Grab your sprayers or herbicides, or be ready to tackle by hand some of the peskiest and most persistent lawn and garden weeds. 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.
1. 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.
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 preventes) that you can apply to your lawn in the spring. Even better would be a combination of lawn fertilizer and crabgrass preventer, which you can find in most home improvement and hardware stores.
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.
4. 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.
5. 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.
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.