Prevention Provides the Best Defense
Not everyone agrees on what a weed is. One person may welcome sunny yellow dandelions, while others pounce to eradicate them before one of the plant kingdom’s most cleverly engineered seed machines do their thing.
We can all agree, though, that certain unwelcome invaders pop up among vegetables, creep into the lawn, wedge their way into driveway and sidewalk crevices, or launch a full-on invasion.
The best defense is preventing weeds from taking root in the first place. Keep your lawn lush and eliminate thin, vulnerable spots. Mulch around garden plants and landscaping to stop seeds from reaching the soil. The Weed Science Society of America recommends making sure backyard compost reaches a high enough temperature to decompose any weed seeds mixed in with grass clippings or leaves.
If weeds do take root, decide whether you’re willing to eradicate weeds by hand and hoe, experiment with homemade or organic weed killers or go for a commercial herbicide.
Here’s a look at some of the most common weeds and how to keep them from taking over.
Canada Thistle
Spiky leaves are enough to put these on your least-wanted list. With 1,500 to 5,000 seeds developing from the purple flowers on these two- to four-foot plants, they reseed or spread through their roots. The perennial, also known as creeping thistle, is considered noxious in most of the continental U.S. and even Hawaii. It takes persistence to get rid of thistles using a variety of methods from herbicides to hand-digging.
Crabgrass
Sprawling like a crab’s legs, this scourge of lawn perfectionists often pops up at the edges of a yard, fences and any place it can wedge into a scrap of open dirt. It’s common enough that there are plenty of pre-emergence herbicides (also called crabgrass preventers) that you can apply to your lawn in the spring. Even better for getting rid of crabgrass would be a combination of lawn fertilizer and pre-emergence herbicides, which you can find in most home improvement and hardware stores.
Dandelion
It you can tackle dandelions by hand, a daisy grubber or weed puller loosens the tap root to make it easier to pull from the ground. If you want to put the weed to use, add dandelion leaves to a salad and use the flowers as a natural dye or for dandelion wine.
To kill the dandelions, use vinegar, clove oil or other organic spray spritzed directly on the leaves on a dry day. Within a few hours, leaves should wither and brown. If you need to mow a dandelion-dotted yard, bag up clippings to keep the seeds from replanting.
Common Ragweed
If you’re among the 23 million Americans who are allergic to ragweed pollen that hits in mid-August, you’ll want to eliminate this feathery-leafed weed with tiny yellow flower clusters. It grows up to four feet high and prefers heavy soils in partial shade or full sun. Remove it by hand or use a broadleaf herbicide (glyphosate will work) in late spring or early summer when ragweed is still small. Keeping it mowed and unable to flower also will help.
Field Bindweed
This weed’s white (or pale blue or pink) trumpet flowers show its relation to the morning glory family. It’s classified as noxious, though, and is notorious for taking over areas with poor soil and dry conditions that might stress other plants. Bindweed can spread 10 feet in a single season and sink its roots nine feet deep, which helps it resist post-emergent herbicides, according to the Oregon Extension Service. Use a garden fork or weeding tool to find and pull the roots.
Foxtail
This aptly named annual grass features a bushy seedhead like a fox’s tail that bounces atop the stem. It thrives in moist or dry soil and grows quickly. The best defense if you’ve had a problem with this weed is similar to crabgrass: Strike in the spring with a pre-emergent herbicide or a combination pre-emergent and lawn fertilizer mix.
Lambsquarters
Among the most common weeds in America, lambsquarters reseed each year and seem especially common in gardens among root crops and beans. They can grow up to four feet tall with scallop-edged trowel-shaped leaves with gray undersides. Weed them early in the season or collect them to sauté in olive oil. Foragers claim they have more calcium than spinach. If they’re invading your yard and at a safe distance from your garden, you can try a post-emergent herbicide.
Plantain
There are several variations of these low-growing rosette-shaped weeds that shoot up a flower like you’d see inside a calla lily or Jack in the Pulpit. These perennials grow up to a foot tall in moist yards and gardens and can produce 15,000 seeds per plant. Pull these by hand or apply a post-emergent herbicide to knock them back.
Quackgrass
Perennial quackgrass likes cool weather and sprouts flowers that look similar to wheat. It ranges across the continent and grows to three feet tall in the sun or shade. You can mow it regularly to keep it from getting the nutrients it needs to multiply and thrive. You can also remove it by hand or use an herbicide while being careful not to affect surrounding grasses or plants.
Red-Root Pigweed
This annual weed from the amaranth family grows hairy clusters of green flowers and can stretch up to six feet tall in places. Some cultures will eat this plant and/or its seeds, but with one plant producing 100,000 seeds, most backyard gardeners don’t want to risk an invasion. It may have a resistance to post-emergent herbicide, such as glyphosate, and may need pulling by hand.
Stinging Nettle
Thriving in rich, moist soil, this invasive plant with sawtooth leaves grows up to five feet tall. It’s best known for its sharp hairs that can cause small welts or a miserable rash. Nettles need to be carefully pulled from the ground using protective gloves. Cover up your arms and legs, too. Bag them for your garbage or yard waste pickup service.
Ground Ivy/Creeping Charlie
This widespread perennial groundcover with tiny purple flowers is popularly known as Creeping Charlie and it comes from the aggressive mint family. It quickly carpets shady areas as trees or shrubs grow and sun-loving grasses beneath them begin to falter. Pull it out by hand when dirt is loose after a rain. Tug gently to get the entire vine as if you were unearthing a string of Christmas lights. Any sections left behind in the dirt will grow back. To tackle a large invasion, try a broadleaf herbicide or use black plastic sheeting to kill off all the plants. Replant the area with grass that tolerates semi-shade.