What Is Crabgrass?

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How to identify crabgrass (1)

Crabgrass is an annual grassy weed that plagues lawns all over the world, and Kansas City is no exception! This weed often gets misidentified as a healthy grass type, especially when it is in the early stages of its development. However, crabgrass will quickly deplete the soil of its natural resources and create an uneven and unsightly lawn. To make sure this doesn't happen to you, the Heartland team has put together this guide to crabgrass to teach you how to properly identify and prevent this ugly lawn weed.

What Does Crabgrass Look Like?

crabgrass bunch growth

The appearance of crabgrass is similar to whatever turfgrass you may have in your lawn. Thankfully, there are some subtle differences you can look for to help determine whether you are seeing crabgrass or turfgrass. One of the first things you will notice in a crabgrass invasion is the unique (and unattractive) clump-type growth pattern of crabgrass. This differs from the attractive, uniform appearance created by a healthy turf type. Upon closer inspection, crabgrass can also be identified by its slightly rolled stems that will typically appear white or faint pink at the base. It is often said that viewing crabgrass from above can reveal a crab leg-like appearance due to the weed's long, sprawling stems, especially when a pink hue is present.

Leaf blades of crabgrass, unlike most grass in lawns, could be slightly hairy and grow in opposite pairs up the stem. The most obvious difference is the bright green color (or dark green, depending on the species) you can usually expect to see, which differs from the color of grass in many lawns. If you see this atypical color and low, clumping growth in your lawn, crabgrass has likely found a home in your yard!

Look For These In Your Lawn:

  • Leaves from faint yellow to dark green
  • Flat and wide leaves
  • Occasional hairs on the sheaths
  • Coarse texture on leaf blades
  • Long, rolled stems
  • Low, prostrate growth
  • Finger-like, spiky seed heads
  • Shallow, fibrous roots (when removed)

Types Of Crabgrass

The descriptive factors mentioned above will help you identify the different types of crabgrass, but understanding more about the most common types to invade Kansas City lawns will go a long way in making a positive identification. Without proper knowledge of the two most common types of crabgrass, many people often mistake the weed for a healthier type of vegetation. Due to the invasive and prolific nature of crabgrass, making this mistake could quickly spell disaster for your grass and gardens. So, let's learn just a little more about smooth crabgrass and hairy crabgrass!

Smooth/Small Crabgrass

crabgrass roots

Also known as small crabgrass, this species is the most common variety of crabgrass in the United States. As you can probably guess from the "small" nickname, this species develops smaller leaves and grows lower to the ground than large crabgrass. Typically, smooth/small crabgrass does not exceed 2-2.5 feet in length (in ideal conditions), and the individual blades of grass are slightly less wide than those of hairy crabgrass. This weed is also referred to as smooth crabgrass because the sheath and leaves of this species do not have any hairs, unlike its aforementioned counterpart. You may also be able to identify small crabgrass by a faintly red or pink stem that is observable when viewed from above.

Hairy/Large Crabgrass

identifying hairy crabgrass

Hairy crabgrass is often referred to as large crabgrass, and both nicknames are clues on how to differentiate this species from smooth crabgrass. This variety is more common in the northern United States, while smooth crabgrass is more prevalent in the South. You will find both types of crabgrass here in the great state of Kansas, but our dry weather and soil conditions are more likely to breed hairy crabgrass. Its leaves tend to grow longer than those of small crabgrass, reaching maximum lengths of up to 3.5 feet. One of the quickest ways to identify hairy crabgrass is by finding small hairs growing on the sheaths of leaf blades, which are not present on smooth crabgrass. The leaves of large crabgrass are also typically wider than the leaves of small crabgrass, but height and hair are always your most obvious signs. Usually, but not always, hairy crabgrass stems will have a more white color near the base.

When & Where Does Crabgrass Grow?

crabgrass emerging

As a summer annual, crabgrass starts its life cycle in mid to late spring, or whenever temperatures are ideal for seeds to germinate. Temperatures need to reach up to 55 degrees Fahrenheit before seeds can begin germination, so the time of year when you can expect to see crabgrass is really a matter of climate zone and weather patterns. In Kansas, you can expect to see crabgrass in late April, as this weed is notoriously one of the first lawn weeds to appear in a growing season. In colder northern states, however, it is not uncommon for these weeds to begin their life cycle as late as June or July.

As annuals, crabgrass weeds live out their entire life cycle in one year. After emerging in warmer temperatures, these weeds will use their shallow and fibrous roots to absorb nutrients and moisture in the soil before your lawn or other healthy plants even have a chance to absorb the resources. As it grows and matures, crabgrass will develop a seed head and disperse its seeds in fall, many of which will find their way into other areas of your yard or even areas that are many miles away. These seeds will lie dormant as they overwinter, and the cycle starts over again with all new crabgrass plants in the following spring. Lawns that have a lot of open sunlight and well-draining soil are the perfect landing spot for crabgrass seeds.

How Does Crabgrass Spread?

crabgrass seedhead (2)

Summer annual lawn weeds spread primarily by seed dispersal because they do not have as much time to develop the complex root systems of perennial weeds. Unfortunately, a single crabgrass plant can produce 150,000 seeds in just one season, which is why crabgrass is so prevalent and difficult to manage once established. Seeds can be dispersed by the slightest contact, including a strong gust of wind, or they will simply fall to the ground and into the soil as the existing weed dies. Crabgrass seeds can remain dormant in the soil for several years before germinating. This means that even if you're able to get rid of all the crabgrass plants in your lawn today, there's a good chance that the weed will come back next year or even several years from now.

How To Prevent & Treat Crabgrass

The importance of mowing your grass to the proper height

Homeowners and lawn care enthusiasts in Kansas City should expect to see crabgrass at some point in the year, no matter how much maintenance and care they put into their lawns. When this happens, there are a few things you can do to mitigate the damage, but there are also steps you can take throughout the year to prevent crabgrass from establishing a presence. We highly encourage you to call Heartland Turf & Landscape for the best weed control in Kansas City. Our technicians know exactly how to treat your lawn and yard for crabgrass without damaging any of your precious grass and other plants. Give us a call today at (913) 238-9278, and keep the following tips in mind for the best crabgrass control practices!

  • Pull Immature Crabgrass: Removing crabgrass before it develops a seed head is the best way to prevent an infestation in the following year.
  • Dig Out Roots: Established crabgrass will have roots that are slightly stronger, so digging down and around the fibrous roots is best.
  • Apply Pre-Emergent: Early spring is the best time to apply a pre-emergent weed killer, which prevents seedlings from being able to emerge.
  • Overseed In Fall & Spring: Keeping your lawn lush and thick is key to choking out crabgrass, and seeding is effective when crabgrass seeds are germinating.
  • Mow High: Prostrate growth and high sunlight requirements cause crabgrass to struggle in taller lawns, which also means deeper and healthier grass roots.
  • Use Grassy Weed Killers: If all else fails, small bunches of mature crabgrass can be removed by directly applying grassy weed killers, but professional help is always best due to the non-selective nature of these chemicals. Call Heartland today to save your turf & landscape!