One of the most common lawn problems is the growth of broadleaf weeds. Two examples of a broadleaf weed are clover and dandelion. However, there are many more. To properly treat the broadleaf weed, know what you are dealing with. If you cannot decipher which weed you are dealing with from the descriptions on the back of herbicides, contact your local county service. Once you know your weed, you can begin extermination.
Mow your grass to the proper height for the species. Each grass has preferred height range. In the summer, keep your grass at the higher end of the range to help prevent burnout. This will make the grass stronger and more likely to choke out broadleaf weeds.
Select a liquid herbicide specially formulated for your specific broadleaf weed problem. Apply the herbicide on actively growing weeds in the early spring and early fall. Mid-summer applications are discouraged. If necessary, apply on a day when the temperature is expected to stay below 80 degrees F.
Apply the herbicide at least 24 hours prior to mowing or watering your lawn. Do not apply if there is rain in the forecast.
Spray the herbicide directly over the broadleaf weed. The weed will absorb the herbicide through its leaves. Take care not to get herbicide on nearby flowers, bushes or trees. A second application may be required 20 to 30 days after the first application.
Select a sunny, calm day with outdoor temperatures between 60 and 80 degrees F. Apply the herbicide on a day when rain is not forecast for two days following the application. According to the University of Minnesota Extension website, applying the herbicide in either mid-spring or early autumn will produce the most effective results. You may need to reapply the herbicide once per month to keep control over dandelions.
Spray the herbicide directly over the dandelion plant, thoroughly saturating the foliage, stems and blossoms.
Repeat the herbicide application if the dandelions still appear healthy in the grass one month later.
Dandelions (Taraxacum officinale) are broadleaf, winter perennial weeds with distinctive bright yellow flowers and large lobbed leaves extending from a single stem. Dandelions are best removed by hand-pulling from the base root.
Carpetweed (Mollugo verticillata) is a broadleaf, summer annual weed that is low growing with white flowers. Carpetweed is best removed using post-emergent herbicides during the initial stages of growth during mid-summer.
Broadleaf plantains (Plantago major) are a perennial, broadleaf weed with large, low-growing leaves extending outward from a central node. For removal, use a selective broadleaf weed herbicide in mid-spring immediately following germination.
Bermudagrass (Cynoden dactylon) is a grassy, perennial weed that is fast-spreading and highly invasive. Also used as a turfgrass in southern states, Bermudagrass does not mix well with other lawn grasses. Control Burmudagrass with specialized post-emergent herbicides.
Goosegrass (Eleusine indica) is a clumping, grassy, summer annual weed found throughout the south. Goosegrass growth is most rapid during periods of summer heat, and can be stopped using both pre and post-emergent herbicides.
Peppergrass (Lepidium virginicum) is a grassy, winter annual weed with multiple erect stems and green leaves. Post-emergent herbicides and hand-pulling are effective methods of removal.
Crabgrass is a broadleaf, annual, warm-season weed commonly found throughout Maryland. Crabgrass is a fast-spreading, opportunistic weed that grows best in warm summer temperatures and direct sunlight. Crabgrass survives the winter months as seed, sprouts mid-May and perishes during the first fall freeze.
Foxtail grass is a common lawn weed with coarse, broad leaves resembling Crabgrass. Foxtail grass forms flat, dense tufts and produces a large visible seed pod. Foxtail grass seeds germinate late spring and survive until the first freeze.
Goosegrass is a grasslike lawn weed with smooth, folded leaves commonly found interspersed with turfgrass. It is highly pernicious and opportunistic by exploiting bare patches in lawn grass. As a hardy weed species, Goosegrass is specially adapted to growing in dry, compacted soil environments.
Dandelions are one of the most widely occurring lawn weeds throughout Maryland and the rest of the United States. Dandelions are a perennial, herbaceous plant with distinctive arrow-shaped leaves and bright yellow flowers that blossom during the summer months. Dandelion flowers mature into globular seed pods containing thousands of individual seeds that are dispersed by a light breeze into the surrounding area.
