Weeds of Early Spring

April 5, 2023 by

With warmer weather comes plant growth. The most conspicuous plants in the lawn and landscape right now are winter annuals such as hairy bittercress (Cardamine hirsuta), henbit (Lamium amplexicaule), purple deadnettle (Lamium purpureum), and chickweeds (Stellaria media and Cerastium fontanum ssp. vulgare), to name a few. In lawns, these winter annuals are typically found in areas where the lawn was thin in September and October when these weeds germinated. Most winter annuals do not establish readily where the lawn canopy is dense. In ornamental beds they can be prolific unless the beds were recently mulched (which buries the seed), as there is plenty of open space and little competition from other plants.

Henbit flowering

Purple deadnettle flowering in early spring

Common chickweed in an ornamental bed

In the lawn, these winter annual broadleaf species can be easily controlled by herbicides that contain 2,4-D, MCPA, mecoprop, or dicamba. But keep in mind that these winter annual weeds are near the end of their life cycle and will be dead within 3 to 4 weeks even if no herbicide is applied. Exceptions include mouseear chickweed (Cerastium fontanum ssp. vulgare) and corn speedwell (Veronica arvensis) which can persist farther into the summer.

Corn speedwell in an ornamental bed

Perennials such as wild garlic (Allium vineale), star-of-bethlehem (Ornithogalum umbellatum), and lesser celandine (Ranunculus ficaria) are also noticeable this time of year. They are ephemerals that will return to dormancy within the next few weeks where they reside as bulbs for the summer, emerging again in late fall or mid-winter.

Star-of-bethlehem. Notice the white midrib on the leaf.

 

Star-of-bethlehem in a lawn

 

Lesser celendine in a lawn

Another ephemeral winter perennial is bulbous bluegrass (Poa bulbosa). This also emerges from bulbs in late fall and is dormant all summer. It is most conspicuous when in mid spring it produces what looks like an inflorescence, but is actually a collection of bulbils (small bulbs) and not flowers. Bulbous bluegrass is occasionally widespread in extremely low input lawns, but is more commonly found in small patches where disturbance and competition from other plants is low. I commonly see this at the base of tree trunks or between the sidewalk and road.

Bulbous bluegrass bulbils. Photo courtesy of Aaron Patton.

Bulbous bluegrass bulbs and leaves

Roughstalk bluegrass (Poa trivialis) is a perennial grass that is obvious this time of year due to rapid growth and light green color. There are no selective herbicide options for roughstalk bluegrass control. Except in wet and shaded areas where it is well-suited, roughstalk bluegrass growth tends to slow by late spring and it goes dormant in summer. If it is mixed well with other turfgrass species, this slow decline to dormancy is not noticeable. For more information about roughstalk bluegrass, see this recent blog.

Patches of roughstalk bluegrass in a lawn.

While winter annuals are nearing the end of their life cycle, summer annual weeds are just getting started. Japanese stiltgrass emergence (discussed in a recent blog) has been noted in several locations in central and southern NJ. It may be too late for preemergent herbicides to control stiltgrass. For more information on stiltgrass control, see this RCE factsheet.

Forsythia in full bloom

Soil temperatures and Forsythia full bloom we are now seeing suggests crabgrass (Digitaria spp.) emergence will begin within two to three weeks. Now is a good time to begin making preemergence herbicide applications. Based on what we know about crabgrass and other summer annual species, the mild winter is not likely to accelerate germination, since the seed is not active until soil temperatures are in the 50s. Other than using Forsythia spp. full bloom as an indicator, soil temperatures can be monitored, but the science doesn’t provide precise guidance on this. But as a general rule, once soil temperature consistently exceeds 55 °F at a 2” depth for at least few days, crabgrass seed germinates and emergence is often noted a few days later. Live soil temperatures can be found on the Rutgers NJ Weather Network. The 24-hr rolling average at locations we monitor in North Brunswick, NJ is between 48 and 54 degrees F, depending on sun exposure. See these links for more information on crabgrass control in the lawn for professionals, and homeowners.

