Weed: A plant that causes economic losses or ecological damages or creates health problems for animals or humans or is simply undesirable where it is growing. Crabgrass in a classic example.
Noxious Weed: Any plant designated by federal, state, or local government officials as injurious to public health, agriculture, recreation, wildlife, or property. Field Bindweed and Purple Loosestrife are classic examples. See a list of noxious weeds by state.
Invasive Weed: Weeds that are non-native invaders and therefore lack natural competitors or enemies to curtail their growth, which allows them to overrun native plants, displace species, and alter ecosystems. Classic examples are Kudzu and English Ivy.
“Weeds” aren’t inherently bad. Many weeds stabilize the soil and add organic matter. Some are edible to humans and provide habitat and food for wildlife, too. Weeds are also indicators of your soil’s health—or lack thereof. Find out what weeds can tell you about your soil!
10 Ways to Prevent Weeds Before They Become a Problem
Herbicides are an obvious and quick fix, but will not keep your weed problem from recurring year after year. For a healthy yard, you must address the cause.
The #1 rule with weeds is never let ‘em seed! Weed early, when the weeds are young. Some weeds produce tens of thousands of seeds from a single plant, multiplying your weed control problems for years to come. Get used to inspecting your garden daily. When weeds are young, just pull them out or cut them off below the soil line. Be careful to keep your digging shallow so that you don’t bring new weed seeds to the surface. Weeds are easily to remove when the ground is moist, such as the day after fresh rainfall.
Clean your gardening tools when you move from one area of the garden to another to avoid spreading weed seeds. Do not leave pulled weeds on the surface, either; discard in the trash.
Mow your lawn regularly to keep lawn weeds from producing seed. Mow off these green leaves!
Be careful when buying materials from garden centers. Ask for weed-free mulch, manure, compost, and soil. Read grass seed labels to make sure they don’t contain other crop seed.
If you have time (6 to 8 weeks BEFORE planting seeds), cover a weedy patch with landscape fabric, black plastic, or an old carpet. First, break up the top 4 to 8 inches of soil in your garden beds, rake it flat, and cover the soil. Then, avoid cultivating the soil to a depth greater than 2 inches. (Do this in fall, winter, or early spring when it’s not active gardening season.)
Once you’ve seeded, do not till a garden area if it’s filled with perennial weeds; you’ll only break up the underground tubers and spread weeds around.
Apply a layer of mulch! Weeds seeds have a harder time pushing through mulch, and mulch blocks sunlight
Water right around your plants; do not sprinkle your entire garden or you’re just watering your weeds.
In lawns, be careful not to over-fertilize or under-fertilize, as you’ll be promoting weed growth.
Establish a perimeter. Pay special attention to the area adjoining your flower beds, garden, natural area or lawn and establish a weed-free perimeter. Mow or mulch the area or pull or dig up weeds as they emerge. You’ll help to reduce the number of new weed seeds in the area you want to protect. Also, a good trimmer can make it easier to reach weeds along garden beds, posts, and tight spots.
Pay special attention to “perennial weeds” as identified in the list below. Perennial weeds (versus annuals) come back year after year and more difficult to control. You need dig up any roots, underground tubers, and rhizomes without leaving fragments behind. New weeds can grow from any pieces that break off and remain in the soil.
Cut off the emerged green part of the weed with your hoe or mower—repeating the process quickly each time it regrows. Without leaves needed for photosynthesis, the underground plant parts will become weakened and may eventually die.
If you dig out the weed, try to remove the taproot or as much as you can. You may be need to repeat several times.
When pulling out these weeds, wait until the soil is moist, and grasp low on the stem to avoid breaking it off.
With these techniques, you’ll soon find that you won’t spend much time weeding the following years!
13 Common Lawn and Garden Weeds
Below are some of the most common lawn and garden weeds. We have divided this list of weeds into two sections: 1) troublesome weeds, which compete with vegetables, fruits, and crops but may also have their own beneficial uses (in fact, many are edible plants or attract pollinators) and, 2) noxious weeds, which are so harmful to the ecology that they are prohibited or controlled by law on a federal or state level.
