Lawn weeds: identify them and get rid of them without killing your grass

Contents

1. What kind of weed is in my lawn?
2. Types of lawn weeds: the common ones by group
3. Grassy weeds: why they are the hardest to kill in grass
4. Broadleaf weeds: the easiest to kill without hurting grass
5. Sedges: the grass look-alikes
6. Creeping lawn weeds
7. What your weeds say about your lawn
8. How to get rid of weeds in grass, step by step
9. Best weed control for lawns: products by job
10. Stopping weeds before they start
11. Common mistakes with lawn weeds
12. Lawn weed guides
13. FAQ

Most weed problems in grass come down to the same cause: bare or thin spots where light reaches the soil. A weed is an opportunist. Crabgrass needs sun on bare soil, creeping Charlie thrives where shade has thinned the lawn, nutsedge takes over spots that stay wet, and clover moves in where the grass is short of nitrogen. Treat the weed and the condition behind it, and lawn weed control gets easier every year.

What kind of weed is in my lawn?

Before you buy anything, put the weed in the right group. A broadleaf weed killer will not touch crabgrass, and a crabgrass product will not stop nutsedge. Three quick checks are enough:

1. Look at the leavesNarrow leaves with parallel veins, growing from a sheath around the stem, mean a grassy weed. Wider leaves with a branching network of veins, often with showy flowers, mean a broadleaf weed.
2. Roll the stem between your fingersA grass-like plant whose stem feels triangular is a sedge. Nutsedge leaves are also glossier and stiffer than lawn grass, and they grow faster, so the plants stick up a few days after you mow.
3. Note the season and the life cycleAnnuals sprout from seed, live one season and die; perennials come back from roots, runners or tubers year after year. A weed that appears in midsummer is often a summer annual; one that is green in early spring before your lawn wakes up may be a winter annual or a perennial.

If you still are not sure, our weed identification guide walks you through leaves, flowers and growth habit, with look-alikes for each common weed.

Types of lawn weeds: the common ones by group

This table covers the weeds you are most likely to find in US lawns, when they show up and what controls them best. Timing and products vary by region and grass type, so check the label before you treat.

Grassy weeds: why they are the hardest to kill in grass

Grassy weeds are grasses growing where you do not want them, which is exactly why they are tricky: anything that kills them can also hurt your lawn. They split into two groups.

Annual grassy weeds such as crabgrass, foxtail and goosegrass come back from seed every year. They are the easiest to prevent: a pre-emergent herbicide applied before the seeds sprout stops most of them, and a dense lawn shades the soil so fewer seeds germinate. Once up, they can be killed with grass-selective products while they are young.

Perennial grassy weeds such as quackgrass, nimblewill, bermudagrass in a cool-season lawn, or clumps of tall fescue in a bluegrass lawn are harder. Few selective products touch them, so university extension services usually recommend digging them out or spot-treating with a non-selective herbicide such as glyphosate, then reseeding. In Florida and the Gulf Coast, torpedo grass is a notorious example. Crabgrass and foxtail die at the first hard frost; a coarse grass that stays green through winter is a perennial and needs a different plan.

Broadleaf weeds: the easiest to kill without hurting grass

Broadleaf weeds are the dandelions, clover, violets and creeping weeds most people picture. Because their biology differs from grass, selective products can kill them in an established lawn. Most lawn broadleaf herbicides combine two or three active ingredients, typically 2,4-D, MCPP (mecoprop) and dicamba, because no single one controls every weed. Tougher creeping weeds such as creeping Charlie and wild violets respond better to triclopyr. Our broadleaf weed killer guide matches each weed to the ingredients that work on it.

Timing matters more than the product. Perennial broadleaf weeds are easiest to kill in early to mid-fall, when they send sugars down to their roots for winter and carry the herbicide with them. Winter annuals like chickweed and henbit are best treated while young, in fall or very early spring, before they flower.