Filed Under: Crabgrass, Golf Turf, Lawn, Sports Turf, Weed Control, Weeds

Japanese Stiltgrass Control in Turf

February 5, 2023 by

Japanese stiltgrass (Microstegium vimineum) is a C4 summer annual grassy weed commonly invasive to forests. It can be problematic in lawns. Often it is problematic in shaded areas adjacent to an infested forest. But we have observed infestations in full sun turfgrass areas where you would normally expect crabgrass to be the predominant summer annual. It seems this weed is becoming increasingly problematic in lawns. But why I am I writing about a summer weed in February?

Japanese stiltgrass in a lawn during late summer.

Japanese stiltgrass is the first summer annual grassy weed to emerge. Preemergence herbicides commonly used to control the summer annual crabgrass (dithiopyr, prodiamine, and pendimethalin) were effective for Japanese stiltgrass control in our research. However, stiltgrass emerges sooner than crabgrass and these preemergence herbicides are only effective when applied before stiltgrass emergence. In our 2022 research we applied these preemergence herbicides on March 11, 2022 in Pittstown, NJ. Stiltgrass typically emerges in March, often about a month before crabgrass. Germination of the seed and subsequent emergence is probably highly variable from year to year and depends on soil surface temperatures. Do not expect seedlings to be killed by frost. While Forsythia full bloom can be used as an indicator to apply crabgrass preemergence herbicides, there is no information available regarding soil temperatures or phenological indicators for stiltgrass emergence.

Japanese stiltgrass seedlings emerged in tall fescue turf in March

Our research found that while preemergence herbicides applied before stiltgrass emergence (in early March) were effective, those same treatments applied around crabgrass emergence in early May were not effective. A mixture of the postemergence herbicide Acclaim Extra (9 fl oz/A) and a preemergence herbicide was effective for stiltgrass control when applied in early May at crabgrass emergence. For stiltgrass control in June, July, and August, higher rates of Acclaim herbicide will be necessary for control. Acclaim Extra is the only product registered for postemergence stiltgrass control in turfgrass. Field research found it to be the most effective control option. See this RCE factsheet for more information about Japanese stiltgrass identification and other control options in non-turf areas.

https://njaes.rutgers.edu/fs1237/

In summary, to control Japanese stiltgrass, preemergence herbicides need to be applied a month earlier than is typical. If this is not feasible, tank-mixing preemergence herbicide with low rates of Acclaim Extra is an effective option.

Filed Under: Crabgrass, Lawn, Weed Control, Weeds

Green-up Started

March 17, 2020 by

Soil temperatures have been warming and reached the mid-40s °F last week at Rutgers Hort Farm No. 2 in North Brunswick NJ and are creeping into the upper-40s °F early this week. Dr. Clarke recommends that treatment of turf with a history of take-all patch be initiated when soil temperature averages 40 to 60 °F. Treatment of fairy ring should be initiated when average temperature is in the range of 50 to 55 °F. Waiting to treat beyond these soil temperature thresholds will increase the risk that control strategies are not as effective.

Table 1. Soil Temperature Data under Bentgrass Turf Mowed at 0.375-inch in North Brunswick, NJ on 17 March 2020 at 2:00 PM.

3-inch Depth Thatch-Soil Interface
Current 48 °F 50 °F
24-hour Average 45 °F 44 °F
5-day Average 47 °F 47 °F

 

Additionally, the Forsythia bloom started last week in central New Jersey, which Dr. Matthew Elmore recommends as a traditional phenological indicator for preemergence herbicide programs on turf.

Initial forsythia bloom in a home lawn in central NJ last week.

