Rutgers Turf Blog

Registration is open for the 35th Annual Rutgers Turfgrass Symposium, to be held on March 19, 2026

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The Center for Turfgrass Science at Rutgers University will host the 35th Annual Rutgers Turfgrass Symposium on Thursday, March 19, 2026, in room 101 of the Institute for Food, Nutrition and Health building. Oral presentations will run from 9:00 AM to 4:00 PM. Dr. Eric Watkins (Department of Horticultural Science, University of Minnesota) will present a keynote address entitled “Investigating New Strategies for Turfgrass Survival in a Changing Winter Climate.” This year’s symposium will focus on modern approaches to research in turfgrass science.

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View the Tentative Agenda (PDF)

Registration is open for the 34th Annual Rutgers Turfgrass Symposium, to be held on March 20, 2025

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The Center for Turfgrass Science at Rutgers University will host the 34th Annual Rutgers Turfgrass Symposium on Thursday, March 20, 2025, in room 101 of the Institute for Food, Nutrition and Health building. Oral presentations will run from 9:00 AM to 4:00 PM. Dr. Leah Brilman (Director of Product Management and Technical Services at DLF-Pickseed) will present a keynote address entitled “40 Years of Cool-Season Turfgrass Improvement and Goals for the Future – The Importance of Rutgers-Industry Cooperation.” This year’s symposium will focus on modern approaches to research in turfgrass science.

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View the Tentative Agenda (PDF)

Fall Brings Opportunities for Perennial Weed Control

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Cooler fall weather is a prime opportunity to control warm-season grassy weeds like nimblewill (Muhlenbergia schreberi). Fall is a particularly good time to control nimblewill because the increased competitiveness of cool-season turfgrass enhances the effectiveness of herbicide programs.

Blueish-green mat appearance of nimblewill in cool-season turfgrass.

Nimblewill is a warm-season perennial grass that thrives in shady, moist environments but is commonly found in sunny areas as well. It spreads through stolons (above-ground runners) and can form dense mats, making it difficult to remove once established. Nimblewill is most obvious during the late fall and winter, as it turns brown and goes dormant at first frost, making it more noticeable in cool-season turf.

Dormant nimblewill in a thin stand of cool-season turfgrass.

Nimblewill resembles both bentgrass and bermudagrass. Bermudagrass is also a perennial warm-season grass that goes dormant after the first frost, but is often found in sunny, drier areas. Bermudagrass is coarser and challenging to pull out of the ground than nimblewill, which has a shallower root system. While all three grasses spread through stolons, bermudagrass also has rhizomes, adding to its resilience. Bentgrass has thin stolons that creep along the ground. Nimblewill stolons appear wiry as they are often stems that fall to the ground and root at the nodes. Nimblewill often has a hairy collar, while the bentgrass collar lacks hairs, and bermudagrass hairs are more conspicuous. Nimblewill has a shorter membranous ligule than bentgrass, and the bermudagrass ligule is hairy.

Nimblewill collar with hairs

Selective herbicide options for nimblewill control include mesotrione (e.g., Tenacity),  topramezone (Pylex) and SpeedZone (2,4-D + MCPP + dicamba + carfentrazone). Although SpeedZone is often considered a broadleaf weed herbicide, we found it provides nimblewill control when applied in September and October. Mesotrione and topramezone are more compatible with seeding of cool-season turfgrasses, but are less effective for broadleaf weed control than SpeedZone. Another option is a single application of the non-selective herbicide glyphosate if you plan to reseed. Regardless of the herbicide selected, a multi-application program over two years will provide more control than single applications, targeting regrowth from stolons and any nimblewill seedlings remaining in the soil seedbank after the perennial nodes are killed. In addition to herbicide programs, enhancing the competitiveness of desirable turfgrass should be part of an integrated approach. While this approach has not been evaluated for nimblewill control, large increases in long-term control of other warm-season perennial weeds including dallisgrass, bermudagrass, and false-green kyllinga have been found when fall seeding and herbicide programs are combined. For nimblewill, this integrated approach might include interseeding, or simply applying more nitrogen fertilizer (up to two applications of 0.9 lbs N/1000 ft2 in the fall) around herbicide applications if existing cool-season grass already mixed into patches of nimblewill. Check herbicide labels for compatibly with seeding.

