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Types of Weeds: Identifying and Treating Weed Types

Have you ever wondered about the pesky plants that appear out of nowhere and take over your yard? If so, you’ve likely experienced the invasive and harmful consequences weeds can cause.

So how do you identify what types of weeds are bombarding your landscape, and how can you eliminate them?

Keep reading to learn about the different types of common weeds and what you can do about them.

Closeup of the flowers and heart-shaped seed pods of Shepherd's purse, one of the common types of weeds.
Shepherd’s purse.

Lambsquarters

A lambsquarters plant with green leaves, clusters of small white flowers, and purplish stems.

How to Identify Lambsquarters

Lambsquarters is an upright weed type that can grow five feet tall, depending on its habitat/terrain.

Its leaves are a distinctive feature of this plant. These leaves are usually covered with a white mealy coating in their early stages. As they mature, the color becomes dull and pale greenish-gray in color and the plant develops purple-tinged stalks.

The shape of Lambsquarters leaves can range from egg-shaped to long and thin with a tapered tip. The margins can be saw-toothed, wavy, or smooth during growth.

Once mature, the margins of the leaves become sharp-toothed and more triangular or diamond-shaped

When it’s fully grown, Lambsquarters begins to flower with small and inconspicuous buds. These buds first appear as light green clusters on the top of the stalk and later turn brown and papery as the seeds develop inside. At full maturity, these flowers will be dark brown or black with a shiny finish.

How to Get Rid of Lambsquarters

Unfortunately, the seeds of Lambsquarters can withstand pretty much any condition and are easily spread. Although difficult, removing these invasive plants in your landscape is possible.

Removing these plants as soon as you see them before they begin to produce seeds is important.

Large populations of Lambsquarters may be controlled by using herbicides with a specific ingredient called dicamba. This herbicide is more effective during the early stages of growth.

You can also apply a pre-emergence herbicide two weeks before planting your crops and a postemergence application if small weeds are caught early in their growth.

What Damage Does Lambsquarters Do?

Lambsquarters is generally a problem for gardeners and farmers growing corn and soybean crops. In large quantities, this weed can cause a loss of 50% of corn yield and up to 25% of soybean yield damage.

Additionally, this weed is toxic if ingested due to its oxalic acid contents. Eating in large quantities will result in sickness and death of sheep and pigs and can cause issues in the milk production of dairy cows. So keep this plant away from areas frequented by livestock.


Quickweed

Closeup of the serrated leaves and small white and yellow flowers of quickweed.

How to Identify Quickweed

Quickweed is easily recognized by its coarsely toothed oval-shaped leaves. It has small four or five-petaled flower heads with yellow disks and tiny white or pink petals.

This type of weed is often hairy-looking and nicknamed the “shaggy soldier.” It can grow up to two feet tall and is not to be mistaken for its toxic look-alike, Tridax, which is a ground-hugging plant.

How to Get Rid of Quickweed

Keeping Quickweed at bay involves a multi-faceted approach. The best method of getting rid of it is by scouting your fields regularly and hand-pulling the weed to eliminate it.

Make sure to discard the pulled weed into a bucket or other container because pulled seedlings can re-root.

You should also take steps to avoid spreading Quickweed if you already have it in your fields. Pressure washing your equipment will help make sure the seeds aren’t ending up in other fields.

Stale seedbeds can also be used to flush out Quickweed and other varieties before they’re fully established on your land. If stale seedbeds are an agricultural practice that’s new to you, here’s some more information to get you started on this process!

What Damage Does Quickweed Do?

As its name suggests, this weed’s biggest threat is its rapid growth. A single plant can produce up to 7,500 seeds in 6 to 7 weeks, resulting in a serious infestation.

If uncontrolled, Quickweed can dominate an entire field and kill nearby crops by out-competing them for nutrients and sunlight.


Puncturevine

The frond-like foliage and small yellow flowers of puncturevine.  Simiar-looking to chickpea plants.