 

Filed Under: Crabgrass, Diseases, Golf Turf, Lawn, Uncategorized, Weed Control

Weed Control in Spring Seedings

April 9, 2019 by

The recent warm weather means its time to started on lawn and landscape projects. You may have plans to seed bare spots in the lawn that you didn’t get to in the autumn. These bare spots may be the result of fungal diseases, which were aplenty due to heavy rainfall in 2018. Summer annual weeds such as crabgrass or Japanese stiltgrass can out compete desirable species in the summertime and leave bare areas as well. While autumn is the ideal time to seed lawns in New Jersey, spring seedings can be successful if you have a plan to control summer annual weeds.

Crabgrass in a lawn

 

Weed competition from summer annual weeds is much more intense and is the main reason spring seedings are unsuccessful. In a mature lawn, you can apply a pre-emergence herbicide (crabgrass preventer) to manage weeds such as crabgrass and stiltgrass. If you recently seeded or have plans to, these crabgrass preventers are not an option.

If you are planning to seed this spring, using a starter fertilizer product that also contains the active ingredient mesotrione is an effective option when applied at seeding. It will control weed seedlings as they emerge without harming the grass you’ve seeded. One product for home lawns that contains mesotrione is Scotts® Turf Builder® Starter® Food for New Grass Plus Weed Preventer. Mesotrione is available for professional applicators as Tenacity® and other trade names. Products that contain siduron (Tupersan) are also an option for crabgrass control at seeding. Mesotrione and tupersan are not as effective as other pre-emergent herbicides such as pendimethalin, dithiopyr, and prodiamine that can be used on mature, well-established lawns.

After mesotrione is applied, weed seedlings and sometimes the turfgrass will appear bleached for 7 to 21 days after the application. The turfgrass will recover but most of the weed seedlings will not. Read the label carefully especially when using mesotrione and seeding fine fescue. Do not over apply mesotrione as it can damage grass you’ve seeded, especially perennial ryegrass. In areas of heavy weed pressure, mesotrione and siduron will likely not provide season-long crabgrass control. A second mesotrione application can be made 4-6 weeks after the initial or post-emergence herbicides that conitain quinclorac or fenoxaprop are also options if crabgrass develops mid-summer. Sprayable products sold for crabgrass control usually contain quinclorac or fenoxaprop.

Filed Under: Crabgrass, Lawn, Weeds

Goosegrass

January 15, 2018 by

Goosegrass is a summer annual weed of cool-season turfgrass that has become more problematic in recent years. My conversations with turfgrass managers suggest that goosegrass is firmly entrenched as a top 5 turfgrass weed issue of highly managed systems in the Northeast region. Crabgrass is more prevalent than goosegrass, but is less problematic in highly managed systems because it is effectively controlled with pre-emergence herbicide programs.

Goosegrass is easily identified by its prostrate growth habit and white, compressed sheaths. Photo: E. Reasor

Goosegrass and crabgrass are both summer annual grassy weeds. So why do pre-emergence herbicides typically used in cool-season turfgrass (dithiopyr, prodiamine, and pendimethalin) often provide inconsistent goosegrass control? It should be noted that the pre-emergence herbicide oxadiazon often provides excellent goosegrass control but is not widely used in cool-season turfgrass.

One reason is that goosegrass seedlings are thought to emerge 2 to 3 weeks later than crabgrass and continue germinating later in the summer. Indeed, the research we conducted this summer to evaluate seasonal goosegrass germination patterns found that the first goosegrass seedlings emerged in mid May, about 3-4 weeks after the first crabgrass seedlings. Interestingly, when we calculated the time it took 90% of the plants to emerge, there was a big difference between our two locations. Ninety percent of the goosegrass seedlings had emerged by early July at the golf course location, but at the research farm location just a few miles away (soil temperatures were similar) 90% emergence occurred in mid to late August. But I digress…

If goosegrass germinates later than crabgrass, making split applications of pre-emergence herbicides should provide more consistent control than single applications. However, my conversations with many in the turfgrass industry suggest is that goosegrass has become more problematic only in the last 5 to 15 years regardless of application strategy and mitotic-inhibiting pre-emergence herbicides have been used widely for over 25 years. So this would suggest some other factors are in play.