Remember: Only you decide what’s a weed and the consequences. For example, if you are trying to grow asparagus, you need to keep the bed weed-free or you will have a poor harvest. On the other hand, if you don’t mind your yard being taken over by dandelions, let it happen!
I. Troublesome Weeds
The following weeds are not noxious—but will spring up on their own in gardens and yards and are troublesome if not controlled. Again, you decide what is a weed. If you have these weeds amidst your vegetables and you want to keep them because of their nutritional content, just know that they will affect the yield of your intended harvest.
1. Crabgrass (Digitaria spp.)
Crabgrass is a low-growing, summer annual that spreads by seed and from rootings of nodes that lie on the soil. Undisturbed, it can grow to 2 feet tall.
This weed appears from mid-spring through summer when the ground is warm. It grows well under dry, hot conditions. As an annual, crabgrass dies at the end of each growing season—usually at the first frost in the fall—and it must produce new seeds every year.
How to Control Crabgrass Fortunately, crabgrass is fairly easy to manage. Controlling crabgrass before it sets seed is important because the seeds can remain viable for at least 3 years in soil.
In the lawn, mowing regularly is often all you need to prevent crabgrass from flowering and producing seed. Most experts recommend that you mow your lawn to a height of 2 to 4 inches and that you mow frequently enough to keep it within that range.
Also, if you keep a lawn, be sure to select grass adapted to your location so that it’s a healthy, thick lawn. Crabgrass loves a poor lawn. Because seedling crabgrass isn’t very competitive, a vigorously growing turf will crowd out new seedlings. Perennial ryegrass is the best competition for crabgrass. It also provides some insect control, as it emits a natural poison that gives some small, damaging bugs the “flu.” Fertilizing is key and must be done in the spring and in the fall.
Many herbicides for crabgrass aren’t that effective. Avoid using chemical herbicides in vegetable gardens because of the variety of crops grown and planted there. In gardens, you easily can control crabgrass by mulching, hoeing, and hand pulling when the plants are young and before they set seed. You also can control this weed with solarization. Finally, crabgrass thrives in compacted lawns, so work on aerating the lawn and this will go a long way.
Mulching with wood products (e.g. wood chips or nuggets), composted yard waste, or synthetic landscape fabrics covered with mulch will reduce crabgrass in shrub beds and bedding plants and around trees by blocking sunlight needed for its germination, establishment, and growth. If crabgrass is germinating in the mulch, move it about with a rake to reduce seedling establishment. Hand-pull escaped crabgrass plants before they set seed.
Is Crabgrass Edible? Technically, yes, but grasses are generally not the tastiest weeds out there! That said, crabgrass can be used as a forage crop for livestock and its seeds have historically been harvested as an edible grain.
2. Purslane (Portulaca oleracea)
Purslane is actually considered noxious in at least one U.S. state. Why is purslane, an annual succulent plant that’s edible, considered so troublesome? After all, it’s high in vitamins and even grown as a crop in some countries.
The answer goes back to the definition of weeds: Purslane can produce over 2,000,000 seeds PERPLANT! It reproduces by tiny black seeds and stem fragments in late spring, and it also can reproduce vegetatively through its leaves, making it especially tough to eradicate. Many a gardener has hoed purslane one day only to see it growing at full strength the next. So, unless you only want to grow purslane, think about how to control it.
How to Control Purslane In home landscapes and gardens, this summer weed is generally managed by hand-weeding. Keep an eye out for purslane! Pull out this weed as soon as you see it and destroy the plant; this weed can live in your soil for years!
Mulching is also helpful, especially in garden beds. To be effective, organic mulches should be at least 3 inches thick. Synthetic mulches (plastic or fabric mulch), which screen out light and provide a physical barrier to seedling development, also work well. Fabric mulches, which are porous and allow flow of water and air to roots, are preferred over plastics. Combinations of synthetic mulches with organic or rock mulches on top are commonly used in ornamental plantings.
Is Purslane Edible? Yes, you can eat purslane when it’s young and tender (assuming you’re not using chemicals in your garden). It’s a nutritional powerhouse and a great addition to a salad or stir-fry.
