Weed Identification and Management

Controlling turfgrass weeds is crucial to the health of your lawn. Penn State Extension provides a comprehensive list of resources on turf weed management. In this section, discover best practices on identifying various weed species, using pesticides safely and preventing herbicide drift, and eradicating weeds.

Identifying Lawn Weeds

Lawn weeds are undesirable plants known for disrupting turf uniformity and competing with desirable grass species for nutrients. Developing an effective weed management program requires the ability to identify weed species and understand their life cycles.

The first step to lawn weed identification is distinguishing between grass weeds and broadleaf weeds. Broadleaf species – including black medic – bear colorful flowers of various shapes and sizes. Grass weeds, on the other hand, do not have flowers and leaf shapes are similar among species.

Depending on the life cycle, weeds can be annuals or perennials. Annuals, such as crabgrass and common chickweed, complete their cycle in one growing season. Perennials, like the common dandelion, can live for three or more years and produce new plants from seed.

Common Turf Weed Types

Moss is among the most persistent home lawn weeds. It typically grows where turfgrasses are thin and weak. A moss management program should begin with a soil test to determine nutrient content and needs. Chemical moss control options include products containing metals, salts, or herbicides.

In Pennsylvania, summer annual grasses are another pervasive weed problem. Common species include crabgrass, foxtails, barnyardgrass, and goosegrass. Controlling summer and annual grasses involves creating a dense turf through practices such as fertilization and proper mowing heights.

Other common lawn weeds include wild violet, field and corn speedwell, yellow nutsedge, and annual or daisy fleabane.

Lawn Care: Weed Management and Herbicides Application

For effective weed management, it is critical to implement cultural practices that increase the density and vigor of desirable turfgrasses. Cultural control measures include proper selection and establishment of turf, as well as adequate fertilization, liming, and watering.

Herbicides may also be applied as part of the lawn weed control program. It is recommended, however, to manage the health of lawns with minimal pesticide use through methods such as integrated pest management (IPM). IPM incorporates practices that help keep weeds and other pests below an established threshold level.

Find Resources on Lawn Weed Control

On this page, access recommendations on a wide array of weed lawn care topics. Information on the impact of mowing and drift-related damage is included, as well. Additional advice on turfgrass maintenance, aeration, and weed control can be obtained during Penn State Extension’s free turfgrass workshop.

Professionals can find further guidance in identifying weeds in turf and landscape situations, as well as controlling weeds in rights of way and industrial areas.