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Crabgrass - July Weed of the Month

Crabgrass - July Weed of the Month

July's featured weed is Digitaria aka crabgrass.

The most common crabgrass in the Southeast is large crabgrass, Digitaria sanguinalis.

Everybody knows the name, but doesn't know what to do about it. Walk with us through the weed patch to discuss crabgrass and what to do about this common weed.

Viewing Tip: Increase the volume and the playback speed according to your preferences. Volume control is the speaker icon on the lower left; playback speed is the gear button on the lower right.

Large Crabgrass ID Features:

  • Family: Crabgrass is in the Poaceae family, commonly called the grass family.
  • Habit: It starts from a central crown, then sprawls in a crab-like fashion. Hence, crabgrass.
  • Flowers: Grassy, green-colored flower and seed heads with 7 to 10 racemes.
  • Leaves: Large blades that give it a coarse texture and are larger than any lawn grass. 
  • Stems: Large crabgrass has burgundy (reddish brown) stems that root at the nodes. This color and the nodal rooting are important identification features. The stems of "large crabgrass" are slightly hairy, though the stems of "hairy crabgrass" are remarkably more hairy and once you see hairy crabgrass, you'll easily tell the difference between the two.

crabgrass habit2

Sprawling large crabgrass that found purchase in a bare spot without mulch.

crabgrass habit3

Sprawling and more crab-like habit of large crabgrass that found a place to germinate in fire pit rocks, with a visible center crown.

crabgrass center crown

The center crown showing hairy stems and the reddish brown stems.

crabgrass stem rooting at nodes-2

Note the reddish brown stems, the hair on the leaves, and the roots forming at the leaf nodes.

crabgrass flower raceme

Flower head of large crabgrass showing 8 racemes.

There are many different types of crabgrasses in the Southeast. If you're a beginner at learning weeds, just getting it to the level of crabgrass is a great start. Besides large crabgrass, you're most likely to find smooth crabgrass. It is less hairy, has shorter leaves, and grows in a tighter clump.

Learn more about large crabgrass from these websites:

There are two look-alikes, dallisgrass and goosegrass, that we'll explore in a later episode, but I want you to be aware of them if you're in doubt if you have large crabgrass or not.

 

Eat it or Treat it

Crabgrasses are in the Poaceae family and are technically edible. It takes a lot of work to harvest their seeds by hand, though this is a useful foraging tip if you're entering one of those survivalist TV shows.

Prevention:

  • #1 Best tip for Crabgrass Control: In February spread pre-emergent herbicide to prevent germination of summer weeds, such as crabgrass. Crabgrass germinates early in winter so if you have a crabgrass infestation, we recommend you don't miss applying pre-emergent in early February. If you subscribe to our email we'll send you an email reminder or sign up for Lawn Coach and we'll send the pre-emergent to you at the right time.
  • Prevent crabgrass in beds with thick layers of mulch and by cultivating a thick, healthy lawn.

link to read more about Super-Sod's lawn coach fertilizer subscription

 

Manual:

  • Hand pull - It can become a big plant, but it's easy to pull up by yanking it by the crown. I use a CobraHead long handle weeder that saves my back from stooping. With this tool I keep standing to snag the crown, pull it out, then with a flick of the tool toss it aside. Very satisfying. 
  • Mow to keep larger plants from going to seed.
  • Time/Patience: Crabgrasses are annuals that will be killed by frost in autumn. Sometimes time/patience feels like hard manual labor, doesn't it?

Chemical:

  • Use a post-emergent herbicide for grassy weeds, such as Quincept. However, don't use Quincept on Centipede laws as Centipede is very sensitive to chemicals and it could possibly be destroyed. Quincept is safe for all other lawns. Always apply according to directions on the label and use a surfactant to help it stick.

    Since recording the video, we have learned that Tenacity, previously only available to licensed commercial applicators, is now available to homeowners for crabgrass control on Centipede lawns. Please test it on a section of your Centipede lawn before applying it to the entire lawn and carefully follow the directions on the label.

    Order Quincept for shipment or schedule it for pick up at your local Super-Sod.
    Order Post-Emergent Herbicide Here

July weed of the month crabgrass-1


 

Topics: Weed Control, weed management, weed prevention, weeds, Weed of the Month

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