Remember that old saying “April showers bring May Flowers”? This gives us hope that after the rains, spring will burst with Tulips, Azaleas, Cherry Blossoms, Dogwood Trees, Flowering Crabapple Trees, and the like. But there is something else that catches our attention during spring, along with that new life filled with color and aroma comes to the “other” perennials, the dreaded and sometimes belligerent weeds! The best way to combat the war on weeds, is with pre-emergent herbicide, but what do you do if you missed those applications, or we didn’t even realize you had any until the conditions were just right; weeds can remain dormant for months, and even years, until the moisture of the rain and the warm weather create the ideal condition them (dandelions, crabgrass, nimbleweed, red thread, etc…).
Perennial & Annual Grassy Weeds
Northern & Central Illinois perennial grassy weeds are considered to be the most difficult weed problems to deal with in lawns. Control options are limited because the weed species are very similar to the lawn species. In fact, many perennial grassy weeds are not considered weeds but are considered desirable grasses when growing by themselves under a different set of conditions. For example, several common perennial grasses, when growing in Kentucky bluegrass lawns, are considered weeds because they differ greatly in leaf width, color, or growth habit. Tall fescue is more coarse and grows in distinctive clumps when it occurs with Kentucky bluegrass. Creeping bentgrass, a very desirable turf species for golf courses, become a weed in bluegrass lawns because it appears as patches of finer grass, usually lighter in color. Zoysiagrass, a warm-season turf species, appears as patches of thick grass, dormant (straw-colored) for much of spring and fall in Kentucky bluegrass or other cool-season grass lawns. One way to distinguish perennial grasses from annuals is the time of the year established plants are present. Perennials (other than nimblewill and zoysiagrass) will appear as established green grasses early in spring; whereas most annual grasses like crabgrass don’t appear until late spring or early summer. Likewise, most annuals die off quickly in fall, but perennials do not.
So, the question is, WHAT DO YOU DO WITH THESE GRASSY WEEDS???
Removing creeping grasses like Nimblewill & Creeping Bentgrass by hand is one control option. It’s important to get all of the plants, as many have underground or above-ground stems (rhizomes or stolons). These stems enable these species to spread quite readily, so if broken or cut, they regrow. Once you have removed the entire plant, you can seed the area & keep watered to grow the desired turf. We do have control options for both Nimblewill & Creeping Bentgrass can be viable option for smaller infestations. For widespread infestation, renovation is the preferred route, when in doubt, a Taylor’s Way Lawn Care Expert will be happy to assess your options.
Selective chemical control is not an option with most perennial grassy weed species. Unlike selective herbicides used on annual grasses (i.e. crabgrass), nonselective herbicides used to control perennial weed grasses may also damage the lawn species. For this reason, spraying over the lawn is not suggested unless the problem is severe enough that all grasses need to be killed and the lawn reestablished. Using a nonselective herbicide, such as glyphosate, patches of the undesirable species can be spot treated. After weeds and portions of lawn die, reseed with desirable grass species.
Around this time as weeds start to pop, we get a lot of calls that people feel like they are seeing crabgrass, often times, this can be confused with another grassy weed, like tall fescue. Crabgrass typically begins germinating and popping up towards the late weeks in May and into June, all temperature dependent. Preemergence herbicides prevent annual grassy weeds such as crabgrass from emerging. The timing of applying herbicides is important, as the control product should be applied before the crabgrass emerges from the soil. Crabgrass will germinate when soil temperatures are greater than 55 to 60F° for 7-10 consecutive days, and continues until soils reach 95F°. Other annual grasses germinate as soils get warmer than 60 degrees. All existing clients who are on our fertilizer & preemergence herbicides have received these applications and we are now beginning broadleaf weed control applications. Our standard lawn programs include 2 rounds of broadleaf weed control after the preemergence; one end of April throughout May and into the first weeks of June, the second beginning in August through the end of October.
Another problematic summer, grassy weed is Nutsedge. It often emerges in early to late summer, earlier in landscape beds. It is a yellow-green color, with a rapid growth rate, outpacing the growth of your turfgrass. Nutsedge is not a grass, but rather a sedge, requiring specialized selective control in the lawn. It spreads by seed and also vegetatively by nutlets and rhizomes underground. Seeds & nutlets can remain dormant in the soil for many years, given the right conditions; heat and lots of rainfall, can emerge and become problematic for some years and can be aggressive in colonizing wet and compacted areas. Give our lawn experts a call if you think you may have Nutsedge so they can assess your situation and recommend a treatment plan.
Some things that tend to encourage grassy weeds are:
Despite what you might think, weeds don’t just pop up on your lawn at random. Some weeds prefer certain types of soil, and you can usually interpret the appearance of a weed in your lawn as a sign of some problem or weakness in your lawn. Factors such as compacted soil, too much or too little fertility, soil that remains wet for long periods of time or has water drainage problems, dry soil, shady areas in your lawn, and problematic pH can all give weeds an inroad into your lawn. Addressing these problems in your lawn with a dependable, comprehensive lawn care program can not only improve the overall health of your yard but will also prevent weeds from cropping up and competing with your grass plants for nutrients and water.
Close-mowed lawns tend to open up, allowing weeds like crabgrass to invade (keep mowing height around 3″). Light, frequent watering also favors crabgrass. Crabgrass often invades areas seeded in late spring because of bare soil, frequent watering, and the onset of hot weather – all ideal for its growth.
Broadleaf Weed Problems in Northern & Central Illinois
Identifying the weed and trying to determine why it has invaded is the first step in managing broadleaf weeds in lawns. Weeds can be indicators of underlying problems. For example, ground ivy invades lawns in the shade, while knotweed may indicate soil compaction. Assorted weeds may indicate poor lawn grass conditions and/or poor management.
After identifying the weeds present, step two for controlling broadleaf weeds should be to review lawn care practices and make adjustments as needed to assure a good stand of grass. Sound lawn care practices should promote a healthy, vigorous turf able to prevent and compete with weed invasions. These practices include proper selection and establishment, fertilization, watering, mowing, and related practices. Alter the environment that may be favoring weeds, such as reducing shade or improving poor soil conditions. A way to reduce shaded areas in lawns would be to have an ISA Certified Arborist assess any trees in the lawn that could use thinning or trimming to allow more sunlight through to the grass.
Violets are broadleaf weeds that require specialized control. They require two consecutive applications in the fall, for best control.
What to expect with broadleaf weed control applications: when we come out to spray for broadleaf weed control, uptake can happen within hours, but full control might not be visible for 7-10 days. Do not mow the lawn for 24 hours after application. Applications are rain-fast within two hours of application and can withstand up to a half-inch of rain within that window. If you are not seeing control after 7-10 days, please call our office so that we can stop back out and re-apply at no cost to you.
Weed management can be a pretty daunting and tedious task for the homeowner to take on. If you need help, call Taylor’s Way Lawn Experts to assist you with either one-time maintenance or to set up a maintenance schedule to give you extra reinforcement at 815-875-8231.