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K-State Turf and Landscape Blog

Month: March 2020

Flowering Ornamentals and Crabgrass Emergence

By Jack Fry and Ward Upham

Efficacy of some preemergence herbicides is strongly dependent upon the timing of application relative to crabgrass emergence.  For example, application of a preemergence herbicide that has a relatively short residual, such as pendimethalin, closer to crabgrass emergence, will extend the period of time which the herbicide is effective.  Herbicides with longer residuals, such as prodiamine (Barricade), are often applied well before crabgrass emergence, and can even be effective if applied late in the previous autumn.

In our climate, calendar dates don’t always adequately identify crabgrass emergence or herbicide application.  Biological indicators, such as flowering ornamentals, may be useful for predicting crabgrass emergence and preemergence herbicide application.

From 1995 to 1997, K-State researchers worked with those at the Univ. of Nebraska to identify ornamentals at each location which best represented crabgrass emergence and preemergence herbicide application time.  Ornamentals evaluated were bridal wreath spirea, callery pear, daffodil, flowering quince, forsythia, iris, lilac, redbud, saucer magnolia, tulip, and vanhoutte spirea.  Obviously, there may be ornamental cultivar differences in blooms, so this was an average of those observed.  In addition, crabgrass can vary in rate of emergence, but getting an herbicide out before the first plants emerge is preferable.  For this article, we’ll focus on results in Kansas.

Crabgrass emergence in bare soil and thin turf was evaluated at the Rocky Ford Research Center in Manhattan. Over three years, the earliest date of crabgrass emergence in bare soil was April 15 1995, whereas the latest date was May 9, 1996.  In the thin turf (10% bare soil evident while standing), the earliest date of emergence was May 5, 1997 and the latest date was May 22, 1995.

Withering of blooms was a better indicator of crabgrass emergence, particularly in thin turf.  In this case, we looked at bloom wither and then compared it to a date 2 weeks prior to emergence.  This 2-week window would allow time for the herbicide to be applied. In Kansas, withering of most ornamentals was not useful for estimating emergence of crabgrass in bare soil, as emergence often occurred before blooms had withered. However, a date 2 weeks prior to  crabgrass emergence in bare soil could be estimated by adding 6 to 12 days to the date of daffodil wither.

Bloom wither of flower ornamentals was used as a date to determine time of application of short-residual preemergence herbicides (a date 2 weeks prior to crabgrass emergence)

 

Flower wither of all ornamentals could be used indicators of emergence (and herbicide application date) in thin turf in Kansas (see Table 1 below). For example, by adding 28 to 33 days to the date of forsythia bloom wither, you will estimate a date 2 weeks prior to crabgrass emergence in thin turf, which would allow time for preemergence herbicide application.  This timeline is quite different from the often used theory that herbicides must be put down at the time forsythia blooms.  Ultimately, biological indicators, along with soil temperatures, will be better indicators of for crabgrass emergence and application of short-residual preemergence herbicides than calendar dates.

Table 1.  Ornamentals and the number of days to be added to flower wither to estimate the date 2 weeks prior to crabgrass emergence in thin turf.  Data were based upon observation of ornamental blooms and crabgrass emergence for a 3-year period.

Ornamental Number of days to add to bloom wither to estimate the date 2 weeks before crabgrass emergence (range allows for standard error)
Bridal wreath spirea 4 to 13
Callery pear 32 to 41
Flowering quince 36 to 42
Forsythia 28 to 33
Iris 8 to 15
Lilac 17 to 22
Redbud 25 to 32
Saucer magnolia 28 to 32
Tulip 21 to 29

 

Note – This article is based upon:

Fry, J., S. Rodie, R. Gaussoin, S. Wiest, W. Upham, and A. Zuk.  2001.  Using flowering ornamentals to guide preemergence herbicide application in the Midwest U.S.  International Turfgrass Society Research Journal.  p. 1009-1012.

The Star-of-Bethlehem makes an appearance….