Ming-Yi Chou

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Assistant Extension Specialist in Turfgrass Pathology, Dept. of Plant Biology

Ming-Yi-Chou headshot.

My research program focuses on sustainable cool-season turfgrass disease management, aiming to provide solutions for effective disease control while minimizing the unintended impact of disease control practices (i.e., fungicides).

To achieve this goal, my team strives to understand the short- and long-term effects of management practices on the pathobiome (disease-causing or -facilitating microbial community) and beneficial microbiome, leveraging multi-omics, digital PCR, and applied machine-learning techniques.

To facilitate real-world and practical impacts, my team also aims to translate biological findings and fundamental developments into accessible decision support tools for turfgrass managers through disease predictive models and pathogen quantification assays.

In addition, my team also directs a turfgrass disease control products efficacy evaluation program collaborating with industry partners. This program is among the largest of its kind in the U.S., testing 300-500 turfgrass synthetic and biological fungicide treatments against all major diseases each year.

All of these research and development activities directly fuel my outreach efforts to provide the latest science-based information and education to the turfgrass managers in New Jersey, the Northeast, and beyond.

More About Ming-Yi Chou
Ming-Yi Chou Lab
Evaluation of fungicide efficacy against gray leaf spot (Pyricularia oryzae) in the field.
Evaluation of fungicide efficacy against gray leaf spot (Pyricularia oryzae) in the field.
Development of turfgrass disease predictive models using machine-learning algorithms.
Development of turfgrass disease predictive models using machine-learning algorithms.
Field validation of the snow mold predictive models on a golf course.
Field validation of the snow mold predictive models on a golf course.

What Does the Fling with Spring Mean for Weed Emergence?

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The region enjoyed warmer than average temperatures last week and into the weekend before things cooled off on Monday and now remain seasonal. While warmups like we saw last week are not uncommon in March, the extended 5- to 6-day duration of warm weather has Forsythia in full bloom across much of the region. What does this mean for emergence of summer annual weeds like crabgrass?

Forsythia in full bloom.
Forsythia in full bloom

The science on this topic is not settled, but found phenological indicators like Forsythia are as good or better than using soil temperatures or growing degree-days (calculated from air or soil temps) to predict crabgrass emergence. When Forsythia is in full bloom, it is a warning that crabgrass emergence is near and it is a good time to start making preemergence herbicide applications, particularly for those not using dithiopyr and others that need multiple weeks to get applications completed. I suspect that for most of us, except potentially in southern NJ, we will need another warm period of high temperatures in the 60s and 70s to see crabgrass emergence. For those relying on prodiamine and pendimethalin, it is not too late, but also not too early to make applications. That said, forecasting crabgrass emergence is less certain than predicting the weather.

In combination with using uncertain predictions, check sentinel areas for crabgrass seedlings to see if emergence has started. Sentinel areas I go to are thin turf on south-facing slopes since they warm faster than other turf areas. Areas near paved surfaces warm too rapidly compared to turf and are not useful. If you see emergence in sentinel areas, make preemergence applications ASAP.

A crabgrass seedling

Japanese stiltgrass emergence

While I have not seen crabgrass seedlings, Japanese stiltgrass has emerged in central NJ. Stiltgrass emerges before crabgrass, although temperatures that trigger emergence or phenological indicators are not understood. Typically have seen it emerge 3 to 4 weeks before crabgrass.

Japanese stiltgrass seedlings in lawn on March 18, 2024 in East Brunswick, NJ.