3. Lambsquarters (Chenopodium album)
Another edible weed! Lambsquarters is a fast-growing summer annual which is very nutritious and delicious steamed or in salads or juiced. But treasure the tender baby lambsquarters or they will get huge and truly be a troublesome weed. This summer annual broadleaf weed is a big problem in gardens and farms with sugar beets, vegetable crops, and pulse crops such as dry edible beans, lentils, and chickpeas.
Lambsquarters is a very fast-growing annual with seeds that are small and light enough to be blown by the wind over short distances. The seeds can sometimes even survive for decades in the soil. Under favorable conditions, these weeds can establish themselves quickly and spread profusely.
How to Control Lambsquarters This summertime weed rapidly removes moisture from soil, so remove it from unwanted areas as soon as possible! Cultivate lambsquarters out of your garden using a sharp hoe.
Is Lambsquarters Edible? Yes, you can eat lambsquarters (assuming you’re not using chemicals in your garden). In fact, their leaves are quite high in beneficial nutrients! The young shoots and leaves can be eaten raw in any vegetable dish, or sauteed or steamed like spinach. See our natural health blogger’s post on Anytime Salad.
4. Pigweed (Amaranthus spp.)
Image: Pigweed. Credit: United Soybean Board.
Pigweed wins the title of most “problematic” annual weed. It has evolved traits that makes it a tough competitor, especially in broadleaf crops like soybeans and cotton.
An annual weed that reproduces by seeds, pigweed is characterized by its fleshly red taproot. This weed appears in late spring or early summer and likes warm weather.
How to Control Pigweed Try to pull out this weed before it flowers!
Some weed seeds require light for germination and pigweed is one of those. To prevent pigweed in the future, cover your garden plot with a winter mulch.
Also, till very shallowly in the spring; only turning up a small amount of soil in order to keep those seeds buried. When you till, you may bring up some pigweed seed, so it’s best to mulch again. Cover the soil with five layers of wet newspaper and cover that with 3-6 inches of mulch.
Is Pigweed Edible? Pigweed is also edible—though only when young and tender (and when taken from a pesticide-free area). In June, the young leaves of Amaranthus blitum or amaranth are abundant and should be eaten because of their high nutritional content. Vitamin-wise, these greens are packed like carrots or beets and can be delicious in a tossed salad. You can also cook them as you would spinach. Some Native Americans traditionally used the black seeds of this plant as a ground meal for baking.
5. Chickweed (Stellaria sp. & Cerastium spp.)
Common chickweed (Stellaria media) is a winter annual that grows in well-watered areas. It’s a reservoir for insect pests and plant viruses.
When growing without competition from other plants, common chickweed can produce approximately 800 seeds and takes up to 8 years to eradicate. Chickweed thrives in moist, cool areas, so it often gets started before spring crops can become competitive. For this reason, it can limit your vegetable harvest.
Common chickweed often forms dense mats and rarely grows higher than 2 inches. The flowers are small with five white petals. Common chickweed will grow in a wide range of soils, but does particularly well in neutral pH soils with high nitrogen. It doesn’t grow as well in low pH (acidic) soils.
How to Control Chickweed Fortunately, annual chickweed is easier to control as long as you pull the weed when the plant is small and before it flowers. The challenge can be locating it during the short period between germination and flower production, so be sure to monitor closely and completely remove the weed so it doesn’t reroot.
Remember this is a “winter annual.” So, monitor the soil surface for chickweed seedlings throughout late fall and winter and then remove them by shallow cultivation or by hand pulling. By spring time, we would not recommend chemical controls for this winter annual.
Using a layer of organic mulch such as wood chips, at least two inches deep, will reduce the amount of weed seeds germinating by limiting light and serving as a physical barrier. Synthetic mulches such as landscape fabrics may also be used. In landscaped areas, they should be covered with an additional layer of mulch (rock or bark). Vegetable gardens can also utilize black plastic, both as mulch into which seeds or transplants are placed and also between rows.
