Grassy Weed Seed Head Identification

ILGM

Buy Cannabis Seeds Online

Learn how to identify different types of grassy weeds and keep your lawn in great shape year round with TruGreen®. Annual grassy weeds are some of the more frustrating lawn weeds homeowners will encounter. Weeds will not only hurt the look of your lawn, they will also rob your turfgrass of sunlight, water and other nutrients. Identifying weeds can…

Grassy Weeds

To the untrained eye, distinguishing turf grass from grassy weeds is tough because the two can look identical. But with practice and persistence, you can learn to identify lawn weeds—and even the difference between grass and sedge—by inspecting the primary vegetative characteristics of your lawn.

Here are some of the features our TruGreen® experts use to weed out the bad grasses.

  • Crown. The white, thick part of the grass plant at soil level where the shoot meets the roots. It’s central to lawn health—if the crown dies, the grass plant dies.
  • Sheath. The lower (basal) portion of the grass leaf between the crown and the blade that encloses and protects young shoots of grass. Sheath margins may be split, split with overlapping margins or be closed.
  • Collar. The backside of a leaf where the blade and sheath join. Collars may be divided by a line that runs up the center (mid-rib) or be continuous. Collar shapes vary from narrow to broad and can have slanted or straight borders.
  • Blade. The section of the leaf above the collar. Characteristics to look for include the type of tip, roughness or smoothness, and mid-rib.
  • Vernation. The leaf arrangement of the youngest leaf (called the budleaf) and its surrounding sheath. Look to see if the budleaf is rolled or folded.
  • Ligule. A tip- or cylinder-shaped structure poking out from the top half of a leaf where the blade and the sheath join. Ligules can be membranous, hairy, both or absent altogether, making them useful for spotting grassy weeds in grass.
  • Auricle. A pair of appendages sticking out from the side of the grass leaf where the sheath and blade meet. Auricles can be short and stubby, large and claw-like, have short hairs attached or be absent, also making them useful grass identifiers.
  • Rhizomes. An underground stem that produces a new plant.
  • Stolons. A horizontal, above-ground stem that roots at the nodes (found in the crown) and gives rise to new grass plants.
  • Seed head. The flowering or seeding parts found at the top of the grass plant. Check if seed heads are spike or panicle to help with turf grass identification.

Life Cycle

An essential part of identifying grassy weeds has to do with their life cycles. For example, you may be able to hand-pull a few annual weeds to enjoy a weed-free backyard cookout, but perennial grassy weeds have a deeper root structure that can give rise to new weeds—even if you no longer see the weeds in your lawn. Learn what the different life cycles of lawn weeds mean for your control plan.

Annual weeds. These weeds live for only one season and are typically easy to control because they lack the complex underground structures needed to spread new plant growth through creeping roots. Still, annuals produce tons of seeds that can infest and dominate your yard under the right conditions.

Summer annuals. These grass-like weeds begin to grow (germinate) in the spring, mature in the summer, and then produce seeds and die by the fall or first hard frost—an entire life cycle completed within 12 months.

Winter annuals. These weeds overlap two calendar years but last only 12 months total. They germinate and develop from late summer to early fall, remain semidormant during the winter and then flower in spring. Come late spring or early summer, they mature and die off as the weather warms.

Perennial weeds. Perennial grassy weeds can germinate and spread from seeds, but they also produce a root structure (tubers, bulbs or corms) that can birth new weeds from your lawn’s surface (using stolons) or from underground (using rhizomes).

Biennial weeds. These flowering plants generally live for two years. The first year consists of leaves, stems and root growth, followed by winter dormancy. In the second year, biennials flower and produce seeds, thus completing their life cycles.

Control

Without a professional service, removing grass-like weeds without damaging your lawn is difficult. The biological similarities of turf grass and grassy weeds make both susceptible to control methods. For example, spraying crabgrass killer at the wrong time can kill your grass seeds. Instead, aim to control grassy weeds by keeping your lawn dense and healthy so they don’t stand a chance. If these turf grass imposters have already invaded your lawn, you can try a few other tactics to weed them out.

What’s the Best Weed Control?

The most effective weed control is a flourishing lawn because it’s more competitive and will crowd out grassy weeds. Weed seeds need light to grow, which a dense lawn blocks out. To keep your lawn lush, healthy and competitive, try:

  1. Fertilization. The right type and application method makes all the difference.
  2. Mowing. Mow frequently at the recommended height with sharpened blades, removing only one-third of the leaf blade.
  3. Watering. Water deeper rather than more frequently when rainfall is scarce.
  4. Changing. Factor in climate, sunlight, shade, etc., to pick the right turf grass. [Links to J.5 Turf Grass Selection Module]
Does Pulling Weeds Work?

