Crabgrass is one of the most resilient, hardy weeds that, if not handled properly, can thrive well on lawns, garden beds, and even concrete. On a general scale, there are nearly 35 types of crabgrass.
Learning about the most common crabgrass varieties and ways to identify them can help you get rid of these annoying pests in your garden.
What is Crabgrass?
Crabgrass is a warm-season lawn weed that initially comes from the tropics. It is also known by the name Digitaria – a species that includes both annual and perennial types of grass.
Digitaria, in Latin, means ‘fingers.’ So, that’s one way for crabgrass identifying; it looks like fingers creeping all over the lawn.
Typically, you can find grassy weed almost anywhere in the world. Its ideal living habitats are lawns that are thin and not being treated properly (not enough watering, trimming, fertilizing, etc.).
This lawn pest expands in circles of up to 12 inches in diameter. In autumn, the weed dies out, leaving circular patches behind, which will later drop thousands of seeds into nearby areas for the following growing season.
Learn why crabgrass will grow in a lawn and how to prevent crabgrass from germinating in a lawn without using lawn chemicals:
Most Common Types of Crabgrass
Short, or Smooth Crabgrass
Did you know that 90% of all the crabgrass in Michigan gardens is smooth crabgrass? Short crabgrass, or smooth crabgrass, is originally from Europe and Asia. However, it is mainly found in North America. This type of weed only grows to 6 inches high with smooth and wide stems.
At maturity, the leaves of short crabgrass can grow as much as 5 inches in length, depending on several growth factors like soil, moisture, temperatures, etc.
The leaves are curled in the bud with no auricles. Instead, you’ll often see its compressed sheaths with a tinge of purple, whereas the stems sometimes appear in red.
The grass germinates best in spring when the soil temperatures get around 55℉. Summer months, especially mid-summer to late summer, are when they’re thriving.
Long, Hairy Crabgrass
Long, hairy crabgrass is native to Africa, Asia, and Europe. It has a variety of names, including large crabgrass or Digitaria sanguinalis.
You can tell long crabgrass from smooth crabgrass thanks to the hairs on its stems. Also, its leaves are longer and much wider.
Hairy crabgrass grows well in rich clay or sandy soil, but you’ll likely encounter it almost everywhere: gardens, sidewalks, cracks, and even landfills.
On a broad scale, these finger-like grasses can grow up to 1-3 feet tall. However, if not mowed, it can easily reach 2 feet in height within days.
The flowers are organized in finger-like ranges of 2 to 15 spike-like clumps, creating 1 to 3 whorls. The leaves can reach 2 to 10” long and about ⅔” wide.
Native to Asia and Australia, Asian Crabgrass, also known as Digitaria bicornis, is unique from its mentioned counterparts. Unlike the name suggested, the weed is often found in the Southeastern United States and South America.
While some homeowners see Asian crabgrass the same as any other plant in the garden, others consider it nothing else but a lawn pest. But, of course, there are still people that find value in this weed and grow it in their gardens, which is just exceptional.
Asian crabgrass isn’t as picky as its other counterparts; it can sprout and grow well in different climatic conditions, from tropical/subtropical to temperate climates.
Southern crabgrass is originally from the Americas, Asia, and Africa. It is pretty similar to smooth and large crabgrasses in terms of growth pattern. The most significant difference to distinguish it from others is its prominent midvein.
Its leaf blades either have no hairs or very few hairs going all the way down to the base of the blade. However, like the large crabgrass, its leaf sheath has long hairs.
Southern crabgrass’s scientific name is Digitaria ciliaris. It is said to come from Asia, even though you can find it all over the tropical belt and even temperate regions.
Less Common Types of Crabgrass
Blanket crabgrass has the scientific name Digitaria serotina. This short and hairy plant is from North America; it is commonly known as rabbit crabgrass or dwarf crabgrass.
Blanket crabgrass is a short-term perennial plant that flourishes mainly in warm climates but can be found almost globally. The plant primarily propagates through seed, though it can spread quickly by self-grow roots at respective nodes.
So, before you know it, a blanket crabgrass outbreak can be your worst nightmare ever. When the weed goes to seed, this means it is eligible to reproduce itself and drop even more seeds.
The thing is, regular weed control or herbicide will not work on killing these seeds. So the only thing you can do to prevent the next outbreak is to keep on mowing as much as you can.
At maturity, the weed often remains on the ground with its stems running along with the soil. Its flowers, on the other hand, characteristically rise off the ground erect. The flower stems are quite short, with hairy leaf sheath and blades.
Similar to this plant, there’s Indian crabgrass, which has leaves smaller than an inch. Or Texas crabgrass, which thrives well in hot weather and dry or rocky soil.
Other Forms of Crabgrass
Different types of crabgrass may not be in your area, but these crabgrass varieties do exist. Other species are often named based on where they come from or where they are commonly found.
For example, the Carolina crabgrass. Where do you think the plant comes from? That’s right – Carolina! Or, to be more specific, North Carolina.
Likewise, the Madagascar crabgrass is found in Madagascar, and Queensland blue couch mainly grows in Queensland.
Apart from naming based on the origin, most of these varieties are given quite ‘vivid’ names that live up to their characteristics. For instance, cotton panic grass, naked crabgrass, or comb finger grass.
Consult the area around you, and you’ll be surprised to find more than one type of crabgrass!
Tips on how to remove the crabgrass
As mentioned, once there is a crabgrass outbreak, there’s nothing you can do to prevent it. However, there are several methods to discourage the growth of this lawn pest.
Start by mowing your grass to the lowest setting, raking out all the vegetation, and dispensing new grass seed. It is important to keep mowing every 3-4 days and treat it with a post-emergent herbicide.
Remove any weed in the future by hand and apply a pre-emergent herbicide for the following spring – when this lawn grass germinates.
Frequently Ask Questions
What does Blanket crabgrass look like?
They come in all shapes and sizes, but the most noticeable thing is that they look like dark green or light green grass growing up to 6 inches high.
How do you identify crabgrass?
Crabgrass are the most common weeds in North America. They have wide leaves that are round with fine, shallow serrations around the edges. The roots of crabgrass creep deep into the soil to form a mat or tangle.
There you have it – the types of crabgrass. Unfortunately, this invasive weed is a common occurrence, so don’t be too surprised to encounter it in your healthy lawn.
The real question is, is crabgrass a weed? While some people grow these finger-like grass in their garden for specific nutritional values, others consider most of them as weeds detrimental to the lawns and should be gotten rid of.