Barnyardgrass (Echinoochloa crusgalli) is a grassy, summer annual lawn weed that is found in moist, nutrient-rich soils. Regular mowing will prevent the formation of seed pods and help to stem growth and spreading. Already established Barnyardgrass weeds should be hand pulled from the root or sprayed with a post-emergent herbicide.
Broadleaf plantain (Plantago major) is a broadleaf lawn weed found in northeast Pennsylvania between June and September. Broadleaf plantains have large, broad, fibrous leaves extending outward from a central stem. Removal is best accomplished by pulling the weed from the root.
Crabgrass (Digitaria sanguinalis) is a clumping, grassy, summer annual weed that germinates during the spring months in northeastern Pennsylvania. This lawn weed has low-growing, thin, rolled blades that extend outward from the base. Crabgrass is fast spreading and pernicious. Lawns should be treated with a pre-emergent herbicide prior to germination in the early spring.
Dandelions (Taraxacum officinale) are a winter annual, broadleaf weed with a large, distinctive yellow flower forming during spring and summer. Dandelions have deeply lobed leaves extending from the base and spread by underground root systems. Isolated dandelions are best removed by hand pulling.
The synthetic compounds 2,4-D and MCPA, the first herbicides, were invented by E.J. Kraus, a botanist at the University of Chicago, working with doctoral students J.W. Mitchell and C.L. Hamner at the USDA in Beltsville, Maryland. In 1943 and 1944, Mitchell and Hamner successfully tested 2,4-D as a way to kill dandelions in a lawn in Beltsville. After World War II, farmers used the compounds to control broadleaf weeds growing with cereals, corn and other grain crops.
Pour vinegar on the dandelions to kill the weeds. The dandelions will take the vinegar down to the roots. The plants are strong, and it might take a few applications to kill them all.
Pull on the dandelion at its base, near the ground. Pull slowly and firmly. If you have rich airy soil or sandy soil, you might be able to pull the weeds up now that the roots are weak. If they feel like they are about to break, stop pulling. You are going to have to pull them out of the ground with a little assistance.
Dig down into the ground to get the entire root system of the dandelion. Pulling from the top isn't always possible. Digging down into the dirt, loosens the soil and helps you remove them more easily. If you don't want to have large holes in the yard, try using a manual post hole digger, which will make a small hole straight down.
Sheep sorrel (Rumex acetosella) is a perennial weed with an aggressive root system that can quickly invade and choke out competing turfgrasses. With green, arrow-shaped leaves that extend from multiple stems, sheep sorrel is easily identified but difficult to remove.
Cinquefoil (Potentilla simplex) is a perennial weed that thrives in infertile soil conditions. Spreading by the use of above-ground runners that form nodes and new root structures, cinquefoil has bright yellow flowers and is often confused with wild strawberry.
Centella (Centella repanda) is a perennial weed that prefers sandy, moist topsoil. Low-growing and fast-spreading, centella has oblong, rounded leaves that point upward and inconspicuous green flowers that grow at the base.
Bindweed (Convolvulus arvesis) is a low-growing, perennial weed that forms dense mats that are difficulty to control. With broad, arrow-shaped leaves, bindweed has a deep, pernicious root system that can quickly out-compete established lawn grasses.
Beggarweed (Meibomia purpurea), often confused with common clover, is a perennial weed with woody stems and rounded, oblong leaves occurring in triplets. With flat, hairy seed pods that stick to animals and drop off in new locations, beggarweed is easily spread to home lawns and is much tougher to control than common clover.
Mow the lawn and the viney lawn weed as close to the ground as possible.
Wait for the viney lawn weeds to grow 4 to 6 inches. Perennial weeds like viney lawn weeds must be actively growing to transfer an herbicide like Roundup to their extensive root systems.
Mix the Roundup with water, according to the manufacturer's instructions, if necessary. However, most Roundup products for home use come premixed in easy-to-use spray bottles.
Spray the product on the viney lawn weeds. The spray should coat all of the plant's tissue, but should not be applied so heavily that the product runs off. Spray early in the morning or late in the afternoon when the sun is at its weakest.
Re-spray plants at 7 to 10 day intervals as needed (if the weed shows no sign of decline during this period). Re-spray any new growth as soon as it crops up.