Herbicide Options for Managing Common Lawn Weeds in Maryland

Spray nozzle applying herbicide directly onto a dandelion growing in a lawn.

Target weeds with the appropriate type of herbicide based on weed type and stage of growth. Photo by Adobe Stock.

Updated: February 26, 2026

Herbicides are a type of pesticide used to control unwanted plants (weeds), and they have been used to control lawn weeds since the 1950s. The potential risks to people, pets, wildlife, and the environment should cause people to reconsider their use as part of routine lawn care. Reduce the need to rely on herbicides by concentrating on proper lawn care practices that help the lawn resist weed invasion. As with all pesticides, herbicide use should be a last resort and is not a substitute for good lawn care.

Critical herbicide information and precautions

Any pest, including weeds, should be identified before choosing a pesticide to control it. Identification helps you determine what herbicide is appropriate and effective on that weed, and what the weed's life cycle is (and when it may be most vulnerable to a herbicide application).

Look for a match in our Weed Identification Photos
The pesticide label is the law. Read and follow the label directions. The label information is for the safest and most effective use of that product. Learn more about herbicides for weed control from the National Pesticide Information Center.
Select ready-to-use (RTU) products to spot-treat weeds, eliminating the need for mixing a product to the right dilution rate and using a sprayer. If you choose to use a concentrate product, dedicate a sprayer for herbicide use only and do not use it for any fungicide or insecticide sprays.
Keep leftover herbicide in its original container. Try to purchase only the amount needed for only one season.
Herbicides work best on young weeds and when the weeds are actively growing. Do not treat drought-stressed lawns.
Late summer into autumn is a good time to treat difficult-to-control perennial weeds like creeping Charlie. Perennial plants move resources that were stored in their leaves, along with any chemical absorbed into those leaves, down to their root system as they prepare to go dormant for the winter.

Weed-and-feed products are not recommended because they are formulated to treat the entire yard (not individual weeds only), they are applied in spring (most lawn fertilizers should be applied in autumn), and their use can contribute to overfertilizing the lawn.

Problems with herbicide use

During certain weather conditions, volatility (the chemical is made airborne through evaporation) or drift (movement by air or water flow) can occur and cause damage to desirable plants.
Some herbicide active incredients may damage trees and shrubs when the ingredient is absorbed by roots growing in a treated lawn. Dicamba is a common example which is a component of several lawn herbicide products.
Herbicides, especially dry formulations like granules, can flow off of treated areas in irrigation or stormwater and injure plants downhill of those areas.
Herbicide can be accidentally tracked into homes by people and pets. Outdoors, synthetic herbicides are broken down by exposure to the sun, moisture, high temperature, and/or soil microbes. Indoors, the active ingredient can persist, increasing exposure to people and pets.
The relative effectiveness of herbicides is subject to many factors outside our control: temperature, rainfall, soil conditions, etc. Even when label directions are followed carefully, the resulting level of weed control may be disappointing.
Weeds can develop resistance to herbicides, making the applications less effective over time. The risk is greatest when the same active ingredients are used repeatedly on multiple generations of the same weed species over time.