Hand-pulling grassy weeds can work if there are only a few, especially if they’re annuals. Perennial grassy weeds are harder to control by hand because you don’t always pull up the vegetative structure, which is what sprouts new weeds.

What Type of Crabgrass Killer Won’t Harm My Lawn?

Postemergence herbicides control existing weeds. Unfortunately, because grassy weeds are in the same family as turf grass, these types of herbicides can also harm your lawn. Preemergence herbicides control seeds only—not existing weeds—making them safer for an established lawn (grass seeds are susceptible). They work on most seed-based annuals and perennials.

Because each yard is unique, TruGreen® customizes a grassy weed control program for your lawn. The plan of attack depends on your region, type of turf grass and the specific weeds invading your lawn.

Identify

To the untrained eye, distinguishing turf grass from grassy weeds is tough because the two can look identical. But with practice and persistence, you can learn to identify lawn weeds—and even the difference between grass and sedge—by inspecting the primary vegetative characteristics of your lawn.

Life Cycle

An essential part of identifying grassy weeds has to do with their life cycles. For example, you may be able to hand-pull a few annual weeds to enjoy a weed-free backyard cookout, but perennial grassy weeds have a deeper root structure that can give rise to new weeds—even if you no longer see the weeds in your lawn. Learn what the different life cycles of lawn weeds mean for your control plan.

Control

Without a professional service, removing grass-like weeds without damaging your lawn is difficult. The biological similarities of turf grass and grassy weeds make both susceptible to control methods. For example, spraying crabgrass killer at the wrong time can kill your grass seeds. Instead, aim to control grassy weeds by keeping your lawn dense and healthy so they don’t stand a chance. If these turf grass imposters have already invaded your lawn, you can try a few other tactics to weed them out.

Grow Your Knowledge With Lawn Care 101

Search, learn and discover all things lawn-related with this helpful resource.

  • Home
  • Login/Register
  • Customer Support
  • Find A Branch
  • Privacy Policy
  • Do Not Sell My Personal Information
  • Terms and Conditions
  • TruGreen Careers
  • Contact-Us
  • TruGreen Rewards
  • TruComplete℠ Lawn Plan
  • TruHealth℠ Lawn Plan
  • TruSignature℠ Lawn Plan
  • TruMaintenance℠ Lawn Plan
  • Soil Amendment Services
  • Outdoor Nuisance Pest Control Plan
  • Training And Expertise
  • Why Use A Professional Service
  • Testimonials & Ratings

For New Service: 1-844-567-9909 or get a Call Back For Customer Service: 1-844-768-0421 or Contact Us Online

**Special price of 50% off is for first Lawn application★, Tree & Shrub application✢, and/or Mosquito application★★ only. All other restrictions apply.

★Requires purchase of annual plan. Special price of 50% off is for first application only, for new residential EasyPay or PrePay customers only, and applies to lawns more than 5,000 square feet. For lawns less than 5,000 square feet or for the regular lawn application price for a lawn of any size, please call for estimate. Lawns less than 5,000 square feet may qualify for a first application only price of $29.95. Valid at participating TruGreen locations. Availability of services may vary by geography. Not to be combined with or used in conjunction with any other offer or discount.

◆Guarantee applies to full plan customers only. ✦Purchase of full lawn plan required for Healthy Lawn Analysis, which is performed at the first visit.

✢ Special price is for first tree and shrub application only and for new tree and shrub residential customers only. The special price applies to installed plant material and shrubs and excludes mature, native and specialty trees such as fruit or certain ornamentals. Application includes up to 5 trees, no more than 25 ft. in height. For the regular tree and shrub application price, please call for an estimate. Not to be combined with or used in conjunction with any other offer or discount for the same service. Consumer responsible for all sales tax.

★★ Requires purchase of full mosquito plan. Special price of $39.95 is for first mosquito application only, for new EasyPay or PrePay residential customers only, and applies to properties up to 1 acre. For properties more than 1 acre, please call for estimate. Valid at participating TruGreen locations. Availability of services may vary by geography. Not to be combined with or used in conjunction with any other offer or discount. Additional restrictions may apply. Consumer responsible for all sales tax. ✧ Guarantee applies to full plan customers only.

America’s #1 lawn care company based on U.S. market share of professional lawn care companies. 2018 NorthStar Partners U.S. Share Tracker. PGATOUR.COM, PGA TOUR, TPC, SHOTLINK and the SWINGING GOLFER LOGO are trademarks of PGA TOUR, Inc. BBB accredited since 7/01/2012.

Annual Grassy Weeds
Identification and Control
– Crabgrass and Foxtail Weeds –

Let’s look first at crabgrass. Most grassy weeds are undesirable weedy grasses that germinate and grow in lawns, but can lower turf quality and appearance. These weeds do not have the characteristics or growth habits that produce a quality lawn.

