Carolina geranium is a summer annual weed found in lawns and gardens across the United States. It has bright green leaves with five lobes, resembling those of a maple tree. The flowers are pinkish or white and often have five petals. These weeds grow quickly, reproduce rapidly, and can choke out other plants in the garden if left unchecked.
Type
Annual broadleaf
Family
Geraniaceae
Control
Cultural control methods such as mowing regularly to remove young seedlings and using mulch to block sunlight are effective for controlling Carolina geranium. Herbicides can also be used; however, they must be applied when the weed is young or else they will not work.
Crabgrass
Crabgrass grows low on the ground and typically spreads out horizontally like a crab’s legs. It has flat, green leaves pointing outward and finger-like florets. The stems are spreading and branched. Its roots develop at the nodes on prostrate stems.
The weed prefers dry and hot conditions. It can be found in the disturbed areas of weedy meadows, prairies, lawns and gardens, fields, vacant lots, grassy paths, and along roads and railroads.
Type
Annual grass
Family
Poaceae
Control
It is possible to keep crabgrass growth and spread in check by regularly mowing the lawn. A pre-emergent herbicide application is the best way to prevent the weed from taking hold in a lawn or garden. The herbicide should be sprayed in the spring when crabgrass grows actively.
Chickweed
Chickweed is a low-growing weed, reaching a height of 30 cm. It sprawls on the soil surface to form mats of foliage. It can be identified by its simple, frosty leaves and white flowers with five petals.
The weed species grow well in the winter. It prefers cool, moist conditions, and does not tolerate hot temperatures. Chickweed can quickly spread over the bare land in a garden or lawn.
Type
Annual broadleaf
Family
Caryophyllaceae
Control
Chickweed can be removed by hand-weeding. However, it is time-consuming. When it comes to chickweed, prevention is the better option. When you notice a weed showing up in your garden or lawn, pull it out immediately. Appropriate herbicides and selective weedkillers can be used to control chickweed invasions.
Common bermudagrass
This weed species is a hardy, coarse-textured grass that spreads through underground stems and rhizomes. It has a deep green color and can be difficult to control due to its spreading habit. You’ll find Bermuda growing on thousands of golf courses because of its ability to withstand mowing.
A lot of people don’t actually consider Bermuda a weed because of its attractive appearance and its ability to be controlled with proper maintenance. However, it can become invasive if not managed properly. The drawback of Bermuda grass is that there are still people who prefer the look, feel, and color of Fescue because it remains green.
Type
Perrenial
Family
Poaceae
Control
- Mechanical: Hand pulling or mowing
- Chemical: Pre and post-emergent herbicides such as Roundup, Weed Beater Ultra, or Ortho Ground Clear can be used for controlling Bermuda grass.
Common lespedeza
Common lespedeza is a summer annual weed found growing in pastures, lawns, and hay fields. It is an upright plant with trifoliate leaves, small pink/ purple flowers, and slender pods that contain several seeds. The weed can be identified by its wiry stems and yellowish-green leaves.
It grows rapidly and can quickly take over a field or pasture if left unchecked. Lespedeza spreads through seed dispersal and forms dense patches of foliage that choke out other plants.
Type
Annual broadleaf
Family
Fabaceae
Control
For warm-season grasses, triazine herbicides are a reliable solution for controlling common lespedeza and its related species through postemergence applications. In the case of actively growing centipedegrass, Atrazine (such as Bonus S) can also be applied for effective control.
Dallisgrass
This weed species is a perennial grass with a coarse, upright growth habit. It often invades lawns and gardens where it can be difficult to control due to its aggressive growth and ability to spread rapidly.
Dallisgrass is a weed that commonly appears in clumps, has grayish-green leaves with a smooth texture, and features a striking vein down the center of each leaf.
Type
Perennial Grass
Family
Poaceae
Control
Dallisgrass is a really tricky weed to eradicate. Multiple post-emergent weed control applications are required, and it is important to make sure that the weedkiller is labelled for use on dallisgrass.
Dandelions
Dandelions are a common lawn weed with much-familiar, bright yellow flowers. The leaves are toothy, deeply notched, and hairless, forming a rosette just above the central taproot. The bright yellow flower heads turn into white puffballs containing seeds when they mature.
This weed species is not easy to control due to its deep and aggressive root system along with its quick germination capabilities.
Type
Perennial Broadleaf
Family
Asteraceae
Control
Small dandelion infestations can be controlled by hand-pulling the plant completely from the soil. In the case of established plants, a weedkiller applied in autumn helps eliminate them permanently. Post-emergent applications, if applied correctly, will help check their spread.
