“What is this, and how do I get rid of it?”
We often hear this in our stores during the summer. Managing lawn weeds can be frustrating, even for seasoned homeowners. Better control can be achieved through preventing the germination and spread of weeds, rather than trying to get rid of them later in the season. A healthy lawn is the best defense against weeds. When weeds are controlled and the lawn is healthy enough to fill in, chemical treatment becomes less necessary. We’ll focus on a few common weeds around the Lincoln area. If you run into any that aren’t on this list, pull up a sample or take some photos and stop into one of our store locations. We’re happy to advise you on the best course of action to take.
The key to controlling weeds lies in their leaf structure. There are two major types of weeds: broadleaf and grassy. Selective herbicides target plants based on their leaf structure, so it’s important to know what kind of weed you have in order to properly target it.
Applying preemergents early in the spring can create a barrier against seed germination of grassy weeds. Seeds will germinate when the soil reaches a certain temperature, so application of the preemergent should be as close to that time as possible. Watch our Facebook page, we’ll keep you updated on soil temperatures as the weather warms in the spring. If you are seeding a new lawn or overseeding an existing lawn, make sure you select preemergents that are labelled for new seed. Otherwise they will also prevent the germination of grass seed. Preemergents are usually granular and need to be watered in to activate the chemical.
Postemergent herbicides are absorbed into the leaf of the growing plant and move through it to kill the roots. Some of these weeds are annual, which means they grow and reproduce in one growing season. These weeds need to be controlled before they go to seed in the late summer or fall. Others are perennial, which means they can overwinter and live year after year. These can be hard to kill and may need several applications of herbicide before they are under control. If you choose to dig them up, make sure you get the whole plant, any small piece of root can sprout a new plant. Make sure to apply chemicals when it’s cool, treatments during the hot summer could damage your lawn. Postemergents come in granular and liquid form. Apply granular herbicides early in the morning when the grass is dewy or lightly sprinkle your lawn with water before use to help the chemical stick to the leaf surface. If you have a newly seeded lawn, it will need to be mowed twice to harden it off before herbicides are used.
We like liquid Fertilome Weed Free Zone to take care of broadleaf weeds in the lawn. The second application of a granular four-step fertilizer program usually has a postemergent herbicide that will also help control these weeds.
Dandelions are biennials. They spend their first year sending a deep taproot into the soil and forming a rosette. The second year they bloom and spread their seeds, often with the help of small children. Chemical treatment of dandelions is most effective in the fall when the plant is sending energy down to the taproot. If you catch it early in the spring when the plant is still small, you may have good luck controlling it.
Perennial white clover can take years to control. They have extensive root systems, so digging these can cause more reproduction rather than control. Repeat applications of herbicides at regular intervals will be necessary to stay on top of this weed. However, white clover is becoming an alternative to traditional lawns for some homeowners because of its low water needs, ability to fix nitrogen into the soil, and its value as a source of nectar for pollinators.
Ground Ivy/Creeping Charlie
Ground ivy generally begins growing in shady spots. Each ground ivy plant will send out shoots in several directions, forming a mat. Pulling up these mats by hand can be a quick fix, but you need to be diligent to gain control this way. Use an herbicide at a regular interval to control this perennial. Treat in the spring when the plant is in bloom or in the fall before it goes dormant for the season.
Henbit has square stems, usually about 6 inches tall, and the leaves have a minty smell. In the spring, these plants can be raked up and because they’re annual, will not grow back. If you use an herbicide, application should be before they bloom in mid-April. After that, the herbicide will kill existing plants but not prevent future seeds from germinating. A thick layer of mulch in the fall can prevent seed germination in the spring.
This is one of the toughest annual weeds to control. Crabgrass is a clumpy grass that is slightly hairy with a large, airy flower. It germinates when the ground temperature reaches 56 degrees, so it’s best to apply a Crabgrass Preventer before that. Don’t apply it too early, most preventers only last 60 days. Applying too early can result in summer germination. If you need a postemergent, we’ve had good luck with liquid Bonide Weed Beater Plus Crabgrass and Broadleaf Weed Killer.
Goosegrass is an annual similar to crabgrass, but the leaves are smooth rather than hairy, and the flower is thicker. It emerges later in the spring than crabgrass, and can be tough to control. It’s best to use a preemergent that is labelled for goosegrass (many crabgrass preemergents are!) to prevent the seeds from germinating. It shows up in poor soils with sparse turfgrass, so a healthy lawn will help control this weed. Both crabgrass and goosegrass are easier to control when the plants are young. Tenacity is one of the only selective chemicals that will treat goosegrass after it emerges, but be careful to only use it during cool weather or it can cause damage to your turfgrass. If you get sticker shock from Tenacity, RoundUp or Burn Out will work, but these are both nonselective so they will kill your turfgrass, too, so apply with care.
Windmill grass has become more common in Nebraska after the droughts thinned out lawns. It is a short bunchgrass with stems that mostly lay along the ground, except for those that produce a seed head that can be up to 16 inches tall. It is an indicator of poor soils, commonly found in hot areas like next to sidewalks. It spreads by seed and can multiply from the roots, so it can take years to control. Tenacity is one of the only selective chemicals that will control this.
Nimblewill’s stems lay horizontally along the surface of the ground, with short, smooth leaves. This warm season perennial emerges late in the spring when the ground temperature reaches about 70 degrees, long after the lawn has begun growing. It is especially noticeable in the fall when it browns much earlier than the rest of the turf. It produces horizontally-growing stolons that will root anywhere their nodes come into contact with the ground. Tenacity or a nonselective herbicide will help control nimblewill.
Quackgrass forms and upright clump like crabgrass, but the flower produces seeds on one straight spike on top of the stem. A high-nitrogen fertilizer and frequent mowing can take care of quackgrass, causing it to be out-competed by your lawn. Its extensive system of rhizomes and deep root system make it difficult to control this weed by pulling. There is not a selective herbicide commercially available for quackgrass. A non-selective herbicide like RoundUp can be used, but be careful, this will also kill your lawn grass. It will need to be used at regular intervals to gain control.
Nutsedge can be identified by the triangular shape of its stem (sedges have edges!) and the spiky yellow or brown flower it produces around August. It produces tubers underground, which can remain dormant in the soil for years until conditions are favorable for them to sprout. Nutsedge usually emerges late in the spring, in May or June. Treatment can begin as soon as the plant is growing, and ideally finish before summer solstice. Use a nutsedge specific chemical like Ortho Nutsedge Killer.
Notes on using chemicals
The applicator is legally obligated to read all labels before using any chemical. Herbicides are prone to drifting, especially when temperatures are above 85 degrees or when winds are above ten miles per hour. When targeting broadleaf weeds, for example, the chemical can drift and damage a nearby tree or ornamental bed.
Some areas of the country are experiencing chemical resistance in crabgrass and other species. Be careful to mix the proper amount of chemical according to the label.
If you’re unsure about how to responsibly use one of our chemicals, please talk to one of our sales associates, we’re here to help!