On the same golf course where we found 90% of the total goosegrass seedlings had emerged by early July, we evaluated several pre-emergence herbicide programs for goosegrass control in 2017. Treatments were applied in early May. By mid June we noticed that plots treated mitotic-inhibiting herbicides had as much goosegrass as non-treated plots. Meanwhile, plots treated with oxadiazon (a different mode of action) had almost no goosegrass. For reasons mentioned earlier, I would not expect these mitotic-inhibiting herbicides to provide excellent goosegrass control, but they should be providing some control, especially in mid-June.

We collected seed from the site in December 2016 and we compared this seed to a population collected from our turfgrass research farm using a controlled experiment in the greenhouse. We found that the golf course population was not controlled by a mitotic-inhibiting herbicide, but the research farm population was 100% controlled (figure below). Both populations were 100% controlled by an herbicide with a different mode of action.

Pots treated with a mitotic-inhibiting pre-emergence herbicide on the day of seeding. The wild type population was collected from our turfgrass research farm. The golf course population was collected from a golf course with a history of mitotic-inhibiting herbicide use.

In the Southeast, herbicide resistance to mitotic-inhibiting pre-emergence herbicides (dithiopyr, prodiamine, and pendimethalin) and oxadiazon has been implicated as the cause of goosegrass issues on many golf courses and was first reported over 30 years ago in 1984 (by Mudge et al.). However, I’m not aware of resistance to mitotic-inhibiting herbicides in the Northeast despite heavy reliance on these herbicides for annual grassy weed control.

Goosegrass resistance to pre-emergence herbicides typically begins with one plant surviving the application due to a genetic mutation. The goosegrass plants with the mutation probably goes unnoticed and sets seed, which leads to a small patch of plants the next year when the same pre-emergence herbicide is used again and does not control plants with the mutation. The patch may become larger each year as that population is spread throughout the property via seed eventually becoming problematic.

At the recent NJ Green Expo in Atlantic City in December, I briefly discussed the topic of goosegrass resistance to pre-emergence herbicides during a panel discussion. Responses suggested this is an issue that deserves more investigation.

If you suspect that resistance to pre-emergence herbicides is an issue on your property, please contact me via email (matthew.elmore@rutgers.edu) or Twitter (@RUturfweeds). Your will be extremely helpful to help determine if this is a widespread issue and potentially collect plants/seed samples for further testing.. All correspondence will be kept confidential.

Filed Under: Crabgrass, Golf Turf, Weed Control, Weeds

Crabgrass and Goosegrass Control in Fine Turf

June 25, 2017 by

Over the past 7 to 10 days, warm-season weeds have really turned the corner and are growing rapidly. It’s probably no coincidence that 5-day average soil temperatures finally pushed past 70 degrees about 10 days ago in central NJ. Until last week, most of the crabgrass I observed was growing slowly with a chlorotic appearance. Now it has taken on the more characteristic lime green hue and is growing more rapidly than surrounding cool-season turf. Where previously it was mostly present in thin area of turf, it’s now beginning to make an appearance in dense stands of fine turf such as fairways and greens.

Smooth crabgrass with its characteristic hue in a poor stand of perennial ryegrass on June 23, 2017.

With this post, I’m going to focus mostly on control in in creeping bentgrass where herbicide options are limited. Now is a good time to scout historically problematic areas for small crabgrass and goosegrass plants. If left uncontrolled and allowed to tiller, crabgrass control in creeping bentgrass fairway turf is difficult and with risk of bentgrass injury.

Leaf stage smooth crabgrass in an annual bluegrass/creeping bentgrass fairway.