Is Chickweed Edible? Chickweed is edible. When young, the leaves, stems, and flowers can all be eaten either raw or cooked. It adds a delicate spinach-like taste to any dish. Chickweed can also be a tonic and made into a tea.
6. Dandelion (Taraxacum officinale)
Ah, we love much about dandelions with their bright yellow heads in the springtime. This perennial weed forms rosettes of leaves with yellow flower clusters rising from the center. Bees can also find dandelions helpful though this plant is not a preferred food (and a poor quality source of protein). If you care about bees: Yes, a lawn full of dandelions is better for bees than a weed-free lawn, but not nearly as good as a garden with a variety of plants and no dandelions.
In addition, in time, dandelions will also take over any habitat from your garden to your ornamentals to your grasses. Not only do dandelions have wind-borne seed, but they also reproduce vegetatively thanks to large tap roots. So unless you cut the root deep into the soil, you can rest assured the plant will reemerge.
How to Control Dandelions Removing mature dandelions by hand-pulling or hoeing is often futile (unless done repeatedly over a long period of time) because of the deep tap root system of established plants. It’s best to pull young dandelions by grasping them firmly by their base and wiggling gently, as you must dislodge their deep taproot from the soil. Alternatively, use a hand trowel to dig them out. Try to remove the whole dandelion root at once, as any piece left in the ground will probably grow back.
If you keep a lawn, a vigorous (and competitive) lawn will slow down dandelion infestation. Dense turfgrass and ornamentals shade the soil surface, reducing the establishment of new dandelion seedlings. Many broadleaf weeds may be controlled with mowing, but this is NOT true of dandelion. Because it grows from a basal rosette that is lower than a mower blade can reach, mowing will have no effect on control.
For a garden bed, mulches of wood chips or bark are effective if they are maintained at a depth of least 3 inches deep (and replaced over time). Mulching with landscape fabrics can be particularly effective for controlling seedlings, reducing the amount of light that is able to reach the soil. Use a polypropylene or polyester fabric or black polyethylene (plastic tarp) to block all plant growth.
Solitary new dandelion plants along fence rows, roadsides, flower beds, and in turfgrass should be grubbed out (removed by digging out the entire plant, taproot and all) before they produce seed. Dandelion knives and similar specialized tools are available for removing individual weeds and their roots while minimizing soil disturbance. Monitor the area for several months to make sure that removal of the taproot was complete.
Are Dandelions Edible? Yes! If you cut the leaves of this perennial when they are young, you can enjoy tender greens in a salad. The wild ones in the spring are amazing! The flowers, too, can be eaten raw or fried, or used to make dandelion wine. Here are a few dandelion recipes to try: Dandelion Recipes. Be sure to leave plenty of dandelions for pollinators.
7. Shepherd’s Purse (Capsella bursa-pastoris)
Shepherd’s purse is actually a Brassica and part of the Mustard family along with cabbage. This flowering annual produces heart-shaped seedpods after flowering. It likes cool weather and its yellowish-brown seeds are long-lived in the ground.
How to Control Shepherd’s Purse Keep an eye out for its distinct leaves and pull out this annual weed by hand before it seeds. Be sure to remove the entire root.
Is Shepherd’s Purse Edible? The immature heart-shaped seedpods of shepherd’s purse have a peppery taste and can be used as garnish in moderation. Shepherd’s Purse also has a long history as a natural remedy for healing. Note: The leaves and mature seeds may cause indigestion and should not be consumed.
8. Creeping Charlie (Glechoma hederacea)
Creeping Charlie (ground ivy) and wild violet are common in shady lawns. Native to Europe, this perennial plant grows low to the ground in a vining habit, killing everything else around it. The plant has bright green leaves with scalloped edges on creeping stems (called stolons) that grow along the ground.
The reason Creeping Charlie is so challenging is the way it spreads—by both seeds and its creeping stems. If you try to dig it out and leave behind a fragment of rhizome (root), even a tiny piece can grow up as a new plant!
How to Control Creeping Charlie
Improve turf density by seeding grasses in shady areas which will help to limit this weed from spreading.