Annual grass-type weeds are those that germinate from seed each year and die at the end of the growing season. Annual weeds are prolific seed producers since seed germination is the method of producing the next year’s generation of plants.

Crabgrass (Late Spring Annual Weed)

  • One of the most common and troubling grassy weeds.
  • Yellow-green to a darker blue-green in color.
  • Can be prostrate or upright growing.
  • Multi-branched stems. Large crabgrass roots at the nodes.
  • One plant can produce over 150,000 seeds.
  • It doesn’t make a good lawn because it doesn’t take off until late spring or early summer and dies with the first heavy frost.
  • Plants start off sparse but increase in number and size by end of the year.
  • Can be difficult to stop once they start growing.
See also  Weed Seeds For Sale Discreet

Weed Identification

The U.S. and Canada have many grassy weeds with crabgrass being one the most problematic. There are two major species of crabgrass: smooth crabgrass (also called small crabgrass) and large crabgrass (also called hairy or common crabgrass). Smooth crabgrass is found mostly in the northern half of the U.S. and large crabgrass is found throughout the U.S. and southern Canada.

All crabgrass varieties are summer annuals that must come back each year by seed. It is a full sun grassy weed and will only tolerate very light, partial shade. It will not grow in shaded areas.

Crabgrass was originally introduced into this country as a possible forage crop. However, it easily escaped cultivation and is now widespread throughout the country. It is one of the most common and problematic weedy grasses in home lawns. It is also found on golf courses, parks, flower and vegetable gardens, athletic fields and any other place that seeds are able to germinate.

Crabgrass is most at home in areas of thin or poor quality turf. The plants grow quickly and can cover an entire yard by the end of summer.

Crabgrass is yellow-green in color with short, wide leaves. While the seedling look similar to other plants, they soon begin to distinguish themselves. In young plants, like the one in the photo to the left, the leaves are twice as long as they are wide. These young plants begin by growing prostrate with three or four stems branching out in a starfish pattern. As the plant matures the stems will curve in an upward direction. Each plant can produce as many as 700 new tillers (new leaf blades). At full maturity, each leaf will grow to be a few inches long. Crabgrass leaves have tiny hairs on both sides of the leaves.

The roots are shallow and fibrous and do not reach the depth of many other grasses. Large (hairy) crabgrass will root at the nodes and can produce long stolons. Smooth crabgrass does not root at the nodes.

The shallow root system works in their favor by absorbing as much water as possible before it reaches the deeper rooted plants. Frequent, shallow watering will cause crabgrass to flourish at the expense of other grasses. Less frequent, deep watering is better for your turfgrass, but will not neccessarily hinder crabgrass growth.

The photo above is of a mature crabgrass plant, while the photo below is of common bermudagrass.

The leaves of bermudagrass are much finer and are darker in color. Crabgrass seed heads are finger-like spikes that resemble common bermudagrass seed heads. However, crabgrass seed heads are somewhat thicker.

There are usually three to seven spikes that can either be folded up like a funnel or spread out in a whorl pattern. Each plant can produce as much as 150,000 seeds a year. Crabgrass germinates from seed each year when soil temperatures reach 55 degrees for five consecutive days. The blooming of forsythia in your area closely coincides with the germination of crabgrass seeds.

Once the seed has germinated, crabgrass becomes difficult to control. Because of the prostrate growth habit, crabgrass can produce seed heads at mowing heights as low as ½ inch. Mowing your lawn at a height lower than is healthy for your particular grass will only benefit and encourage crabgrass growth.

Cultural Practices that Help Prevent Grassy Weeds

Cultural Practices

Crabgrass, like many there grassy weeds, do not like competition from turfgrass. Crabgrass grows best in poor quality lawns, lawns cut and maintained too short, lawns with disease or insects damage, and in high traffic areas. Lawns with thin or deteriorating grass will give the seed plenty of sun, heat and space for seed germination. A poorly maintained lawn will guarantee that you will have increasing problems with broadleaf and grassy weeds.

If crabgrass is a problem, avoid fertilizing in late spring and summer. Especially avoid applications of high Phosphorus fertilizers. Phosphorus is essential for seedling growth and will only promote crabgrass establishment.

The best method of keeping crabgrass and other grassy weeds out of your lawn is to build a thick, healthy, vigorously growing turf. The first step is to ensure you have the right grass type for your area. Increasing the grass thickness can be accomplished by overseeding, plugging or laying sod, proper fertilization and irrigation. Until the lawn thickens, grassy weeds will continue to be a problem.

It is also important to mow your lawn at the highest recommend level for your specific grass type. This will shade the soil and make germination more difficult. Many cool season turf grasses can be mowed at a height of 3 to 4 inches. Depending on your grass type, see the Cool Season Grasses or the Warm Season Grasses Warm Season Grasses sections of this site for helpful mowing and planting information.