Fenoxaprop (Acclaim Extra) can be applied at 3.5 fl oz/A for control in bentgrass fairways. This rate is 8 to 10X lower than what can be applied to ryegrass, bluegrass and tall fescue to control larger crabgrass plants. At the 3.5 fl oz/A rate, multiple applications on 2 to 3 week intervals may be required to provide control of small leaf-stage crabgrass. If crabgrass is allowed to tiller, even multiple applications of fenoxaprop at rates labeled for use in bentgrass fairways may be a losing battle, so scouting is important. Quinclorac (Drive XLR8, Quinclorac 75DF) is an option to control tillered plants in bentgrass. At rates labeled for use in creeping bentgrass multiple applications may be required. Refer to the label for more information about rates, turfgrass tolerance and adjuvants.

Fenoxaprop will also provide suppression or control of small goosegrass plants. However, once goosegrass begins to tiller, fenoxaprop is less effective at low rates.

Topramezone (Pylex) is an effective herbicide for goosegrass control in cool-season turf. However, in creeping bentgrass fairways, Pylex is labeled for application at up to 0.25 fl oz/A. Tolerance may vary depending on bentgrass cultivar and other management practices. Topramezone causes bleaching of susceptible plant tissue and while limited bleaching is not detrimental to fairway turf from an agronomic perspective, it is very noticeable to even a casual observer. I hate to copy instructions from a bottle of carpet cleaner, but it’s a good idea to make an application to a small area of bentgrass and wait 10 to 14 days to make sure the bleaching you observe is acceptable. My experience with low rates of topramezone for goosegrass control is limited, but multiple applications may be required depending on plant size. Include methylated seed oil or crop oil with Pylex per the product label. Other cool-season grasses such as Kentucky bluegrass, ryegrass, tall fescue and fine fescue are more tolerant than creeping bentgrass and application at higher rates is permitted.

Crabgrass and goosegrass will continue to germinate throughout the summer. If you are observing significant breakthrough in areas already treated with a pre-emergence herbicide consider applying a pre-emergence herbicide with a different mode of action than previously applied. One example is Anderson’s Goosegrass/Crabgrass Control, which contains oxadiazon. Oxadiazon is a PPO inhibiting herbicide, not a mitotic inhibiting herbicide like most other pre-emergents (i.e., bensulide, dithiopyr, pendimethalin, prodiamine). Anderson’s Goosegrass/Crabgrass Control should be applied to dry turf and is labeled for use on bentgrass putting greens. Another example of an herbicide with a different mode of action is Tower (dimethenamid-P). Tower is labeled for use on bentgrass fairways and tees. Read the label for more information on turfgrass tolerance to both of these products.

For information on crabgrass and goosegrass ID and control other turfgrass areas, see this previous post.

The mention of trade names and rates is for educational purposes and does not imply endorsement by the author, Rutgers Center for Turfgrass Science, or the New Jersey Agricultural Experiment Station. Always defer to the product label for instructions on properly applying an herbicide.

Filed Under: Crabgrass, Golf Turf, Weeds

Weeds off to a Slow Start

May 26, 2017 by

Despite a quick start to the spring, soil temperatures remain low across the much of the state. Average soil temperatures (3-inch depth) have been hanging around the mid 60s in central NJ and many warm-season weeds such as crabgrass have hardly developed despite germinating over 6 weeks ago. This crabgrass at our research facility has not advanced past the leaf stage and I have observed this across the region over the past few weeks.

Smooth crabgrass in the leaf stage

The peak of annual bluegrass seedhead production has passed. It was a very difficult spring to properly time ethephon applications for optimum seedhead suppression. If the results of our seedhead suppression research trial are indicative of the region, then I suspect those that made a fall (December at the snow mold fungicide timing) application of ethephon were happy with suppression. Spring-only applications did not perform very well in our research.