Herbicide terms

Terms used on an herbicide label
Term	Meaning
Active ingredient	The chemical contained in the product that controls the target weeds. There can be more than one active ingredient, and there are many such combination products on the market. Inert ingredients are important for product application, shelf life, or other functions, but they do not directly control the weed.
Chemical name	A complex technical description of the active ingredient contained in an herbicide. There is only one chemical name used for each active ingredient. For example, the full chemical name for the ingredient commonly called 2,4-D is Dimethylamine salt of 2,4 dichlorophenoxyacetic acid. Example of a label with the active ingredient list.
Common name	A simpler version of the chemical name. There is only one common name for each active ingredient. 2,4-D is the common name for the chemical in the preceding above.
Trade name	A name used by the manufacturer of an herbicide for marketing purposes. Active ingredients can be sold under many trade names. For example, Roundup is a trade name, and the chemical glyphosate is often associated with that brand. However, not all Roundup products contain glyphosate, and not all products containing glyphosate are part of the Roundup brand.
Mode of action	A categorization of how the herbicide works in terms of how the plant is exposed and how broad or narrow the impacts of the ingredients are. Common distinctions include contact vs. systemic and selective vs. non-selective.
Contact	Affects only the portion of the plant tissue to which the herbicide was applied. It is not absorbed by the plant or moved within its tissues. Contact applications can "burn" or kill the tops of weeds, but they cannot kill the roots, rhizomes, or tubers of perennial plants. Vinegar and potassium salts of fatty acids are examples of organic contact herbicides. Contact herbicides are most effective against young, annual weeds, but are a poor choice for perennial weeds.
Systemic	Affects the entire plant by moving from where it was applied (usually the leaves) down into the roots. When applied in late summer or autumn, the herbicide moves more easily into roots, but any application could take weeks to kill the weed.
Selective	Affects certain plant species or groups without seriously harming others. Often used to control broadleaf weeds growing in a lawn without injuring the grass. Ingredient examples include 2,4-D, triclopyr, and dicamba.
Nonselective	Affects all plants contacted by the herbicide, whether they are broadleaved or grasses. Ingredient examples include glyphosate, diquat, and acetic acid (horticultural "vinegar"). Glyphosate is typically used in preparation for total lawn renovation. These are usually not used on grass as they also will kill desirable turf grass.
Pre-emergent	Prevents germination; applied before the emergence of a new generation of the weed. To be effective, pre-emergents must be applied before weed seeds sprout, and cannot be disturbed for a period of time after application (do not till or dig in the soil that disrupts the layer of treated soil). They are commonly used in the spring to control annual weeds like crabgrass.
Post-emergent	Targets weeds already growing; applied directly to the foliage of weeds that are beyond germination or which are regrowing from perennial roots. They can be selective or non-selective, and work more effectively when the weeds are actively growing and have not paused growth due to drought stress or seasonal dormancy.

Trends in residential herbicides

Manufacturers of lawn herbicides labeled for residential use are formulating more combination products - those with several active ingredients that can target a wider range of weeds. These combinations can include ingredients selective for grassy weeds as well as those selective for broadleaf plants, or pre-emergent ingredients added to post-emergent ingredients.

It is critical to read and follow the label directions of the product you select. Important label information includes: usage precautions (such as avoiding sensitive desirable species); the timing of application in relation to season as well as the weed stage of growth; the list of weeds controlled or prevented; where to use the product (home lawns versus golf courses may be one distinction); the dilution rate (if it's sold as a concentrate); if the application needs to be watered-in; how long to pause mowing; and if reseeding needs to be delayed for a period of time.

Organic lawn herbicides

Organic weed control products are non-selective, contact herbicides. They can also affect or temporarily discolor turfgrass. Organic herbicides are best applied to young weeds, and repeated applications will most likely be needed (according to the label directions) to fully control them.

Common organic active ingredients

Acetic acid (sometimes called horticultural vinegar, but as it's much more caustic than food-grade vinegar, this term can mislead people to assume a degree of safety when using it)
Botanical oils (such as clove, cinnamon, rosemary, and d-limonene)
Chelated iron (hydroxyethylenediaminetriacetic acid, HEDTA; learn more about iron-based herbicides)
Potassium salts of fatty acids (sometimes called horticultural soap)

Corn gluten can be used as an organic pre-emergent herbicide. It can suppress annual weeds like crabgrass, but is not as effective as conventional pre-emergent ingredients. However, corn gluten is a source of nitrogen, and therefore acts like a fertilizer as it breaks down. Applying corn gluten at the recommended rate to control weeds exceeds the amount of nitrogen allowed by Maryland's Lawn Fertilizer Law. For additional information about corn gluten refer to Corn Gluten for Crabgrass Control.

Synthetic (chemical) lawn herbicides

Pre-emergent herbicides for grassy weeds

Avoid using weed-and-feed products: they apply fertilizer at a time of year not ideal for the lawn, and may over-apply nitrogen (or apply it too early), either of which could violate the lawn fertilizer law. There are pre-emergent products on the market that do not include fertilizer. Look for them at garden centers, in farm supply stores, or in independent hardware stores.
Apply prior to weed seed germination. For crabgrass, germination begins when soil temperatures are above 55°F for several days. Japanese stiltgrass usually germinates slightly before crabgrass.
Water after application (according to label instructions) to move the chemical into the soil surface.
A second application may be possible or needed to continue control for late-sprouting weeds. Consult the label for any specific waiting period between herbicide application and overseeding turfgrass. (The ideal time of year to overseed fescue lawns is early autumn, but seeding can be done in spring if you need to repair or patch areas of damaged lawn.)