You may find it necessary to use a preemergent herbicide to prevent the seeds grassy weeds and other weeds from germinating.

Herbicide Use

The most effective and proven method of preventing crabgrass from starting is to use a preemergent herbicide. I can’t stress this enough. If you want to prevent crabgrass from ever starting, you have to use a preemergent.

Preemergents are an added ingredient in many spring fertilizer. The bags will be labeled “with Crabgrass Control” or “Crabgrass Preventer”, etc. Make sure you spread the fertilizer at the correct nitrogen (N) level for your grass type. For help developing a sound fertilizer program, read the page on Developing a Fertilizer Program.

A preemergent must be applied before the crabgrass seeds germinate in spring. Again, it MUST be applied before they germinate with only one exception, the use of Dimension preemergent will kill the crabgrass at very early seedling stages. I will describe this in better detail below.

A preemergent (also spelled pre-emergent or pre-emergence) herbicide works by preventing cell division on young plants. A preemergent doesn’t actually prevent the seeds from germinating, as commonly believed. However, once the seeds do germinate, the chemical prevents the cells from dividing and the seed dies. In this way, the seeds are destroyed. An important note: Preemergents will have the same effect on most lawn grass seeds as well. Do not overseed directly before or within a few months after herbicide application or your seed may be ruined.

If you have waited too long and the crabgrass begins growing, preemergents usually have no effect. However, there is one product with the trade name “Dimension” (Chemical name: dithiopyr) that will give some control of seedling plants for a few weeks after emerging from the soil.

The effectiveness of some homeowner type preemergent herbicides is questionable. Some brands don’t perform as well as others. The effectiveness is also related to how it was applied, the amount and frequency of irrigation, amount of rain received, etc.

Keep in mind, if applied too early, the chemical can breakdown too soon allowing mid to late season seeds to germinate. Other chemicals have a short life span and it must be reapplied in mid-summer. Therefore, timing of the application is very important. Outside temperature and soil temperature are important. Remember, crabgrass germinates when soil temperatures reach 55 degrees for five days in the top inch of soil. It is okay to water after the preemergent has been put down, but don’t over water or water too frequently. Frequent, heavy irrigation or heavy rain places maximum stress on these herbicides.

For Established Weeds

Once the weeds are established, they are very difficult to control. Post-emergent herbicides labeled for grassy weeds will need to be used. Most products will require several applications for complete control. Products with MSMA or DSMA will control crabgrass as well as other weedy grasses. The Ortho company makes a product with these active ingredients. Add the correct amount of a “sticker/spreader” to the herbicide mixture for better adherence and absorption into the plant.

There is also the herbicide quinclorac under the trade name “Drive”. This is now available to homeowners and sold by Ortho under the name “Weed-B-Gon MAX Plus Crabgrass Control Ready To Use”. It contains other ingredients to help control broadleaf weeds as well.

Organic Preemergent

The most popular preemergent for crabgrass and other grassy weeds is Corn Gluten Meal. Nick Christians, a turf specialist and university professor in Iowa, holds the patent.

Corn Gluten Meal is sometimes marketed as an organic weed killer for broadleaf and grassy weeds. Although it actually holds little or no weed killing properties it is, however, an effective preemergent. It works by robbing the moisture from developing germinated seeds and seedlings.

One main difference between chemical preemergents and corn gluten meal is the amount applied. Corn gluten meal must be applied between 10 to 30 lbs 1000/sq.ft. Generally, 20 lbs/1000 sq. ft. is the average for most lawns. Use more for severe weed problems. It does not require a license to use.

Timing is important and it must go down near the time that seeds will germinate. After application, irrigate the corn gluten and allow a drying period. This is critical for effectiveness because it must absorb the surface moisture. In wet climates, such as the north western U.S., corn gluten meal may not be as effective. A second application can be made in the fall.

Keep in mind, with corn being used as fuel for vehicles, corn gluten meal is rising in cost. Shop for the best price.

Final Notes

Learn From the Mistakes of Others: Spraying your lawn with a a non-selective herbicide such as Round-up, etc is not an effective crabgrass control. It doesn’t harm the seeds in the soil. Although it will kill all the grass and weeds it touches, the following year you will still have the problem with crabgrass and other broadleaf and grassy weeds that start from seed.

For lawns containing 50% or more weeds with thin or very little grass, a non-selective herbicide can be used if you plan on seeding or sodding soon after. Don’t wait too long to renovate or the weeds will become established and you will have to do it again. Each grass type has a preferred time of year when it should be planted.

Read labels carefully and follow all label instructions. Note that MSMA and DSMA are not recommended for St. Augustinegrass, centipedegrass or carpetgrass.