Also, make sure to grow the most suitable type of turfgrass for the location (e.g., plant shade tolerant turfgrass varieties under trees).
Improve soil drainage or water less frequently to dry the soil.
Mow regularly (to a height of 2 to 3½ inches), fertilizing and watering appropriately, and overseeding in the fall.
Pull out Creeping Charlie by hand if you only see a plant or two here or there. Try to pull the weed without breaking it and over time it may give up.
In heavily infested areas, the extensive spreading stems of creeping Charlie can be difficult to completely remove. If you have mats of weed, smother with a barrier of newspaper, tarp, or cardboard that will block all sunlight for at least a week. Once plants are pulled, make sure to dispose of the plants in such a way that they cannot re-root. Common herbicides do not work.
Is Creeping Charlie Edible? Prior to the mass cultivation of hops, Creeping Charlie was historically used in the brewing process of beer. As a member of the mint family, it has a slightly minty flavor and is often used by medical herbalists.
The noxious weeds (on federal and/or state level) on this list include field bindweed, quackgrass, Canada thistle, yellow nutsedge, and buckhorn plantain. There are other noxious weeds out there that are also problematic, such as Johnsongrass, but the ones listed here tend to be the most common.
9. Quackgrass (Elytrigia repens)
Quackgrass is a creeping, persistent perennial grass that reproduces by seeds. Its long, jointed, straw-colored rhizomes form a heavy mat in soil, from which new shoots may also appear.
How to Control Quackgrass Try to dig out this fast-growing grass as soon as you see it in your garden, being sure to dig up the entirety of the plant (including the roots). Dispose of in your waste bin rather than the compost pile, as it will likely continue to grow in the latter!
Is Quackgrass Edible? Not particularly.
10. Canada Thistle (Cirsium arvense)
Canada thistle is an aggressive, creeping perennial weed from Eurasia (despite its name). It infests crops, pastures, and non-crop areas like ditch banks and roadside. Canada thistle reduces forage consumption in pastures and rangeland because cattle typically will not graze near infestations.
This weed reproduces by seed and whitish, creeping rootstocks which send up new shoots every 8 to 12 inches. Plants reach 2 to 4 feet tall, grow in colonies, and reproduce asexually from rhizomatous roots (any part of the root system may give rise to new plants) or sexually from wind-blown seed.
The plant emerges from its roots in mid- to late spring and forms rosettes. Then, it will send up shoots every 8 to 12 inches. You may spots its purple flowers in July and August.
How to Control Canada Thistle Canada thistle is difficult to control because its extensive and deep root system allows it to easily recover from control attempts. Horizontal roots may extend outward 15 feet or more and vertical roots may grow 6 to 15 feet deep! Plus, seeds may retain viability 4+ years in the soil.
The first plants need to be destroyed by pulling or hoeing before they become securely rooted. Look for Canada thistle above ground in early spring.
If Canada thistle becomes rooted, the best control is to stress the plant and force it to use stored root nutrients. It’s at its weakest during the flowering stage in summertime; this is a good time to begin cultivation and destroy the roots and rootstock. One season of cultivation followed by a season of growing competitive crops such as winter rye, will go a long way toward eradication.
An approved herbicide, applied for two years in a heavily thistle-infested area, is an effective and limited control. Usually, a combination of techniques is needed. Consult with your local cooperative extension office.
Is Canada Thistle Edible? Believe it or not, Canada thistle is in fact edible—with some preparation required, of course. After the spines are meticulously removed, the leaves can be prepared like spinach. The stems are the most prized part, though their bristled outsides must be peeled first. Be sure to wear gloves!
11. Bindweed (Convolvulus arvensis)
Field bindweedis a hardy perennial vine that has been given many names, including perennial or wild morning-glory and creeping jenny. This noxious weed sprouts in late spring and becomes a huge problem in warm weather, when it spreads ruthlessly.
Note: Bindweed is NOT the same as the annual morning-glory (in the genus Ipomea) which has a larger (2-inch wide), showier flower and heart-shaped leaves.