A very seedy annual bluegrass putting green at Hort. Farm No. 2

When warmer weather arrives, warm-season weeds will develop rapidly. If you are relying exclusively on post-emergence herbicides for crabgrass control, an application of a post-emergence herbicide in the next few weeks may be warranted. This will only control what has already germinated and not what will emerge as we continue into the summer, so additional applications will be necessary. Especially if using fenoxaprop (Acclaim Extra, Last Call), lower herbicide rates often can be used when treating smaller plants. Mesotrione (Tenacity) is another post-emergence crabgrass herbicide that is most effective on smaller plants. Quinclorac (Drive XLR8, Quinclorac 75DF) is another post-emergence option but is often more effective against larger (> 4 tiller) plants than the smaller plants present right now. Topramezone (Pylex) has efficacy some against crabgrass but is an extremely effective product for goosegrass control. See the herbicide labels for more information.

We observed goosegrass emergence two weeks ago at certain sites but not others. This event is not particularly relevant for those who applied a pre-emergent herbicide. However, you may want to scout areas with a history of goosegrass problems to make sure your pre-emergence herbicide is working. Goosegrass seedlings can be difficult to differentiate from crabgrass seedlings. Goosegrass seedlings have a ridged adaxial leaf surface (ridges look similar to perennial ryegrass) and a blunt leaf tip while crabgrass seedlings are relatively smooth with a sharper leaf tip. If you applied a pre-emergence herbicide and are already seeing goosegrass germination please contact me.

Goosegrass seedlings

If you plan to make an herbicide application to control broadleaf weeds, the weather continues to be ideal for control and growth of the cool-season grass into voids. This is especially true for the summer annual knotweed.

Prostrate knotweed observed mid-May in New Brunswick

 

Prostrate knotweed is more easily controlled now while it is still relatively immature. Standard three-way or other broadleaf herbicides that contain 2,4-D may not provide complete control. So in the case of severe infestation, products that contain triclopyr (e.g., T-Zone, Battleship III, 4-Speed XT, Cool Power, others) will provide more control. Cultural practices such as aerification to reduce compaction and improve conditions for turf growth are also essential. For more information on whether you will disrupt the pre-emergence herbicide barrier by aerifying, see this information from Dr. Aaron Patton.

To Aerify or Not to Aerify when Using a Preemergence Herbicide

 

Sedges and Kyllingas

This week I visited several golf courses and other sites along the Garden State Parkway from Exit 9 (Cape May) to Exit 171 (A few miles from the NY State line. In terms of plant development, northern NJ seems to be about a week behind central NJ and southern NJ seems to be a week or two ahead of central NJ. The most noticeable difference across locations is the difference in kyllinga emergence from dormancy. In southern NJ, kyllinga is close to full emergence while kyllinga northern NJ is at approximately 50% emergence. In all locations, but especially those in southern NJ, now would be a good time to begin making applications if you haven’t already.

False-green kyllinga dominating a stand of tall fescue

False green kyllinga (foreground) has a lime green color compared to the tall fescue (background).

 

Our research indicates that halosulfuron-methyl and imazosulfuron are effective options for control. Multiple applications will likely be necessary for effective control. Make follow-up applications after you observe re-growth from the previous application (usually 3 to 4 weeks later). For more information see this previous blog post by Dr. Murphy. https://turfblog.rutgers.edu/?p=934#more-934.

Filed Under: Crabgrass, Golf Turf, Lawn, Sports Turf, Weed Control, Weeds Tagged With: , ,

Hurry Up and Wait. Now Go!

April 2, 2017 by

At the beginning of March we were potentially a week or two away from annual bluegrass seedhead emergence thanks to an extremely warm February. Cooler temperatures prevailed and significant snowfall across much of the Northeast brought soil temperatures down and put the brakes on annual bluegrass development for a few weeks. It’s now the beginning of April and we are very close to annual bluegrass seedhead emergence on putting greens in central New Jersey. Parts of northern New Jersey appear to be about a week behind the New Brunswick area.  If you haven’t already applied ethephon (i.e., Proxy, Ethephon 2 SL, Oskie) for seedhead suppression, this week might be ideal (see previous post for more information) for most courses in New Jersey.