How to Identify Puncturevine

In the early stages of growth, this weed has one large taproot with stems that form a mat-like cover on the ground. The leaves of Puncturevine form a pattern of five to eight oval leaflets on opposite sides of the stem from one another, and are usually hairy.

The flowers normally appear from July through October and have five bright yellow petals.

How to Get Rid of Puncturevine

Puncturevine is a type of weed that can be controlled long-term by reducing the number of seeds in the soil. This is best done by eliminating the plants before they can produce seeds (during or just before flowering). This process needs to be continued over several years.

Another weed-control method is removing Puncturevine by hand or with a hoe, making sure to get rid of any burrs that may have fallen off in the process. To remove it by hand, cut the plant from its taproot and continue to monitor the area, especially in the late spring and summer.

Shallow tilling can also be effective for large areas, but deep tilling is not recommended. If tilled further than one inch deep, you can increase the risk of burying seeds that can germinate for years after.

What Damage Does Puncturevine Do?

The seed capsules produce a bur that breaks into five seed capsules. These seed capsules are extremely sharp and make this weed especially unpleasant.

With deep taproots, Puncturevine aggressively competes for water and nutrients in fields and can greatly reduce the quality of hay products. If uncontrolled, this type of weed will become a thick mat that hides the sharp burrs and can create dangerous conditions for people, livestock, and pets.

Puncturevine is toxic to sheep and can cause light sensitivity, skin lesions, and swelling of their ears and lips. It can also contribute to nitrate poisoning, which causes loss of appetite, trouble breathing, and other harmful symptoms.


Orange Jewelweed

Closeup of bright orange flowers and leaves of orange jewelweed.

How to Identify Orange Jewelweed

Orange Jewelweed is a colorful type of weed that’s easy to identify. It has an interesting shape and is decorated with bright orange and red flecks that attract pollinators that help it spread.

This type of weed can grow up to eight feet and has scalloped, oval-shaped leaves. It may have fine hairs that line the lower surface of the leaves or no hairs at all.

The vibrant flowers grow where the leaf meets the stem as a single bloom or in clusters of two to three. After the flowers fade, the Orange Jewelweed produces shiny green seedpods that eventually split open and release seeds.

How to Get Rid of Orange Jewelweed

Because they’re annual growers, it only requires a few simple steps to reduce this weed’s population significantly. It’s critical not to let these weeds go to seed. You can prevent this weed from spreading by whacking or pulling the plants from the ground before the flowers open.

The Orange Jewelweed, luckily, is shallow-rooted, so it’s easy to pull out by hand. Make sure to lay down weed fabric, cardboard, or newspaper, and spread a thick layer of mulch to keep these weeds away.

Because seeds already in the soil can remain viable for several years, make sure not to disturb the area too much. This lowers the risk of bringing dormant seeds up that can germinate and further infest your area.

What Damage Does Orange Jewelweed Do?

Orange jewelweed is native to eastern North America and was originally introduced as a garden ornamental. It’s also called touch-me-not because if you touch the ripe seed pods, they’ll explode on the spot to scatter seeds.

This type of weed will invade disturbed areas and ditches and form dense stands when it grows wild. Because of its height, the Orange Jewelweed competes with shorter crops for sunlight and steals nutrients from the soil, causing nearby plant death.


Japanese Knotweed

Closeup of flowers and leaf of Japanese knotweed.

How to Identify Japanese Knotweed

This weed variety’s distinguishing feature is its clusters of cream-white flowers that bloom throughout the summer months. It has light green heart-shaped leaves that are spotted with red and purple flecks.

In this type of weed’s early stages, the leaves of the Japanese Knotweed are tightly rolled up and marked with dark red veins. When mature, its leaves can grow up to eight inches long.

The Japanese Knotweed grows upwards and can range from seven to nine feet tall. The stems grow in a zig-zag pattern and grow taller each day, especially in late spring to early summer.