Dichondra
Dichondra is an invasive weed species that grow in lawns, gardens, and along the edges of paths. It has a low-growing habit with round leaves that emerge from a single stem. The weed can quickly take over entire sections of turf if left unchecked, smothering out other turfgrass species and becoming difficult to control due to its spreading rhizomes.
Type
Annual or perennial
Family
Convolvulaceae
Control
Using a quality herbicide like Celsius WG during late spring is the ideal method for eliminating dichondra on your lawn, especially while the weeds are younger and smaller. Herbicides become less effective as the weed matures and ages.
Dollarweed
Dollarweed is an invasive, perennial weed with a low-growing growth habit. It prefers wet, shady areas where it can spread quickly and form dense mats. The leaves are round and greenish-gray in color and give off a pungent odor when crushed.
Type
Perennial Broadleaf
Family
Araliaceae
Control
Spot Treatment is the best way to control dollarweed. Using a post-emergent herbicide is the most effective method for controlling dollarweed in your lawn. Applying a pre-emergent herbicide in the fall or winter can also help prevent its growth.
Doveweed
This weed species is an annual with a low-growing growth habit and almost hairless leaves. It usually appears in thin turf areas where it can spread quickly and be difficult to control. Doveweed prefers warm weather conditions, so it’s most active during the summer months. The leaves are smooth and a deep green, while the flowers grow in clusters and are vibrant purple.
Type
Annual Grass
Family
Spurges
Control
Doveweed is best controlled by regularly mowing your lawn as well as removing dead foliage from the area. Watering and fertilization requirements should also be kept up to date as doveweed is opportunistic and will colonize any thin or bare areas
False garlic
False garlic is a weed species that can be found in many lawns and gardens across the United States. It has thin, grass-like leaves with a unique smell when crushed. The flowers are small and white, while the bulbs are yellowish-white and clustered at the base of the plant.
Type
Perennial Broadleaf
Family
Amaryllidaceae
Control
If you cover bare soil with weed-control membranes, such as landscape fabric, or even thick black polythene, it can effectively block out light and potentially starve the bulbs. This process of exhaustion can take a couple of years before the bulbs are completely eradicated.
Goosegrass
Goosegrass is a summer annual grass that sprawls on the ground to form a mat-like rosette. Its leaf blades are thick and dark green with well-pointed seed heads. The finger-like spikes contain the seeds, and a single plant bears nearly 50,000 seeds!
The annual weed species has a well-developed root system, which makes it difficult to dig the plant out from the ground. Goosegrass thrives in compacted soil with no vegetation.
Type
Annual Grass
Family
Poaceae
Control
Keeping your lawn healthy is key to preventing goosegrass invasion. Core aeration is recommended every year because these weeds grow well in compacted soil. The use of post-emergent herbicides proves to be effective to get rid of established goosegrass.
Green kyllinga
Green kyllinga is an invasive, perennial weed species with a mat-forming growth habit. It has narrow, pointed leaves that grow in the shape of a fan and are bright green in color. The flowers are white or light yellow and appear on long spikes that extend above the foliage.
Type
Perennial Grass
Family
Cyperaceae
Control
Green kyllinga can be controlled chemically by using preemergent herbicides before the seeds germinate or selective post-emergent herbicides for established plants. Alternatively, a combination of preemergent and postemergent herbicide treatments can also be used to control green kyllinga effectively.
Henbit
Henbit is an annual broadleaf weed that has a low-growing growth habit. It can spread quickly and takes over areas in lawns with weak turf throughout the growing season. Its leaves are oval and serrated at the edges, while its flowers are purple and tubular.
Henbit’s fibrous root system allows it to grow to a maximum height of 16 inches. In addition, its reddish-purple flowers have dark spots on the lower petals and germinate in either fall or winter.
Type
Annual Broadleaf
Family
Lamiaceae
Control
Roundup is great for controlling Henbit, but the chemical should only be applied when the weed is actively growing. The best way to control Henbit is to keep lawns healthy with regular watering and fertilization. Additionally, pre-emergent herbicides can help prevent new weeds from germinating.
Indian mock strawberry
Indian mock strawberry is an invasive perennial weed species with a low-growing growth habit. It has bright green, arrowhead-shaped leaves that grow in clusters and white five-petaled flowers. The fruits are red or orange with yellow seeds inside and taste sweet but are not edible.
Type
Perennial Broadleaf
Family
Rosaceae
Control
For small infestations of Indian mock strawberries, hand pulling can be effective if done regularly. For larger populations, chemical control may be necessary; however, it’s best to use selective post-emergent herbicides as these will target the weed without damaging nearby desirable plants. Additionally, mulching around desirable plants can help prevent new weeds from coming through.
Lawn burweed
Lawn burweed is a winter annual weed that has small, white flowers and long pointed seed heads. Its leaves are narrow and needle-like, while its stems have a bristly texture. The leaves grow in an alternating pattern along the stem, giving it a “burr-like” appearance.