Sedges: the grass look-alikes

Yellow nutsedge is the sedge most homeowners meet. It looks like a light green, shiny grass that outgrows the lawn after every mowing and forms patches in wet spots. Each plant produces small underground tubers, so pulling mature plants often leaves tubers behind to sprout again. Grassy-weed and broadleaf products do not control it; halosulfuron and sulfentrazone do, applied early, while plants have 3 to 5 leaves. Full details in our nutsedge guide.

Creeping lawn weeds

Some lawn weeds spread sideways on runners, stolons or rhizomes, rooting as they go: creeping Charlie, white clover, wild violets, prostrate spurge and oxalis are the usual suspects. They are frustrating to pull because every stem fragment left behind can start a new plant. For small patches, loosen the soil and lift the whole mat, following runners to their ends. For larger areas, a selective herbicide works better than hand weeding, and two applications a few weeks apart are often needed. Oxalis is easy to mistake for clover: its leaflets are heart-shaped and its flowers are yellow.

What your weeds say about your lawn

Many weeds are indicator plants. Fixing the condition is the longest-lasting form of weed control:

• Crabgrass, spurge, purslane: thin turf in full sun, mowing too short, light and frequent watering.
• Clover: low nitrogen; clover makes its own, so it stays green when the grass is hungry.
• Creeping Charlie, violets, moss: shade and moist soil where grass struggles.
• Plantain and knotweed: compacted soil along paths and play areas.
• Nutsedge: wet, poorly drained soil or overwatering.
• Moss: shade, poor drainage, compaction and often acidic soil.

How to get rid of weeds in grass, step by step

1. Identify the weed and its groupGrassy, broadleaf or sedge, annual or perennial. This decides the method, the product and the season.
2. Remove a few weeds by handPull or dig a day after rain or watering, when roots slide out whole. Use a long, narrow weeding tool for taproots like dandelion. Bag anything that is flowering or has seed heads.
3. Spot-treat instead of blanketing the lawnWhen weeds are scattered, spray only the weeds with a selective product labeled for your grass. Save broadcast applications for lawns where weeds are everywhere.
4. Match the timing to the weedSpring pre-emergent for crabgrass and foxtail, early summer for nutsedge, fall for perennial broadleaf weeds. Our weed control calendar lays out the year for northern, transition-zone and southern lawns.
5. Read the label and the weatherMost lawn herbicides work best on actively growing weeds, in moderate temperatures, with no rain for about 24 hours and little wind. Many labels warn against spraying above 85 °F. Do not mow for a few days before and after spraying so the weeds have enough leaf to absorb the product.
6. Fill the gapsOverseed or patch bare spots once the label's waiting period is over, so new weeds have no room. Late summer to early fall is the best seeding window for cool-season lawns.

The label is the law: every herbicide label lists the weeds it controls, the grasses it is safe on, the rate, the weather limits and how long to keep kids and pets off. Some lawn products injure St. Augustine, centipede or newly seeded grass, so read it before you buy, not after.

Best weed control for lawns: products by job

There is no single best lawn weed killer, only the right one for the weed in front of you. Here is the short version; our lawn weed killer guide covers each type in depth.

Weed-and-feed products combine fertilizer with a herbicide. They are convenient, but the best time to feed and the best time to kill a given weed rarely line up, so many extension specialists prefer separate products applied at the right moment for each job. If you want to avoid synthetic herbicides, read our natural weed killer and pet-safe weed killer guides; household vinegar and boiling water kill grass as readily as weeds, so keep them for spot use.

Stopping weeds before they start

A pre-emergent creates a thin chemical layer in the top of the soil that kills seedlings as they sprout. It does nothing to weeds that are already growing, and most products also stop grass seed, so do not apply one where you plan to seed this season unless the label allows it. Timing is everything: too late and the crabgrass is already up.

