You may recognize that a plant is a weed when it crops up on your lawn simply because it is out of place among the blades of grass. Deciding what it is may be a tougher matter altogether. Different kinds of weeds will invade your lawn from time to time, with some as common as dandelions and others as attractive as violets and buttercups, which are weeds nonetheless. These weeds include some wildflower species, some grass-like weeds and some pesky plants that stay prostrate to the ground as they attempt to conquer your lawn.
Many types of weeds that also qualify as a wildflower species can grow on your lawn, with many starting at your lawn's borders and eventually expanding their range if you are not vigilant. Among the most prolific are wild violets, a broadleaf plant that can grow in very dense clusters. Queen Anne's lace is a much taller threat, with stalks as high as 4 feet. Yarrow, despite its attractive smell, can inch onto your lawn. Hop clovers, white clovers and filarees are pleasant looking flowers that double as weeds in a lawn setting. You may hear mallows called "cheeses," as the seeds grow in a cheese-shaped round disc. They have whitish flowers and can develop in a new lawn as well as older one. Buttercups and dandelions both produce yellow flowers, but you will notice they can take over your lawn in short order, especially dandelions, with their deep taproot and plentiful seeds.
From the Pacific Coast east to New England, quack grass is a serious lawn weed, growing as high as 2 feet and resembling wheat. Some people consider Bermuda grass a pest on their lawns, while others actually encourage its growth, especially in parts of the South. Goosegrass frustrates many lawn owners, thriving in rich soils as well as poor and frequently growing next to paths and along driveways. Crabgrass acquires its moniker from its spreading stems that arch out from its center, making it look like it will rise up and scurry away. It takes over bare spots in a lawn and quickly entrenches itself. Nutgrass is hard to get rid of once it gets on a lawn because it grows from tubers that will reproduce even when you mow them down.
Certain weeds grow low to the ground on your lawn, spreading out and sometimes forming thick mats. Knotweed is one, capable of springing up even through hard-packed soil such as in a driveway. One look at carpetweed and you will never wonder why it has that name, as its leaves and stems, which are in a whorled pattern, grow in compact mats. Carpetweed does especially well in sandy soils. Purslane hails from Europe but it is an unwelcome visitor from abroad, known for its ability to grow from the broken off segments of its stems. Chickweed prefers the shady sections of your lawn, growing and spreading from a central point outward. Spruges are a dual-threat weed, ruining your lawn's looks and causing irritation to your skin with the juice from its stems.