Type
Winter Annual
Family
Asteraceae
Control
To effectively control lawn burweed, it’s crucial to apply a post-emergence herbicide between December and February, during the winter months. This is because the weed is smaller in size and easier to manage during this period. Additionally, it has not yet developed spine-tipped burs, which further aids in controlling its growth.
Nutsedge
Nutsedge, also commonly known as Nutgrass, is a perennial weed with bright green leaves and sharp edges. It grows in clumps with yellow flowers that emerge from spikes or “nuts” located at the top of the plant. Nutsedge prefers moist soil and can spread rapidly throughout lawns.
Nutsedge might go unnoticed at first because its seeds look like out-of-season Bermuda grass and thatch.
Type
Perennial Grass
Family
Cyperaceae
Control
Regular maintenance is key when controlling Nutsedge. To achieve a healthy lawn, it is important to have proper mowing and watering schedules. Additionally, post-emergent herbicides can help target established weeds like Nutsedge. Be sure to apply the herbicide during the early stages of growth and follow up with another application as needed.
Sedges
Sedges are perennial grass-like weeds that form dense mats in lawns. They have narrow, hair-like leaves and grow in a triangular pattern. The leaves are arranged in three rows with one row of thickened stems at the center. Sedges can quickly take over turf if left unchecked.
Type
Perennial Grass
Family
Cyperaceae
Control
Preemergent herbicides are the most effective way to control sedges; however, post-emergent treatments may also be necessary for established populations. Be sure to apply the herbicide when the weed is actively growing and follow up with another application as needed. Additionally, keep lawns healthy by fertilizing regularly and pulling up the weed by hand.
Spurge
Spurge is a common warm-season weed, usually found in container nurseries. Its flowers are greenish-white. When its leaves or stems are broken, a milky sap exudes. There are several types of spurge including ground spurge and spotted spurge, which are almost similar, having prostrate to ascending stems carrying oblong or round leaves.
The weed species can be commonly found in grasslands, pastures, roadsides, and prairies. It survives in a wide range of soil types.
Type
Perennial
Family
Euphorbiaceae
Control
You can remove a small patch of spurge effectively by hand-pulling. However, the primary method of dealing with spurges is prevention, because controlling these weeds seems to be hard, especially when the plants have taken root. Various post-emergent herbicides can also be used to control spurge invasions in your garden or lawn.
Torpedograss
Torpedograss, scientifically known as Panicum repens, is a type of perennial plant that can grow up to 3 feet (1 meter) tall. It has long creeping rhizomes, which are horizontal underground stems, and its rhizome tips resemble torpedoes in shape. This fast-spreading weed can quickly take over turf if left unchecked.
Type
Perennial Grass
Family
Poaceae
Control
To control torpedograss, it is important to apply preemergent herbicides in early spring when temperatures reach 55°F (13°C). Additionally, post-emergent herbicides should be applied during the summer months when the weeds are actively growing. Regular mowing and watering can also help keep this weed at bay as long as any infestations are caught early on.
Virginia buttonweed
Virginia buttonweed is a perennial weed with multiple stems and small, white daisy-like flowers. The leaves are oval in shape and have a fuzzy texture on both sides. This weed can be difficult to spot when it is young because of its similar appearance to clover, which makes it easy for it to spread through lawns quickly.
Type
Perennial
Family
Asteraceae
Control
To control Virginia buttonweed, regular maintenance such as mowing and watering must be practiced throughout the year. Additionally, preemergent herbicides should be applied in early spring or late fall before temperatures reach 65°F (18°C). Post-emergent treatments may also be necessary.
White clover
While there are several types of clovers, white clovers are prevalent in Utah. You can recognize white clovers by their white, puffy blooms and leaves, which generally have a pale white “V” on them. The weed species grows low to the ground and is capable of quickly covering an entire lawn. White clover grows actively during late spring, summer, and autumn. It thrives in lawns that are nitrogen deficient.
Type
Perennial Broadleaf
Family
Apiaceae
Control
By maintaining the lawn properly, you can prevent the weed from growing and spreading. A pre-emergent herbicide application is recommended to control the white clover invasion and lawn weeds. For eradicating established weeds, it is important to use a post-emergent herbicide application.
Oxalis
Oxalis, also known as Yellow Woodsorrel or Sourgrass, is a low-growing weed with three leaflets that resemble clovers. Its flowers are white and can be seen in the summer months. Oxalis thrives in moist areas of your lawn and prefers full sun.
Type
Perennial Broadleaf
Family
Oxalidaceae
Control
Oxalis love compacted soil, so make sure to Core Aerate your lawn every year. The best time to apply post-emergent weed control is while the weed is actively growing.