Yellow and Green Foxtails (Summer Annual Weed)

Foxtails are a summer annual grassy weed. They get their name from the seedhead that resembles a fox’s tail. They can spread quickly in sunny areas but less so in shade. The same preemergents that control crabgrass will also control foxtails.

  • Grassy weeds with characteristic cylindrical seed heads.
  • Yellowish-green to blue-green leaves.
  • Seed heads are 2-3 inch.
  • Reproduces from seed only.
  • Difficult to control once seeds have germinated.
  • You will start to see foxtails as soon as the crabgrass weeds are well-established.
  • The same preemergent that stops crabgrass also stops foxtails.
See also  Marijuana Seeds Dc

Weed Identification

Foxtails are a species of warm season, annual grassy weeds that starts from seed. It grows in full sun, but can tolerate very light, partial shade. It will not grow in shaded areas.

It develops from a fibrous root system and has a prostrate to upright growth habit. With mature plants, it is common to see the stems branching out at the base, remain prostrate for an inch or two and then curve upward at a 30 to 70 degree angle. Each plant can produce multiple stems that can easily grow twice the height of the leaves.

The coarse leaves are a yellowish-green to a darker blue-green color. They can grow to 12 inches long and up to ½ inch wide. The leaves are flat and smooth. The widest part of the blade is at the base. The leaves have small silky hairs on the upper surface near the base.

Foxtails are known for their characteristic seed head that has a foxtail-like appearance. The seed head is at the end of the stalk and usually extends several inches above the leaves. Mature plant can have a dozen or more seed heads and can produce thousands of seeds each year. Seeds germinate when temperatures reach 68 degrees and will continue germinating through most of the summer. Foxtails will die at the first killing frost.

Giant foxtail is another foxtail species that grows 2-5 ft tall, but it cannot take repeated mowing. For this reason, giant foxtail is rarely found in mowed turf. Notice that the seed head of giant foxtail droops, while yellow and green foxtail seed heads do not.

Cultural Practices

The primary way of preventing the establishment and spread of foxtail is to maintain a thick, healthy lawn. Maintaining your lawn at the tallest mowing height recommended for your grass type will help slow seed germination.

Consistent, weekly mowing to remove the seed heads before they mature will also go a long way to deter spread. If you have only a few plants growing in your lawn, try removing them by pulling them up. The plant has a fibrous root system, however, some plants will root at the nodes near the base of the plant.

Herbicide Use

If you have had problems before with foxtails, the best way to stop their development is with a preemergent herbicide. These preemergents are added to spring fertilzers.

The same herbicides labeled for crabgrass will work on many other grassy weeds, including foxtails. Preemergents are added to spring fertilizer and will be labeled “with Crabgrass Control” or “Crabgrass Preventer”, etc. Always check the label before using, however. Once the preemergent had been applied, moisture in the soil will activate it. Fertilizers need to be applied correctly in the amounts needed for your grass type and time of year. Scotts fertilizer brand as well as a few others are good homeowner fertilizers. Bargain brands may not give you the control over grassy weeds that you would like. Since fertilizer applicatons are based on the Nitrogen (N) needs of the grass you will need to know how much to apply. Click on the link for helpful information on Developing a Fertilizer Program.

Most preemergents are designed to last a few months before they begin to lose effectiveness. Not all active ingredients work equally well or have the same duration and homeowner varieties tend to last the least amount of time. This means that your timing will be very important. Important Note: Foxtails will germinate a few weeks to a month later than crabgrass. Something to remember when applying a preemgerent.

Once the seed germinates, the herbicide chemical stops cell division within the seed, so the plant never develops. As a result, the seed dies.

The preemergent herbicide label may list other broadleaf and grassy weeds that it controls. However, most are not very effective with broadleaf weed seeds.

For Established Weeds

Post-emergence herbicides will be needed once the foxtails have become established. The herbicides containing the active ingredients MSMA or MSDA are labeled for many grassy weeds, including foxtails. Read the label carefully and follow all label instructions. MSMA and DSMA are not recommended for use on St. Augustinegrass, centipedegrass or carpetgrass.

There is also the herbicide quinclorac under the trade name “Drive”. This is now available to homeowners and sold by Ortho under the name “Weed-B-Gon MAX Plus Crabgrass/Grassy Weeds Control. It is a “Ready To Use” formulation, meaning it comes already pre-mixed. It contains other ingredients including 2,4-D and Dicamba to help control broadleaf weeds as well.

Nimblewill Grassy Weed
Nimblewill is a grassy weed that resembles bermudagrass. It is most prominent when growing in cool season grasses. Find information on identification, growth habits, and control methods.

Winter Annual Broadleaf Weeds
With each spring comes a surge of winter annual broadleaf weeds. Here you will find valuable information about these difficult weeds including growth habits, photos, and measures that can be taken to control them.