An invasive from Eurasia, field bindweed is one of the most persistent weeds. The fast-growing root system grows right through the roots of other plants! And its roots are found to depths of 14 feet! Lateral roots form secondary vertical roots, anchoring the plant in place. A single field bindweed plant can spread radially more than 10 feet in a growing season. This extensive underground network allows for overwintering without foliage, and it can persist for up to 50 years in the soil.
How to Control Bindweed Unfortunately, tilling aids bindweed’s spread. Fragments of vertical roots and rhizomes as short as 2 inches can form new plants! The best control is prevention or early intervention. Seedlings of field bindweed must be removed before they become perennial plants within 3 to 4 weeks of germination. After that, perennial buds are formed and, by summer, it’s almost impossible to get all the roots.
Remember that each fragment of root will grow into a new plant, so use a garden fork to carefully pull out the entire root, including soil. Since bindweed grows through the roots of other plants, you may also need to lift your other perennials and plants!
Not everyone has a year to let a garden go fallow, but the easiest way to kill bindweed organically is to smother it from light with weed control fabric, black plastic, or old carpet; ensure that the edges of the covering overlap. Once the covering is removed, new bindweed plants might germinate from seed in the soil; monitor the site for new seedlings and hand-weed as needed.
Sometimes this perennial weed can only be killed with herbicides; this is more applicable to fields versus small home gardens. Speak to your local cooperative extension.
Is Bindweed Edible? No. All parts of the bindweed plant are poisonous. Do not ingest.
12. Nutsedge (Cyperus spp.)
Nutsedges are perennial weeds that superficially resemble grasses, but they are thicker and stiffer. Their leaves are arranged in sets of three from their base instead of sets of two as you would find in grass leaves. They are among the most problematic weeds for vegetable crops and can greatly reduce harvest yields. Yellow nutsedge has light brown flowers and seeds, while purple nutsedge flowers have a reddish tinge and the seeds are dark brown or black.
How to Control Nutsedge If you have nutsedge, it’s often an indication that your soil drainage is poor or waterlogged. However, once nutsedge is established, it’s very difficult to control.
The best approach is to prevent establishment of the weed in the first place. Remove small plants before they develop tubers. Tubers are key to nutsedge survival. If you can limit the production of tubers, you’ll eventually control the nutsedge itself. Most herbicides aren’t effective against tubers.
Also, eliminate the wet conditions that favor nutsedge growth. Use mulches in landscape beds. Landscape fabrics are the best mulch for sedges because the sharp leaves of nutsedge can find their way through other mulches.
Is Nutsedge Edible? Dating back to ancient Egypt, yellow nutsedge has historically been harvested for its tubers, which have a sweet, nutty flavor. Purple nutsedge tubers are also edible, but have a less pleasant, bitter taste.
13. Buckhorn Plantain (Plantago lanceolata)
Buckhorn plantain (also called English plantain or narrow-leaved plantain) is a common perennial weed most often seen in pastures, meadows, and lawns. This narrow-leafed weed reproduces and spreads by seeds.
How to Control Buckhorn Plantain Buckhorn plantain is low-growing, which makes it difficult to remove by hand. This plant’s long taproot makes it drought-tolerant and difficult to control, too.
So, to remove this weed, be diligent about pulling up young plants and destroying it before the plants go to seed. Learn how to scout and recognize young plants to help prevent early introductions from becoming persistent problems.
The best control is also preventative: grow a lush stand of plants so the surface of the soil is shaded and prevents new seeds from getting established. As a last resort, there are approved herbicides effective on buckhorn plantain to spray in the fall. Speak to your local cooperative extension.
Is Buckhorn Plantain Edible? Yes, this weed is edible, especially when the leaves are young and tender. Enjoy it raw, steamed, boiled, or sauteed.
We’ve gathered all of our best beginner gardening guides into a step-by-step series designed to help you learn how to garden! Visit our complete Gardening for Everyone hub, where you’ll find a series of guides—all free! From selecting the right gardening spot to choosing the best vegetables to grow, our Almanac gardening experts are excited to teach gardening to everyone—whether it’s your 1st or 40th garden.