Particularly in central and southern NJ and the NY metro area, do not expect complete control of Japanese stiltgrass if you have not applied your preemergence herbicide and had rainfall to get it into the soil. For more information on Japanese stiltgrass control in lawns, see this blog post.

Good Time to Assess Drainage

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The soil that supports our lawns, sports fields, golf courses, and other land uses begins to recharge (store) with water as the evapotranspiration rate drops off during autumn and continues to decline to a very low rate during winter. Water storage in soil is good since that provides the water needed to support green-up and re-initiation of plant growth in the spring. However, an excessive accumulation of water is an indicator that one or more conditions in the landscape are restricting drainage.

Poor drainage in a softball field
A depression in the grade of an outfield causing ponding of water on a softball field.

Observing the drainage capacity of landscapes during late winter and early spring 2024 should be highly effective at determining whether corrective action is needed to improved drainage. We have experienced above normal precipitation In New Jersey during three of the last six months. September 2023 precipitation averaged 7.55” across the state, which was 3.39” above normal and ranks as the 9th wettest September. December 2023 precipitation was the wettest 12th month on record dating back to 1895. Statewide, precipitation averaged 8.20”, which was 3.93” above the 1991–2020 normal and was 0.33” above the previous wettest December in 1996. January 2024 was 6th on record dating back to 1895. The statewide 6.39” of rain and melted snow was 2.90” above the 1991–2020 normal. See https://www.njweather.org/news for more weather details.

Thus, autumn and winter precipitation has certainly recharged our soils to be at or very near field capacity, Field capacity refers to the water remaining in a soil after it has been thoroughly saturated and allowed to drain freely, usually for one to two days.

With our soils essentially full of water, any additional precipitation during the remainder of the winter and into early spring will provide us a good assessment of drainage. Soil that is freely drained will be wetted after precipitation but will return to a well drained condition (field capacity) within one to two days. Slow to drain areas will become soggy and possibly pond water for more than two days. The longer excess water lingers beyond 2 days within or above the soil, the poorer the drainage.

It is a good practice to scout your landscapes during this time of year and watch for areas that remain soggy or ponded well beyond 2 days after rain. Once you find poorly drained areas the key to improving drainage is to identify where the excess water is coming from and to intercept it before impacting the turf and other landscape plants. The two essential concepts behind good drainage designs are to protect soils from becoming ponded and/or the root zone from becoming waterlogged. Drainage solutions range from re-contouring the landscape (shed excess water through surface drainage) to installing a network of below-ground pipe drainage (intercept excess subsurface water).

Summer Weeds

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It finally feels like summer in New Jersey. Rain, humidity, and warmer temperatures, especially at night, mean that warm-season weeds are growing quickly. Of particular concern are summer annuals like crabgrass, goosegrass, and spurges. Yellow nutsedge and false-green kyllinga are warm-season perennials are also enjoying the weather. These weeds are now growing more quickly than the turfgrass so they are easier to spot a few days after mowing.

Notice the light green leaves of crabgrass in a lawn in early July. Plants this size are still relatively immature and easier to control.

Particularly for summer annuals, walking the area and looking carefully for these weeds will allow you to control them while they are still immature. In this weather these weeds will mature quickly, and once they do herbicide programs are less successful and hand weeding becomes more difficult.

For more information on crabgrass and goosegrass control for professionals see: https://njaes.rutgers.edu/fs1309/

For information on crabgrass control in the home lawn for non-professionals see: https://njaes.rutgers.edu/fs1308/

For more information on false-green kyllinga control see: https://njaes.rutgers.edu/fs1290/

For more information on yellow nutsedge control see this previous blog post: https://turfblog.rutgers.edu/?p=1431

The broadleaf weed spurge (Euphorbia spp.) in a lawn in early July.