Warmer temperatures this week will likely bring average 24-hour soil temperatures (one inch depth) into the 50s and turf will begin to grow more rapidly. Emergence of summer annual weeds is not far away. I first noticed prostrate knotweed emergence in mid February. These early germinating plants survived the winter weather and will continue to develop this week.

Prostrate knotweed seedlings

Note that knotweed seedlings will have two seed leaves and crabgrass will have only one.

Prostrate knotweed seedling with two seed leaves

 

Smooth crabgrass seedling with one seed leaf

I have not observed crabgrass emergence, even on south-facing slopes. I spent the latter part of last week in Washington D.C. and could not find any crabgrass along sidewalks and bare areas there either.

Crabgrass emerging with one seed leaf (in a previous year)

Depending on your location, forsythia may or may not be a reliable phenological indicator for crabgrass germination this year. In a normal year, pre-emergent herbicides (except for dithiopyr (Dimension), which can control crabgrass up to the pre-tiller stage) should be applied when forsythia is in full bloom because crabgrass germination will occur shortly thereafter. However, extremely cold temperatures killed or injured many forsythia flowers in central Jersey and areas south.

In northern New Jersey I’ve observed forsythia plants still in the bud stage and in this case they are likely to be effective indicators. Especially this year, it is important to use multiple forsythia plants because the bloom timing is affected by location among other factors. Plants that bloomed early were injured by the winter weather, but others were unaffected as this photo from @samcamuso demonstrates.

Soil temperature at a 1-inch depth has been reported as a reliable indicator of crabgrass germination assuming soil moisture is adequate. In a three-year study, Fidanza et al. (1996) found that crabgrass began to emerge when the soil temperature at a 1-inch depth averaged 57 to 63 degrees during a 7-day period. Soil temperatures at our research center in North Brunswick have been well below this threshold as of this writing. At this time we are holding off on making pre-emergent applications to our research trials. However, in southern New Jersey soil temperatures are warmer and crabgrass will germinate sooner. In these areas, making a pre-emergence herbicide application soon would be timely. If you are worried you may be too late, scout bare areas with crabgrass carcasses, especially those on south-facing slopes, as crabgrass will germinate earlier in these areas.

Making pre-emergent herbicides applications early is not thought to reduce efficacy. However, if you are using dithiopyr (i.e., Dimension) it’s a good idea to wait until shortly after emergence and take advantage of the early post-emergence efficacy this product provides against crabgrass.

Of course don’t forget to consider your potential renovation/seeding projects this spring. If you are planning on seeding, do not apply any pre-emergence herbicide.

Literature Cited

Fidanza MA, Dernoeden PH, Zhang M (1996) Degree-days for predicting smooth crabgrass emergence in cool-season turfgrass. Crop Sci. 36:990-996.

Filed Under: Annual Bluegrass, Crabgrass, Golf Turf, Lawn, Weather Conditions, Weed Control, Weeds

Crabgrass Emerging

June 19, 2014 by

Crabgrass has been emerging for several weeks now, depending on the exposure. Warmer and more open turfs will likely have more advanced (larger) plants while cooler and denser turfs will have smaller plants.

Relatively small crabgrass plants (most pre-tillering stage) emerging from a footpath on June 11th.

Relatively small crabgrass plants (most pre-tillering stage) emerging from a footpath on June 11th.

 

Management options for this weed at this point in the season range from doing nothing to [Read more…]

Filed Under: Crabgrass, Golf Turf, Lawn, Sports Turf, Weed Control

Crabgrass Emerging

June 13, 2013 by

Back on May 24, I posted about my observation of crabgrass emerging in areas that had very thin turf cover and very high levels of crabgrass seed in the soil. Crabgrass is now emerging from areas with healthier turf and good density (and has not received a preemergence herbicide application). Recent and forecast rains are likely to [Read more…]

Filed Under: Crabgrass, Golf Turf, Lawn, Sports Turf
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