Get out your herbicides and sprayers or prepare to take on some of the most stubborn and troublesome lawn and garden weeds by hand.

The best defense is one that is proactive rather than reactive.

The definition of a weed is not universally accepted. Some welcome the bright yellow dandelions, and those who rush to get rid of them before their expertly crafted seed factories have a chance to spread.

Weeds that creep into the grass and crack in the driveway or start a full-on invasion are examples of unwanted visitors that everyone can agree on.

Preventing weeds from taking root in the first place is the most excellent defense. Maintain healthy grass by removing any bare patches. To prevent seeds from reaching the soil, mulch around your garden plants and landscaping. The Weed Science Society of America recommends keeping your backyard compost hot enough to kill any weed seeds in grass clippings or leaves.

Weed control options include:

• Hand-hoeing.
• Using homemade or organic weed killers.
• Purchasing a commercial herbicide, should they take root.

A look at some of the most prevalent weeds and how to keep them under control.

Canadian thistle

Most of the continental United States and Hawaii consider the perennial, sometimes known as creeping thistle, to be noxious. The purple blossoms on these two-to four-foot bushes produce 1,500 to 5,000 seeds, which reseed or spread through their roots. Spiky leaves alone are enough to put them on your “no” list. Thistles can be controlled using various approaches, from pesticides to hand-digging.

Crabgrass

If you’ve ever seen a crab crawling down the border of a lawn, you know this plague of lawn perfectionists is everywhere. If you want to prevent crabgrass from forming on your property in the spring, there are several pre-emergence herbicides (sometimes called crabgrass preventers). A combination of lawn fertilizer and pre-emergence herbicides, found at most home improvement and hardware stores, would be even better for getting rid of crabgrass.

Dandelion

To make it simpler to remove the taproot from the ground, use a daisy grubber or weed puller if you can handle dandelions by hand. Dandelion blossoms may be used as a natural dye or for dandelion wine, while the leaves can be added to salads.

Spritz the leaves of the dandelions with vinegar, clove oil, or another organic spray on a dry day to get rid of them. It should take just a few hours for the leaves to wilt and become brown. The seeds of dandelions can be prevented from re-sprouting by bagging up dandelion cuttings before mowing the lawn.

Ragweed of the Fields

When the ragweed pollen season begins in mid-August, you’ll want to get rid of this feathery-leafed weed with tiny yellow flower clusters. Four-foot-tall plants prefer rich soil in partial or complete light and partial shade or full sun. Using a broadleaf herbicide (such as glyphosate) in late spring or early summer while ragweed is still tiny may remove it effectively. The best way to prevent it from flowering is to keep it mowed.

Boundary Weed

According to the Oregon Extension Service, bindweed may grow up to ten feet tall and have roots that reach a depth of nine feet, making it resistant to post-emergent herbicides. There is evidence that this plant is related to the morning glory family by the white (or pale blue or pink) trumpet-shaped blooms it produces. Even so, it’s considered hazardous by the EPA and is known for wreaking havoc in regions with poor soil and arid conditions. Find and remove the seeds with a garden fork or weeding tool.

Foxtail

The bushy seedhead of this annual grass, which resembles a fox’s tail and bounces atop the stem, is appropriately called. In either wet or dry soil, it flourishes. This weed’s most excellent protection is the same as crabgrass’: keep it out. With a pre-emergent herbicide or a mixture of pre-emergent and lawn fertilizer, you may get ahead of the game early in the year.

Lambsquarters

It is one of the most prevalent weeds found in the United States, reseeding each year in gardens where root crops and beans are grown. Scallop-edged trowel-shaped leaves with grey undersides can grow up to four feet tall. Prepare them for sautéing in olive oil by weeding them early in the season or collecting them. Spinach, according to foragers, does not contain as much calcium. If the weeds are taking over your yard but are not too close to your garden, you can use a herbicide that kills plants already grown.

Plantain

Weeds with rosette-shaped flowers like those found in calla lilies and Jack in the Pulpit can be found in many places. Plants of this perennial may yield 15,000 seeds and grow to a foot height when placed in a damp garden or yard. Apply a post-emergent herbicide to get rid of them.

Quackgrass

Perennial quackgrass enjoys chilly temperatures and produces wheat-like blooms. It’s widespread over the continent and may reach three feet in direct sunlight or partial shade. Your best defense against its rapid growth and multiplication is a frequent mow. Use an herbicide sparingly not to harm nearby grasses or plants while removing them by hand or pesticide.

Pigweed, Red-Rooted

This annual amaranth weed may grow up to six feet tall, with hairy clusters of green blooms. Some civilizations eat this plant or its seeds, but most backyard gardeners don’t want to risk an invasion because one plant produces 100,000 seeds. Post-emergent herbicides, such as glyphosate, may not be able to kill it, and they may have to be removed by hand.

The Nettle, the Stinging

If the soil is rich and wet, this invasive plant can grow up to five feet high. Most people associate it with painful welts, or an itchy rash caused by the spiky hairs on their arms and legs. Protect yourself from the sun by covering up your arms and legs. Protective gloves are required while pulling nettles from the ground. Use your garbage or yard waste collection provider to bag them up.

Creeping Charlie/Ground Ivy

The aggressive mint family is the source of this ubiquitous perennial groundcover with small purple blooms. As trees or shrubs mature and the sun-loving grasses underneath them begin to decline, they swiftly take over shaded spaces. After a rain, the dirt will be easier to remove by hand. When digging up a strand of Christmas lights, gently pull the vine to free it as you would. If any pieces are accidentally left on the ground, they will regrow. A broadleaf herbicide or black plastic sheeting can be used to eradicate a significant infestation. Grass that can grow in partial shade should be replanted in the area.