Summer Annual Broadleaf Weeds
Many of the most problematic broadleaf weeds are annuals. Here you will find specific summer annual weed information, with weed names, photos and control methods.

Perennial Broadleaf Weed Identification Page 1
Click here for weed identification and control of common broadleaf perennial lawn weeds. This page has detailed information on Canada Thistle, Mouseear Chickweed, White clover, Dandelion, Field Bindweed, Ground Ivy, and Common Mallow.

Perennial Broadleaf Weed Identification Page 2
This page contains more perennial broadleaf weed identification and control methods. You can find detailed information on Buckhorn Plantain, Broadleaf Plantain, Red Sorrel, Wild Violets, and Common Yarrow.

Yellow and Purple Nutsedge
Nutsedge is a summer perennial grass-like weed. They can be particular problematic since they cannot be controlled by broadleaf weed herbicides. Click here for weed identification, growth habits and control methods.

Ultimate Lawn Weed Identification Guide (with pictures)

As an Amazon Associate we earn from qualifying purchases made on our website. If you make a purchase through links from this website, we may get a small share of the sale from Amazon and other similar affiliate programs.

Weeds will not only hurt the look of your lawn, they will also rob your turfgrass of sunlight, water and other nutrients.

Identifying weeds can be difficult since there are so many different types that might invade your lawn.

  • Broadleaf weeds

A broadleaf weed will have wide leaves and a different vein pattern to a grassy weed. Some of the broadleaf weeds have different colored flowers that you can use to help identify what you have.

  • Annuals – These come up, seed and die all within one year
  • Perennials – Come back year after year – A perennial nuisance!

The tricky thing with weed control is that some herbicides will work on some weeds, but not for others so it’s critical that you identify exactly what you have so that you can apply the right treatment.

In this article, we’ll include some specific recommendations on how to get rid of certain weeds, but in general the best way to keep weeds out of your lawn is to practice proper lawn maintenance. Any spots where the turf is thin are more susceptible to weed growth. A thick and healthy lawn will crowd out any opportunities for weeds to grow.

  • Mowing to the correct height (not too short)
  • Irrigating the lawn properly
  • Minimizing thatch build up
  • Alleviating soil compaction
  • Fertilizing
  • Reducing shade

Identifying Grassy Weeds

Annual Bluegrass

Poa Annua, also known as Annual Bluegrass can be a real problem in lawns. It’s a winter annual that starts growing in the fall. It grows throughout the winter and then dies once temperatures start to increase.

Poa annua will stand out from your existing turfgrass and it can really ruin the look of your lawn. You might be able to spot Poa Annua in your grass by looking for light green spots. Poa annua is usually always a lot lighter than your surrounding turfgrass, although when it dies in the spring, it can leave nasty brown patches. When you get closer you should be able to identify it by looking at the distinctive seed heads which stick outwards.

How to Control Annual Bluegrass

Controlling Poa annua is tricky because it produces lots of seeds in a single season.

The best control for annual bluegrass is going to be a pre-emergent herbicide. Putting a pre-emergent down early in the fall before soil temperatures go below 70 degrees will prevent the seeds from sprouting in the winter time.

You can use the exact same product to control Poa Annua that you would use to control crabgrass, only you need to put it down at a different time of the year.

Crabgrass

Crabgrass is an annual weed which you may see in the mid to late summer.

It certainly sticks out like a sore thumb! You’ll often see it in areas of your lawn that are either stressed out or thin.

It has a lime green color, thick blades and looks quite similar to dallisgrass and tall fescue.

It starts out very small and grows much larger if allowed to spread.

As the plant matures, you should see a fork-like seed head at the end of the plant.

You’ll frequently see crabgrass growing along the edges of your sidewalks where it has space to grow.

How to Control Crabgrass

There are probably lots of crabgrass seeds sitting in your soil at any point in time.

Crabgrass is an annual and so these seeds germinate once soil temperatures reach around 55F.

If you want to prevent these seeds from germinating, it’s best to put a pre-emergent down before then.

It can also be controlled with a post-emergent product. Typically, the active ingredient will be quinclorac.

If you don’t want to use a post-emergent herbicide product on your lawn, you could just wait until the first frost when crabgrass will start to die out.

Dallisgrass

Dallisgrass is a bunch type grass that clumps together and it’s quite unsightly. It has broad blades that grow outwards. It often grows in a ring and you might see your turfgrass growing in the center where the dallisgrass strangles itself.

It looks quite similar to crabgrass although it has different seed heads. It’s out earlier in the season than crabgrass too!

How to Control Dallisgrass

Dallisgrass is arguably one of the worst weeds to have in your lawn. It has short rhizomes growing outwards making it hard to control.