The cultural side does more work over the years:

• Mow high. For most cool-season lawns, 3 to 4 inches. Taller grass shades the soil, and crabgrass seed needs light to germinate. Never remove more than a third of the blade at once.
• Water deeply and less often. About an inch a week, in one or two sessions, grows deep grass roots. Light, frequent watering favors crabgrass and nutsedge.
• Feed on schedule. A soil test tells you what your lawn needs. Fall feeding is the most important for cool-season grasses.
• Fix compaction and shade. Core-aerate compacted areas and thin tree canopies, or switch to shade-tolerant grass or ground cover where grass will never thrive.
• Overseed thin spots. Bare soil is an open invitation; fill it with grass before weeds fill it for you.

Common mistakes with lawn weeds

• Using the wrong product for the weed group: broadleaf killers on crabgrass, crabgrass products on nutsedge.
• Applying a pre-emergent after weeds are up, or putting it down the same week you seed.
• Spraying in heat or wind: above about 85 °F many products injure turf or drift onto garden plants.
• Treating perennial broadleaf weeds only in spring, when fall would have reached the roots.
• Mowing right before or after spraying, which removes the leaves that need to absorb the product.
• Killing weeds and leaving bare soil: the gap fills with new weeds within weeks.
• Using salt, bleach or strong vinegar in the lawn: they kill grass, and salt stays in the soil. See why in our bleach weed killer guide.

Lawn weed guides

FAQ

What kills weeds but not grass?

A selective herbicide that is labeled for both the weed and your grass type. Broadleaf products built on 2,4-D, MCPP (mecoprop), dicamba or triclopyr kill dandelions, clover and other broadleaf weeds without harming most established lawn grasses. Grassy weeds need a different product (quinclorac, fenoxaprop, mesotrione or topramezone), and sedges need halosulfuron or sulfentrazone. Some grasses, such as St. Augustine and centipede, are sensitive to certain ingredients, so check the label for your grass. See our lawn weed killer guide.

What are the most common lawn weeds?

Across the US, the weeds that show up in most lawns are crabgrass, dandelion, white clover, creeping Charlie (ground ivy), plantain, chickweed, henbit, prostrate spurge, wild violet and yellow nutsedge. Which ones you get depends on your region, grass type, shade, soil and mowing habits.

How do I identify a weed in my lawn?

Start with three checks. Is the leaf grass-like with parallel veins (grassy weed), wide with a net of veins (broadleaf), or grass-like on a stem that feels triangular when you roll it (sedge)? Does it grow in clumps, rosettes or creeping runners? And when did it appear: spring, summer or fall? Those answers narrow it to a handful of suspects; our weed identification guide takes it from there.

When is the best time to treat lawn weeds?

It depends on the weed. Stop crabgrass and other summer annual grasses with a pre-emergent in early spring, before soil reaches about 55 °F for several days. Treat perennial broadleaf weeds such as dandelion, creeping Charlie and violets in early to mid-fall. Treat nutsedge in late spring to early summer while plants are young. Our weed control calendar shows the month-by-month plan for your region.

Should I pull lawn weeds or spray them?

Pull or dig when you have a few weeds and the soil is moist, especially young annuals and taprooted weeds like dandelion. Spot-spray a selective product when weeds are scattered across a large area or spread by runners that break when pulled, such as creeping Charlie. Broadcast spraying the whole lawn only makes sense when weeds are everywhere.

Will weeds come back after I kill them?

Usually, unless you fix the reason they moved in. Weed seeds stay alive in the soil for years and sprout wherever turf is thin. A dense lawn mowed at the right height, watered deeply and fed on schedule is the long-term fix; herbicides only buy you time to thicken the grass.

Related

• Lawn weed killerWeed killer for lawns, explained: selective vs non-selective, pre- vs post-emergent, liquid vs granular, grass type limits and the right ingredient by weed.
• Weed control calendarThe best time to spray weed killer by weed, season and region, plus the weather rules on the label. Pick your region for this month's lawn to-do list.
• Weed identificationWeed identification made simple: grass, broadleaf or sedge, leaf shape, flowers and growth habit. Use the free weed identifier, then get the fix for each weed.
• Pre-emergentA pre-emergent herbicide stops weed seeds before they sprout. Which active ingredient to choose, when to apply it by region, and how to water it in.

Updated October 3, 2026