By Brooke Garcia (Modified original post written by Dr. Jared Hoyle)

Photo taken by Brooke Garcia

Recognize this weed? This time of year, we are beginning to see a lot of star-of-bethlehem popping up in lawns throughout Manhattan, KS. In my neighborhood, which is one of the oldest areas in Manhattan, it seems to be in every lawn. We struggle with this particular weed every year in our turf, as well as our landscape beds.

Photo taken by Brooke Garcia

It is a very pretty plant with showy, 6-petaled white flowers that have a distinct green stripe underneath. It is a perennial bulb that sometime appears to look like clumps of grass. It can be hard to spot in a freshly-fertilized, green lawn. The green hues blend together. The leaves are linear and smooth, flat in cross-section and have a with midrib.

This plant likes shady and moist areas of the lawn, but I have also seen it grow in the sunniest locations of my lawn too. With the recent moisture and more on the way we are not short of moist areas in the lawn around Manhattan right now.

Although it is has very distinctive characteristics it can be confused with other plants that are commonly found in lawns; crowpoison (Nothoscordum bivalve),spring beauty (Claytonia virginica), wild garlic (Allium vineale) and wild onion (Allium canadense).

If you do not have a lot of this weed in your turf or landscape beds, it can be effective to hand-dig the plant and bulb completely out of the affected area. However, the leaves tear quite easily. Thus, it can be difficult to completely eradicate the entire plant using the hand-removal method.

For chemical control there are couple of options.  Both sulfentrazone and carfentrazone have shown to be very effective.

For additional information about Star of Bethlehem, see the recent post written by Ward Upham:

Wild Onion, Wild Garlic, and Star-of-Bethleham

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Thank you and best wishes to Dr. Hoyle!

The K-State Turf Team would like to give a heartfelt farewell, thank you, and best wishes to our friend and colleague Dr. Jared Hoyle.

As you saw in Jared’s recent message, he is leaving KSU to join Corteva Agriscience. We will miss Jared, but we are excited for him to pursue other opportunities. We are glad he’ll still be based in Manhattan, at least for now.

Jared joined KSU as an Assistant Professor and Extension Specialist in 2013. He was recently promoted to Associate Professor with tenure. He’s had an extremely productive academic record in both research and extension. Jared has been particularly active in social media, with more than 2,300 followers on Twitter and around 200 blog posts. He has created videos for KSRE, KSUTurf YouTube and other channels with more than 2,700 views. Jared has developed “flipped classroom” online resources to support the Extension Master Gardener Program. Jared also served a critical role as Director of the Rocky Ford Turfgrass Research Center in Manhattan. We will miss Jared as a KSU colleague, but we look forward to working with him in new ways.

Cheers and best wishes to Dr. Hoyle!

Sincerely,

The KSU Turf Team

Megan Kennelly, Jack Fry, Steve Keeley, Dale Bremer, Christy Dipman

Turf research and extension update – KSU COVID19 implications

Hello everyone,

It is an unprecedented time at KSU. We are under highly limited on-campus operations due to the COVID-19 pandemic.

At present, only “mission critical/essential” functions are occurring on campus. Faculty, staff, and students are primarily teleworking from home. Courses have shifted to online-only, extension includes no face-to-face interactions until at least mid-May, and many research labs are essentially closed or running at very minimal levels. However, the KSU Turf Team is still here to support the industry as best we can while carefully following all the public health policies and guidelines.

Currently, much of our long-term turfgrass research is still operational at Manhattan (Rocky Ford Turfgrass Research Center), Olathe (K-State Olathe Horticulture Research & Extension Center), and Haysville (JC Pair Center) but under highly restricted conditions. We have developed Continuation of Operations Plans to work safely following all CDC guidelines and policies of our College of Agriculture and KSU. We have reduced time on-site to essential tasks only. The KSU Plant Disease Diagnostic lab is still open, but with some changes. Details can be found here.

The situation evolved very rapidly over the past 2 weeks, it is still evolving,  and things could change.

In addition, our colleague Dr. Jared Hoyle is leaving KSU to take an exciting opportunity in industry. You can read Jared’s farewell here and our turf team message here. This is additional change for the Turf Team to navigate right now. We are in conversation with college leadership about this topic as well.