Pre-emergents will not work since dallisgrass is a perennial.

Digging it up is going to be the best option.

You’re not going to be able to put down anything to kill dallisgrass that will not also kill your turfgrass.

Goosegrass

Goosegrass is a summer annual grassy weed that you’ll often see in areas of soil that have become hard, compacted or have poor drainage. For example, in areas where you have a lot of foot traffic or along sidewalks.

See also  How To Tell When Marijuana Seeds Are Ready To Harvest

Goosegrass can be found in lawns all throughout the US. Whether you have a warm or cool season turfgrass, goosegrass can still grow.

You might be able to make out a wagon wheel shape where the dark green leaves grow out from the silver/gray base.

The seed head looks a bit like a zipper.

It’s often misidentified as dallisgrass or crabgrass.

Goosegrass germinates once soil temperatures warm to around 65F. It needs a good amount of sunlight and moisture to grow.

How to Control Goosegrass

To prevent goosegrass, you’ll want to use a pre-emergent application in the early springtime and then maybe another application later in the spring.

You’ll want to apply your pre-emergent before soil temperatures reach 60F in order to prevent the seeds from germinating.

You can also use post-emergent applications to kill it off too. Just be careful when using roundup since it will also kill your turfgrass.

Nimblewill

Nimblewill (Muhlenbergia schreberi) is a warm season, perennial, grassy weed.

It’s commonly mistaken for bermudagrass and creeping bentgrass.

It’s found all across North America. It favours a shaded, damp environment although it will spread into areas of sunlight also. I’ve found that it spreads very easily.

Nimbelwill spreads though your lawn by seeds and stolons.

It’s certainly more noticeable in cool season grass types. Especially when it goes dormant once temperatures start to drop in the fall. During this time, nimblewill has a light brown color leaving inconsistent patches on your lawn which is not a good look.

One of the best ways to identify nimblewill is to look at your lawn in the morning when dew is sitting on your grass. If nimblewill is present, you’ll notice distinct patches.

How to Control Nimblewill

The fact that nimblewill is a perennial and has a stolon system makes it difficult to control.

For most grass types, the best way to kill nimblewill is to use multiple applications of tenacity. This will kill the nimblewill but not your turfgrass.

Of course, roundup can also be used but this will kill your turfgrass too.

Digging up nimblewill patches may also be appropriate.

Quackgrass

Quackgrass is a really thick and tough cool season, perennial grassy weed that sticks out like a sore thumb in a lawn. It has a wide blade and unlike crabgrass, it has a long root system with rhizomes that go deep into the ground.

It can be a real pain to deal with and it keeps coming back year after year. It does well in areas where turfgrass may struggle.

It looks quite similar to other grass types although its often lighter in color.

This weed grows very quickly and so it’s likely going to be a lot taller than any surrounding turfgrass you have. It spreads by rhizomes, much like yellow nutsedge.

Quackgrass can also be identified from its auricles that grasp the stem.

How to Control Quackgrass

Hand pulling quackgrass isn’t easy because of its long root system.

Much like crabgrass, the best way to control quackgrass is to establish a thick and healthy lawn to crowd it out.

Quackgrass is a perennial so if you want to use a post emergent, you’re likely going to have to use roundup.

Yellow Nutsedge

Yellow nutsedge (Cyperus esculentus) is a weed that looks a lot like other turf types. It also goes by nutgrass and watergrass although it’s not actually a grass.

Yellow nutsedge is often confused with having slightly yellow turf from having micronutrient deficiencies in the grass but in reality, it’s an actual perennial weed coming up.

At a first look, yellow nutsedge does lot a lot like grass but if you look closely enough, you’ll see it has a triangular stem made of three leaves indicating that it is a sedge and not a grass. The leaves are quite waxy too.

Yellow nutsedge tends to grow really fast. It’s really invasive too!

It reproduces by nutlets.

How to Control Yellow Nutsedge

It tends to show up in the early spring or summer which is usually the best time to control it. It’s much harder to kill later in the year once it starts sending out rhizomes.

One option of removing yellow nutsedge is to hand pull it during the early growth stages and when the soil is moist. Once the weed gets more established, this is going to be much harder to do.

It’s very unlikely that you’re going to get rid of yellow nutsedge by a single application of any product.

To remove nutsedge chemically, you’ll want to use a selective herbicide product like sedgehammer or prosedge.

Identifying Broadleaf Weeds

American Burnweed

American burnweed (Erechtites hieraciifolius) is native to the US and Canada although it can be found all over the world growing in a wide variety of conditions.

  • Fireweed
  • Butterweed
  • Pilewort

American burnwweed is a summer annual and a member of the daisy Asteraceae family.

American burnweed grows tall (300cm) and it grows particularly fast.

It’s often called fireweed because it’s found in disturbed areas affected by fire.