Like the leaves, the Japanese Knotweed seeds are heart-shaped and have small wings. The outside of the roots are dark brown and have a yellow interior.

How to Get Rid of Japanese Knotweed

The best method of controlling the spread of Japanese Knotweed is through a combination of herbicides and cutting the plant from its base.

For best results, treatment should be completed in the late spring or early summer, followed by re-treatment in early fall. Patience is key, as getting rid of well-established colonies may take several years of treatment.

What Damage Does Japanese Knotweed Do?

Because of its competitiveness and ability to spread rapidly, this weed can cause environmental and structural damage to its surrounding areas.

The Japanese Knotweed tends to form clusters, which causes the weed to block sunlight from surrounding plants. Like other types of weeds, it also robs nutrients and water from the soil, leaving nearby plants to die.

This weed can also release chemicals from its roots that hinder other plants’ growth and decrease their ability to germinate.

The Japanese Knotweed is sometimes found in wet habitats, which causes even more problems. If located by a river shoreline, for example, the weed can enter the water and be spread by the current.

As it populates, the Japanese Knotweed will block the flow of water and increase the risk of flooding in the surrounding area. If the water can’t drain properly, it’ll overflow into nearby land, resulting in damaging floods.

As for other damages, when this type of weed is close to man-made structures, the underground stems may weaken the integrity of and destroy roads, sidewalks, parking lots, and much more.

Japanese Knotweed can split structures from their weakest points and damage underground conduits and septic systems, causing devastation throughout populated areas.

This is the Godzilla of weeds.


Common Groundsel

Closeup of the flower clusters of common groundsel. The telltale black triangle-shaped leaves at the base of the flowers are easily visible.

How to Identify Common Groundsel

The Common Groundsel is a semi-erect weed that grows a single stem and branches from the base. Its leaves are highly variable, making its identification a bit more challenging.

They can be hairless or lightly covered with long thin hairs. The lower leaves, connected to the stem with short stalks, are larger than the upper leaves, which attach directly to the stem without stalks.

This plant flowers year-round and produces small single yellow flowers that cluster into heads at the tip of the stem. A major distinguishing feature of the Common Groundsel is the bracts surrounding the flower head’s base. These leaflike structures are green with black tips. Eventually, the flowers turn into fluffy white circles resembling a dandelion.

The Common Groundsel also produces tiny, light brown-colored, cylindrical fruits that often appear hairy.

Being able to identify this plant is crucial. While look-alikes such as dandelion and annual sow thistle are edible, Common Groundsel is poisonous and shouldn’t be ingested. So look for those black triangle-shaped markings, and stay safe!

How to Get Rid of Common Groundsel

Common Groundsel infestations are more prevalent during cool and moist periods, as these plants die during extended dry and hot weather.

Eliminating this type of weed is generally easy and can be done by hand-pulling or using a hoe to cut it off at its taproot.

If you monitor your area regularly, you’ll be able to remove new weeds throughout the growing season to decrease their presence the next year. If the weed has invaded larger land plots, another effective weed-control method is rototilling or mowing young plants before they can flower.

What Damage Does Common Groundsel Do?

In addition to damaging crop fields, Common Grounsel also contains pyrrolizidine alkaloids that can poison humans and livestock when ingested in large quantities.

Although dangerous, livestock losses from feeding on this weed are not as common as you may think. Most poisonings are actually a result of the gradual ingestion of contaminated hay over an extended period of time.


Now You’re in the Know About Identifying Weeds!

Closeup of the stalk and bristles of a horsetail plant.
Horsetail.

It’s easy to be overwhelmed by weeds that have invaded your land and crops. However, identifying the weeds you’re dealing with and knowing how to remove them can give you and your garden the upper hand in the war against weeds.

Hopefully, this article was able to jump-start your weed identification and elimination journey!

Want to know even more about types of weeds? Check out our Common Weeds page for more information.