What Is Crabgrass?

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Crabgrass, an infamous weed, holds its place as one of the most persistent adversaries in the world of gardening. Its remarkable survival abilities allow it to thrive even in the most neglected garden beds and, surprisingly, within the cracks of walkways. Remarkably, there are over 35 distinct varieties of crabgrass globally. The large and smooth crabgrass varieties dominate the landscape as the most prevalent intruders in North America.

This blog will delve into the crabgrass world and unveil its resilience secrets. By learning about the diverse crabgrass types, you'll gain the upper hand in spotting the early signs of infestation, ultimately preventing it from conquering your cherished lawn. Join us as we explore the strategies of this unyielding weed and learn how to safeguard your garden from its tenacious grip.

Types Of Crabgrass

Crabgrass is a common lawn weed that is found in many parts of the world. An annual grass germinates in the spring, grows and produces seeds in the summer, and dies in the fall. Crabgrass is a warm-season grass, so it prefers warm weather and thrives in sunny areas with well-drained soil.

Though there are different types, they all look similar enough as crabgrass is a coarse, light green grass with flat blades and a sprawling growth habit. It is often mistaken for fescue grass, but a few key differences exist. Crabgrass blades are lighter in color and have a distinct veining pattern. Crabgrass also grows in a more clumpy fashion than fescue grass.

Short/Smooth Crabgrass

Short smooth crabgrass (Digitaria ischaemum) is a low-growing, summer annual grass found in lawns and other disturbed areas throughout the United States. It is a warm-season grass germinating in the spring when the soil temperature reaches at least 65 degrees Fahrenheit. It grows and produces seeds in the summer and dies in the fall.

Short, smooth crabgrass has slender, sprawling stems that can root at the nodes. The leaf blades are flat, smooth, and hairless. They are 1/4 to 1/3 inch wide and up to 5 inches long. The leaf sheaths are also smooth and hairless.

Large/Hairy Crabgrass

Large crabgrass is a low-growing summer annual grass that spreads throughout a region by seeds and nodes. It can grow up to 2 feet tall if not cut. Its flowers are arranged in clusters of 2 to 15 spike-like structures. The leaves on mature large crabgrass plants can be 2 to 10 inches long and about ⅔ of an inch wide.

Seedling leaves are light green and covered with tiny hairs. The hairs also cover the leaf sheath as the plant grows. Large crabgrass thrives in well-drained soil, including sandy soil, and can be found in lawns, roadsides, cracks in sidewalks, and even waste areas.

Southern Crabgrass

Southern crabgrass is a warm-season annual grassy weed most common on coastal plains and in the Southern United States. It has a similar growth pattern to smooth and large crabgrass, but with a prominent midvein. The leaf sheath of Southern crabgrass has the same long hairs as large crabgrass, but the leaf blades are rarely hairy.

Southern crabgrass can grow up to three feet tall and has long, thin, flat blades. It is often planted intentionally as a grazing crop for livestock.

Tropical Crabgrass

Tropical crabgrass, also known as Asian crabgrass, is a summer annual grassy weed that is most common in the warmer southern states. It produces seeds from midsummer until the first frost, which then go dormant over the winter and germinate the following spring. Tropical crabgrass can grow from summer to winter.

The leaves of tropical crabgrass can be as long as those of large and southern crabgrass, and its seed head branches all join at the same point on the stem.

Life Cycle Of Crabgrass

The life cycle of crabgrass varies depending on the species, but the general process is the same. Crabgrass is a warm-season annual grass, which means it germinates in the spring, grows and produces seeds in the summer, and dies in the fall.

The lifecycle of crabgrass is as follows:

  • Seed germination: Crabgrass seeds germinate in the spring when the soil temperature reaches at least 65 degrees Fahrenheit. The seeds germinate quickly, and crabgrass seedlings can emerge from the soil within a week of germination.
  • Seedling growth: Crabgrass seedlings grow quickly and can reach a height of several inches within a few weeks. The seedlings have long, thin leaves and a shallow root system.
  • Maturity: Crabgrass plants reach maturity in the summer. Mature crabgrass plants can grow up to 2 feet tall and have a wide, spreading root system. Crabgrass plants produce flowers in the summer, which are arranged in clusters of 2 to 15 spike-like structures.
  • Seed production: Crabgrass plants produce seeds in the summer and fall. The seeds are dispersed by wind and water.
  • Dormancy: Crabgrass plants go dormant in the fall when the soil temperature drops below 50 degrees Fahrenheit. The seeds remain dormant over the winter and germinate the following spring.

Controlling & Managing Crabgrass

crabgrass emerging

Crabgrass is a common lawn weed that can be difficult to control. Fortunately, there are a number of steps you can take to keep your lawn free of this pesky weed.

The best way to control crabgrass is to use a combination of methods. This includes using herbicides, proper lawn care, and cultural practices.


Several different herbicides are available to control crabgrass. Some herbicides are pre-emergent, which is applied before the crabgrass seeds germinate. Others are post-emergent, meaning they are applied to actively growing crabgrass plants.

When choosing an herbicide, select one that is safe for your type of lawn grass. It is also important to follow the directions on the herbicide label carefully.

Proper Lawn Care

A healthy lawn is less likely to be invaded by crabgrass. To maintain a healthy lawn, water regularly, mow at the correct height, and fertilize according to your lawn's needs. Practicing basic lawn care such as aerating your lawn will keep your turfgrass healthy and your lawn free of weeds.

Cultural Practices

There are a number of cultural practices that can help to control crabgrass. These include:

  • Mulching: Mulch helps to prevent crabgrass seeds from germinating.
  • Hand-pulling: Hand-pulling crabgrass plants can be effective, but removing the entire plant, including the roots, is important.
  • Overseeding: Overseeding your lawn with new grass seed can help to thicken your lawn and make it more resistant to crabgrass.