It has upright flower heads and alternate spiral leaves that can vary quite a lot in size and shape.

Not many things eat American burnweed. It has a low wildlife value and it can be toxic to some animals.

How to Control American Burnweed

American burnweed has a shallow root system so hand pulling it is a sensible option.

Broad spectrum herbicides are the most effective way to control American burnweed.

Herbicides with a single active ingredient tend to be less successful.

Black Medic

Black medic (Medicago luplina) is an annual weed that goes by a few other names too. You might hear it referred to as:

Black medic is a member of the legume family. It looks very similar to white clover and oxalis.

Like clover, it also has three leaflets although it differs from clover in that it’s center leaf sits up on a petiole.

Another feature of black medic is a small yellow flower.

Black medic can be a summer or winter annual.

How to Control Black Medic

Since black medic thrives in compacted soil, a good way to prevent black medic is to aerate your lawn to aleviate soil compaction.

Non-selective broadleaf herbicides are typically effective to kill black medic. Appling treatments in the early growth stages will yield the best results.

Carpetweed

Carpetweed (Mollugo verticillate) is a small, summer annual weed often found in lawns across north America.

Carpetweed is also called Indian chickweed or the devils grip.

It has a light green color with egg shaped leaves that form in whorls. At each node, there are between 3 and 8 leaves.

It has branches that lie low to the ground forming a prostrate mat. The branches are so low that running over carpetweed with a mower has no effect.

Carpetweed can cover quite a large area when it’s allowed to spread. It spreads by seeds at a very rapid rate, especially on thin turf.

In the late summer, you might see small white flowers.

Although carpetweed thrives in soil holding a good amount of moisture, in can also grow in drier soils too.

How to Control Carpetweed

Since carpetweed does well on thinning turf, maintaining a thick and healthy lawn is your best defence.

Post emergent herbicides that are effective for carpetweed are best applied when the plant is growing.

I’d recommend using glyphosate or quinclorac.

Prostrate Spurge

Prostrate Spurge (Euphorbia humistrata) is an annual weed that’s common to find in lawns across North America. This weed spreads by seeds that sprout in the spring and summer when soil temperatures reach around 75F. Of course, soil temperatures will vary by location and the surface.

Prostrate spurge dies off in the fall.

It grows very low to the ground and is often found in cracks between sidewalks, brick walls or disturbed areas.

The leaves have a dark green color and are oval-shaped. You may also notice milk sap appearing upon breaking the stem. This sap can actually be toxic to animals if ingested.

How to Control Prostrate Spurge

There are essentially two ways to control prostrate spurge. Either by using a pre or post emergent.

The best way to control spurge is to prevent it from sprouting in the first place by using a pre-emergent product.

It’s good to keep track of your soil temperature and apply your pre-emergent before it reaches 75F.

The best post emergent to use on spurge on other weeds found in cracks is 41% glyphosate (aka roundup).

Canada Thistle

Canada thistle (Cirsium arvense) is a creeping perennial that has rhizomes. It’s common to find and it is quite invasive but it doesn’t do well in areas where there is a lot of competition. This is why you will often see it without anything around it.

It is colonial so it tends to spread in large patches.

Canada thistle tends to do better in wetter areas although it can tolerate some dry conditions too.

It’s important to make a distinction between Canada thistle and other bi-annual thistles because the management can vary quite a bit.

One way that Canada thistle can be identified is by its creeping perennial roots.

It also has an alternate leave pattern and these are very prickly. You’ll notice that there are no spines on the stems at all, and the spines all point out from the edges of the leaves only.

You won’t see any hairs on the upper side of the leaf although you might see some small hairs on the lower side once the plant matures.

In the summertime, you will be able to see its distinctive purple flowers that are very small. These do not have any prickly spines on them at all. Later on in the season, these produce small white fluffy seeds which can blow off and disperse.

How to Control Canada Thistle

The best control for Canada thistle is to provide it with competition.

The best time to apply a control method to Canada thistle is in the fall when the plant is at its weakest.

Clover

Clover is a very common weed to find all over the US. It’s a short-lived perennial and a member of the legume family. It’s fairly easy to identify clover by looking at its round leaflets.

Clovers lawns used to be very popular. It stays green all summer, requires very little maintenance and it can grow in less than ideal soil conditions although it doesn’t tolerate lots of foot traffic very well. You don’t have to worry about mowing either!

One of the main benefits is that clover fixes nitrogen in a lawn. It takes it from the air and allows it to be utilized by your grass. For this reason, some people actually throw down lawn clover seed on purpose.

You might see the surrounding grass and plants have a darker green colour where there is clover growing.

How useful was this post?

Click on a star to rate it!

Average rating 4 / 5. Vote count: 1

No votes so far! Be the first to rate this post.