INVASIVE WEEDS OF SOUTHERN ILLINOIS: Part One: How to Manage Them

by Lauren Cook on .

  Along with the warm weather, comes the need fight back against those pesky weeds that keep trying to take over our lawns and flower beds. The Webster Dictionary defiines a weed as “a plant that is not valued where it is growing and is usually of vigorous growth; especially one that tends to overgrow or choke out more desirable plants.” If not routinely maintained, invasive plants can turn even the most extravagant or well-designed landscape into a complete eye sore.

We all love the long growing seasons of Southern Illinois, but so do some of our fastest growing weeds. What can be done to make sure you don't spend your summer being a slave to your yard? Listed below are some of the toughest weeds in Southern Illinois, along with the most effective ways to manage them. These are weeds that no mulch, no weed barrier nor chemical spray can kill:

Clover -

Plant Characteristics:

    •  - Green to light green, three-lobed leaves

    •  - Grows in clumps in lawns and flower beds

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How to Manage:

Herbicide will usually work to kill clover, but it usually will take atleast two consecutive sprays. It always helps to spray on a hot, sunny days. Clover is hard to pull by hand, but could probably be dug out with a trowel or shovel if care was taken to remove all of the roots.

Bermudagrass

 Plant Characteristics:

    •  - Spreading, carpet-like grass-like

    •  - Dormant from November to May, invasive  growth during warm months

    •  - Bright green grass-like leaves, 1-2” tall

       

 

How to Manage:

Once you have Bermudagrass, you will have maintenance issues keeping it out of your flower beds and lawn. Bermudagrass will have to be continuously sprayed with herbicides to weaken the plant to the point at which it can be maintained. Each time you spray, the herbicide will kill the top part of the bermudagrass plant, turning it brown. Approximately two weeks later, the bermudagrass will begin to leaf out and you will spray again and so on. Each time you spray you weaken the bermudagrass. However, even the smallest piece of bermudagrass left living can rapidly turn into another infestation.

 Crabgrass -

Plant Characteristics:

    •  - Dark green, grassy leaves, 3-5” long

    •  - Growth is flat and spreading

    •  - Annual warm season grass

    •  - Grows April through October in Southern Illinois

How to Manage:

Crabgrass can be prevented by applying a granular pre-emergent herbicide or crabgrass preventer to lawn and garden areas in March. Spread according to directions before a spring rain.

Yellow Nut Sedge -

 Plant Characteristics:

      •  - Bright green/chartreuse grass-like leaves

      •  - Approximately 12” tall

      •  - Rapid spreader during the warmer months

      •  - Yellow, sphere-shaped seedheads

 

How to Manage:

Like Bermudagrass, it is difficult to kill yellow nut sedge, the best strategy is to try to contain it. Because yellow nutsedge is a sedge and not a grass or a broadleaf weed, most herbicides will not work to kill nut sedge. There are yellow nutsedge-specific herbicides available in stores, such as Sedgehammer. These products will weaken nutsedge and help keep it from spreading. Along with regular spraying, make sure the plant does not go to seed. Refrain from pulling the plant. It is very difficult to remove the entire root from the soil and anything left will multiply into more plnts.

Wild Garlic -

 

Plant Characteristics:

      •  - Thin, grassy-looking leaves, light green

      •  - Onion odor when trimmed or mowed

      •  - Tiny clusters of hanging white flowers

    •  - Seems to pop up everywhere in spring and fall

       

How to Manage:

Wild garlic is hard to remove by hand. It is difficult to remove the entire root system. Even herbicides can be difficult to use because the liquid spray easily runs off the thick, glossy leaves of wild garlic. To increase the effectiveness of the herbicide, weedeat or mow the wild garlic prior to spraying to scar the leaf tissue and make it more susceptible to the herbicide.

 

For less invasive weeds, apply a pre-emergent herbicide in April and again in August to flower beds and lawn areas. Maintain a layer of mulch between two and three inches thick and keep landscaped areas free of plant debris. Stay Tuned for INVASIVE WEEDS OF SOUTHERN ILLINOIS Part Two: Why They're Actually a Good Thing.