Time to Control Yellow Nutsedge

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Now is the ideal time to control yellow nutsedge (Cyperus esculentus). This plant is a perennial that grows best during the heat of summer and survives the winter through underground tubers. While the drought may have limited nutsedge emergence in unirrigated areas, it is visible and rapidly growing in irrigated beds and lawns.

Yellow nutsedge and other sedges look similar to grasses, but sedges have a unique triangular stem. This triangular stem results in a three-ranked leaf arrangement. While many sedge species can be found in the lawn and garden, yellow nutsedge is the only perennial sedge found in New Jersey and is far more difficult to control than annual sedges.

A cross section of a yellow nutsedge stem. This triangular shape is unique to sedges.
A yellow nutsedge plant from above. Notice the leaves at 120-degree angles from one another forming a three-ranked leaf arrangement.

Yellow nutsedge is a perennial through tubers. The aboveground plants and rhizomes are killed each winter and the tubers are the source of the infestation each spring. Initiating nutsedge control measures now will prevent the formation of new tubers and make this weed less problematic in the future.

Yellow nutsedge tubers.
Yellow nutsedge tubers. The brown tubers are mature while the white tuber is immature.

Lying dormant during winter up to several inches below the surface, nutsedge tubers sprout in spring, giving rise to new plants aboveground. These plants then produce rhizomes (underground stems) that form more plants and tubers for next year (and beyond). If left unchecked, a single tuber sprouting in spring can produce thousands of new tubers by the end of the summer.

A severe yellow nutsedge infestation.
A severe yellow nutsedge infestation in a recently mulched landscape bed. The open space between ornamental plants allows ample sunlight and nutsedge thrives.
Yellow nutsedge in a lawn in early June.
Yellow nutsedge in a lawn in early June is relatively inconspicuous. The thin and light green leaves are the nutsedge. The nutsedge will become more obvious as temperatures increase through the summer.

Implementing strategies to control nutsedge now before it forms tubers is critical to get rid of this weed. Right now in early June, yellow nutsedge shoots are producing rhizomes but have probably not yet begun producing tubers. Treating nutsedge with herbicide now and again in 6 to 8 weeks (if green shoots are visible) is an ideal strategy.

Yellow nutsedge rhizomes.
Yellow nutsedge rhizomes

The herbicide halosulfuron can be used for selective sedge control in both lawns and ornamental beds. It is safe to the turfgrass and can be applied around ornamental plants. Numerous formulations are available for professionals. A user-friendly product for non-professionals is Sedgehammer®+, which is widely available and sold in small pouches with the exact amount to mix into a gallon of water for a pump sprayer. This product also contains the surfactant halosulfuron needs for best nutsedge control. Halosulfuron is systemic (moves in the plant), but slow to work, so it will be 2 to 4 weeks before there are noticeable results.

Nutsedge tubers can persist for several years in the soil, so one year of herbicide treatment will not eliminate yellow nutsedge. But treating now and once more later in the season will reduce the severity of the problem in future years. This approach is better than waiting until mid or late summer for the first application.

Combine herbicide programs with non-chemical management to improve control. More than other weeds, nutsedge is poorly competitive in shade and in dry soils. You may notice nutsedge in thinner areas of the lawn. Focusing on turf management practices that increase lawn canopy density during the autumn (e.g. N fertilization and seeding) will result in fewer herbicide applications the future. Do not apply halosulfuron sooner than 4 weeks before seeding turfgrass. Modifying landscape beds to reduce large spaces between plants can be similarly combined with herbicide programs for better long-term control. Fixing poorly drained areas and being careful not to over irrigate may also help manage nutsedge.

It is possible to eliminate yellow nutsedge by hand weeding or by using OMRI-approved herbicides (which are non-systemic). But keep in mind, pulling shoots or killing with non-systemic herbicides usually signals the tubers to produce many new shoots. So, hand-weeding or spraying more frequently than with systemic herbicides like halosulfuron is necessary. Digging the tubers is not practical as they are several inches underground and many are too small to be easily seen.