9 Fast-Growing Weeds to Remove ASAP Before They Spread

Bindweed

With its white and pale pink flowers, bindweed (Convolvulus arvensis), also known as field bindweed, looks like a wild morning glory, though it does not belong to the same genus. But those delicate-looking perennial vines are classified as an invasive and noxious weed in many U.S. states.

Bindweed is wiry and strong and spreads by seeds, roots, and rhizomes. Removing the vines once they have twined around your snapdragons, dahlias, or zinnias without damaging your flowers is tricky. You may not notice bindweed until it has begun to climb. Unwind it gently from your garden plant, then pull from the base. If you cannot remove it with its root, break it off at the base. It won’t kill the weed, but it will keep it from continuing to strangle for a while.

Canada Thistle

Despite the name, Canada thistle (Cirsium arvense) is native to Europe. Canada thistle is a tall perennial plant that is highly invasive and will spread aggressively. Like all other non-native thistles, it should be pulled as soon as possible, not only to remove the ouch factor from your yard, but also to prevent the plants from developing a giant root system and spreading by root and seeds.

Yank thistles while they’re still in the rosette stage, before they get tall and bristly, and always wear gloves when handling the plants. If you don’t have time to pull all the thistles in your yard, at least cut them down when they flower to prevent them from going to seed.

Crabgrass

Crabgrass (Digitaria spp.) is an annual that spreads quickly. In early summer, crabgrass looks bright green and is rather small, but after a few weeks, you’ll find it as a large, spidery mess with stems running in all directions and quickly forming a dense mat.

Pulling crabgrass is easy when it is small, but once it gets large, it’s tough to get all the roots, especially in compacted soil. Pull larger crabgrass after a rain, and use a dandelion puller to loosen it up from below. 

Fortunately, mulching is very effective if done immediately after weeding out young crabgrass. Even a thick layer of grass clippings right over a newly sprouted carpet of young crabgrass works to suppress its growth. Only a few plants pop through the mulch, and those are easy to spot and deal with.

Nightshade

Commonly called bittersweet or woody nightshade (Solanum dulcamara), this perennial plant in the tomato family has pretty purple flowers, but it is highly toxic and doesn’t belong in gardens. The berries look appealing and tasty, which makes the plant dangerous for children (or even unsuspecting adults). Nightshade climbs and vines around, choking your other plants. Pull this weed as soon as you find it, and take care to dispose of it safely.

Pigweed

Pigweed (Amaranthus spp.) doesn’t spread especially quickly, but this perennial weed quickly grows into a large plant. It competes for nutrients and sets seed heads in midsummer when it’s hiding in your squash, zucchini, pumpkins, or flowers. Before flowering, the vegetative portion of the plant resembles the desirable amaranth grown for flowers and seeds.

Pigweed is excellent at camouflaging itself, and once it sets seed, it does so quickly. Pull it early if you can and make it a priority anytime you see one popping up and flowering in the late summer garden. When pigweed is young, hoeing is often all that is needed to kill it, but due to the deep taproot, established older plants are difficult to remove.

Quackgrass

Quackgrass (Elytrigia repens) is a notorious invader of garden beds, spreading via seeds and rhizomes. If you pull this weed correctly, you’ll often get a foot-long piece of root. There is always more that will sprout from a piece of rhizome and become a new weed. 

Remove quackgrass as soon as you can, and do it repeatedly. Hand pulling is best, because chopped-up rhizomes will often sprout several new plants. Its perennial nature means energy is stored in the roots, so you’ll be fighting this one for a while if you let it establish.

Stinging Nettle

Stinging nettle, also called common nettle (Urtica dioica), is a fast grower, but usually doesn’t take over in the garden. However, the pain of a nettle rash makes it worth pulling as soon as you find it. This perennial rapidly establishes on disturbed sites, such as construction lots, behind barns, or in fallow fields. They’re talented at popping up unnoticed among your flowers and vegetables, and giving you a painful surprise when you brush up against them.

While many people enjoy using common nettles for tea or cooked as a leafy green, it’s also a valuable addition to your compost pile. Wear gloves when pulling the plants, and if the plants are taller, wear long sleeves as well.

White Clover

There are reasons to leave white clover (Trifolium repens) in your lawn in early summer when it flowers because the bees love it. Because this perennial forms mats and sends out runners, a clover lawn makes a great alternative to conventional turfgrass. However, it is especially adept at sneaking into any bed bordered by lawn. When pulling it, start gently and lift at the base to find and expose runners, and remove as many of them as possible as well.

Yellow Sweet Clover

This one (Melilotus officinalis) tends to sneak up on you. It grows at the edge of a bed, near a stake or post, or around a taller plant where it has hidden until it gets large. Like many weeds, it prefers disturbed soil, such as our gardens, roadsides, or exposed banks. It is a biennial plant that flowers in its second year, then dies.

Yellow sweet clover has wiry stems and grows 3-6 feet tall if left unchecked. It can entangle other plants and suffocate them. Once large, it becomes difficult to remove without damaging nearby flowers or vegetables, so pull it early.