What exactly is a weed?
The term “weed” means different things to different people.
According to the "Cambridge Dictionary", a weed is “any wild plant that grows in an unwanted place, especially in a garden or field where it prevents the cultivated plants from growing freely.”
Weeds can be found anywhere and everywhere. They can be native, invasive, noxious or none of the above. They’re in our lawns, gardens, pastures, fields and can even grow straight through concrete.
The five plants starring in Weeds: A Garden Takeover are considered pests across the United States, growing in unwanted places. And if left alone, they will take over your garden.
But there’s a reason these weeds thrive where they do.
Bindweed
Field bindweed, which has a similar flower to the ornamental morning-glory, is one of the most persistent and difficult-to-control weeds in the US. Mowing it or cutting off the flowers will not kill it because it can easily regrow from any piece left behind, thanks to its extensive root system.
Dandelion
Dandelions are an iconic early spring sight; its bright yellow flowers speckle green lawns and then turn into white balls of puff. Each plant can produce up to 20,000 seeds which are easily carried off by the wind. They can easily take over a yard, but being one of the first flowers blooming in the year makes them a critical food source for bees and other pollinators.
Hogweed
Giant hogweed may be in the same family as carrots, parsley, and cilantro, but it’s not something you want on your salad – or anywhere near you for that matter. Not to be mistaken for its close cousin, cow parsnip, its sap can cause your skin to blister when exposed to sunlight. Removing it will require personal protective equipment and possibly a professional.
Thistle
American goldfinches adore Canada thistle for food and nesting material. However, with its feathery seeds and aggressive root system, this spikey plant can and will take over an area, especially those with disturbed soils, like trails, overgrazed pastures, old fields, waste places, fence rows and along roadsides.
Milkweed
Though Monarch caterpillars rely on milkweed as a food source and cannot survive without it, some varieties, like common milkweed, can quickly grow out of control once established. However there are over 100 species of milkweed native to the United States, and only some of them grow like… well, weeds.
Why are so many weeds originally from other countries?
Many weeds are brought to the United States by accident. They might be introduced through human activity, birds, animals, wind, water or more.
When a new and aggressive species is introduced to an area, it may not have any natural predators or controls. It can spread quickly, taking over an area. Invasive species are often better at adapting to change than many native plants and can outcompete them early in the growing season.
While many invasive weeds were introduced by accident, some species were brought here on purpose.
Kudzu, also known as “The Vine That Ate The South,” originally came from Japan and southeast China and was brought to the United States first as an ornamental plant and then was actively promoted by the government as a “wonderplant” to control erosion. However, the sturdy vine will grow over anything in its path, smothering desirable plants under a thick blanket of leaves. It costs the forestry industry, utilities companies and even the national and state parks hundreds of millions of dollars every year to keep the invasive plant from covering everything.
Invasive phragmites, also known as the common reed, has also had a widespread impact on the United States ecosystem. This nonnative weed can be found along almost every waterbody in the United States. It was most likely brought on trading ships using soil as ballast to weigh down their ships until cargo could be loaded.
Though its origins are unclear, the common reed has many traditional uses across Europe, including roof thatching, water filtration and as a crafting material for basket weaving, paper and even musical instruments. It is a highly useful and versatile plant in its native environment but a noxious weed in the United States, where millions of dollars are spent annually on control and management activities across the country.
What can we do about weeds?
Weeds have overrun so much land that it is physically and financially impossible to get rid of them all. However, control is possible. Many government agencies and private organizations are actively managing noxious weeds like phragmites and kudzu and have published resources for how you can identify and help manage them yourself.
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When controlling weeds, the first step is to make sure you’re correctly identifying the plant. Education and rapid response can prevent new weeds from getting established, which reduces efforts down the road. Different weed species respond to different control methods and may require a combination of strategies for successful control. Get to know what’s considered invasive or noxious in your area.
Know your weeds
Actively maintain your lawn and garden beds
Use a combination of control methods and timing to manage the weeds in your yard. Don’t let weeds flower and seed. Remove the entire plant when you can, including all roots and mature seedheads, and dispose of them in trash instead of a compost pile. Some plants, like field bindweed, can completely regrow if even a little of its root remains. Others can send hundreds of seeds flying in a gust of wind.
Leave hitchhikers behind
The best way to fight the spread of weeds is to prevent them in the first place. Many weeds produce many tiny seeds, and some even have barbs, making it very easy for them to unknowingly attach to your shoes, clothes, gear, and pets. After hiking, camping or driving off-road, always check your pets and gear for seeds, mud and debris that you may have picked up. Make sure to properly dispose of all seed and plant material before leaving/entering each area you visit.
Plant native species when possible
Keep native plants on your property healthy and minimize soil disturbances. Plant native species on any bare areas to crowd out weeds, especially in areas that have just been reclaimed. Many invasive species have a native and more manageable counterpart that you can plant instead. For example, instead of common milkweed, plant less aggressive and native varieties like butterfly weed or whorled milkweed, which grow in clumps instead of spreading through rhizomes. Look at what’s local in your area before planting.
Get help from professionals
To manage difficult areas overrun by weeds, work with a natural resources professional or licensed private contractor who can help you create a control plan for removing and managing weeds on your property. The U.S. Department of Agriculture also provides technology and information to manage pest populations and their Noxious Weed Program seeks to prevent invasive plants from spreading or being introduced in the first place.
Miranda Lorenc
Technical Communicator
9/20/26