Examples of pre-emergent ingredients for grassy weeds

Dithiopyr
Pendimethalin
Prodiamine
Benefin

Post-emergent herbicides for grassy weeds

Post-emergent products are used for controlling perennial grassy weeds like bermudagrass, nimblewill, and roughstalk bluegrass. The leaf shape and growth habit of sedges and nutsedges make them look grassy, but they are not closely related to grasses, and herbicides that target grasses usually do not work on them (refer to the nutsedge herbicide section below).

There are not many effective options for selective chemical control of perennial grassy weeds without harming the turf in the process.
The conventional approach is to spray a lawn area infested with perennial weeds using a non-selective, systemic herbicide (such as glyphosate) to kill all of the vegetation. After spraying, wait a couple of weeks to see if the weeds are dead and not resprouting. One or more follow-up sprays may be needed before vigorous weeds fully succumb.

Examples of post-emergent ingredients for grassy weeds

Quinclorac
Fenoxaprop-p-ethyl

Pre-emergent herbicides for broadleaf weeds

Products often contain a combination of several active ingredients to control or suppress a wide range of common broadleaf weeds, such as chickweed, woodsorrel (Oxalis), hairy bittercress, and speedwell.

Isoxaben is an example of a pre-emergent ingredient selective for broadleaf weeds.

Post-emergent herbicides for broadleaf weeds

Check application weather restrictions on the product label. Usually, they should be applied only when daily air temperatures will be between 65° and 85°F. When the temperature is too hot, the herbicide will be more likely to volatilize and damage sensitive plants.
An application needs time to be absorbed into the leaves. Do not apply when precipitation is expected within 24 hours, unless the label notes the formulation is "weatherproof" after a shorter period of time. Similarly, do not mow for a few days prior to or after an application so the treated leaves are not cut off.
Consult the label for any specific waiting period between application and overseeding the lawn.

Examples of post-emergent ingredients for broadleaf weeds

2,4-D
mecoprop (MCPP)
MCPA
Dicamba
Triclopyr
Carfentrazone

Post-emergent herbicides for sedges and nutsedges

Yellow nutsedge and kyllinga are common lawn weeds that may be mistaken for grasses. A selective herbicide that targets sedges and nutsedges needs to be chosen to be effective. Active ingredient examples are Halosulfuron and Sulfentrazone.

Non-selective herbicide

A general-purpose herbicide will damage or kill any plant it is applied to, and may be necessary if there is no selective herbicide option that avoids damaging the lawn. Among synthetic herbicides, the most commonly-used systemic ingredient is Glyphosate. Lawns too inundated with weeds (especially hard-to-control species) may be more practical to renovate (start over) than spot-treat with more targeted herbicides. Avoid spraying the entire lawn in that situation - rent a sod stripper or hire a lawn company to manurally remove the lawn, if feasible - but when other methods fail, using an ingredient like glyphosate can strip the lawn of existing vegetation to create a "clean slate" for starting a new lawn.

Our goal is for all land stewards to learn and practice Integrated Pest Management (IPM) and select the least toxic solutions for suppressing pests if resorting to pesticides.

References to brands or trade names are for informational purposes only and do not constitute an endorsement or warranty by the University of Maryland. No discrimination is intended against products not mentioned. Herbicides and active ingredients mentioned are registered with the Maryland Department of Agriculture (MDA) for use in Maryland. Contact your local Extension Service for out-of-state pest management recommendations.

Home gardeners deal with many of the same pests (weeds, insects, and plant diseases) as commercial lawn care companies, nursery growers, arborists, and landscapers. However, some pesticides recommended for and labeled for professionals are not labeled or appropriate for the general public. Pest management practices and recommendations by UMD's Home and Garden Information Center are intended for general residential use in Maryland. Professionals providing lawn care and other home landscape management services should consult with local Extension Agents or regulatory agencies like the MDA.