In the meantime you can reach us by email and phone.

As always, your local K-State Research and Extension Agent is a best first contact. You can click on this map to find your local office. Agents are also primarily teleworking due to the COVID19 situation but they are responding to email and phone.

Jack Fry: jfry@ksu.edu, turf management questions from professionals.  913-353-6823 (cell)

Megan Kennelly: kennelly@ksu.edu, plant diseases. 785-532-1387

Raymond Cloyd: rcloyd@ksu.edu, insects 785-532-4750

Stay well and best wishes for good health to you and your families. We know many of you are affected both personally and professionally by the current situation. Our top concern is everyone’s health and well-being. Take care everyone.

Plant diagnostic lab open during KSU limited operations due to COVID19

(Megan Kennelly, KSU Plant Pathology, kennelly@ksu.edu)

Hello everyone,

It is an unprecedented time at KSU. We are under limited on-campus operations due to the COVID-19 pandemic.

At present, only “mission critical/essential” functions are occurring on campus. Faculty, staff, and students are primarily teleworking from home. All teaching has converted to online, and research operations have ramped down significantly. Mail and package delivery systems have changed.

Our plant diagnostic lab remains open. I will continue to work closely with Judy O’Mara on horticulture sector samples. Judy, as Director of the lab, provides this important update:

The KSU Plant Disease Diagnostic Lab continues to remain open at this time. However, we are working under limited operations and staff, so turn around may take a little longer than usual.  There have been a few changes to our submission procedures. Please read the information below:

  • No in-person sample delivery to lab. Instead, if you are in Manhattan please use the soil drop box located on the Northwest side of Throckmorton PSC.
  • US Postal Service sample delivery to 4032 Throckmorton PSC 1712 Claflin Rd Manhattan, KS 66506 is still available, but will be checked at a minimum of twice a week. Time sensitive samples  should NOT use USPS and instead use the new temporary address below for UPS/FEDEX.
  • The best mailing option for samples to the plant disease diagnostic lab is BELOW.

Please email us the tracking # so we know that a sample is coming to the lab.

Our NEW TEMPORARY MAILING ADDRESS for UPS/FEDEX packages

KSU Plant Disease Diagnostic Lab
1310A Westloop Pl #351

Manhattan, KS 66502

The growing season is about to kick off and we want to support Kansas growers and county extension offices. If you have questions, please contact us at clinic@ksu.edu

Judy O’Mara

Extension Plant Pathology, State Leader

K-State Plant Disease Diagnostic Lab, Director

jomara@ksu.edu

 

Hoyle to join Corteva on March 30, 2020

After a productive seven years that provided a foundational learning experience not only for my personal growth but also professional growth, I will be joining Corteva Agriscience on March 30, 2020, as a Turf and Ornamental Territory Manager serving Colorado, North Dakota, South Dakota, Nebraska, Missouri and most importantly continuing to serve the great state of Kansas. This decision was not taken lightly given the high quality and professional expectations of the faculty, staff, and students at Kansas State University and additionally the continued commitment to the advancement of the turf industry by the incredibly talented and supportive professionals in Kansas. The current and future professional opportunities at Corteva are ones that my young growing family could not decline. Along with the professional factors, this opportunity provides my wife, daughter and me the ability to continue to grow in Manhattan with the increased flexibility as to where we live in the future. Interim Department Head, Dr. Steve Keeley, is currently working with upper administration in addition to the KSU Turf Team to ensure that the responsibilities associated with my position as Associate Professor as well as my responsibilities as the Rocky Ford Turfgrass Research Center Director be delegated to the appropriate party and peoples. I cannot reiterate enough how appreciative I am to everything Kansas State University has provided me through the years. From tenure and promotion to Associate Professor to an open and welcoming environment to improve my leadership skills and finally but most importantly by providing a “second family” as I began my career and family thousands of miles away from my immediate family. I believe that specific openness and welcoming support of the turf industry in Kansas and surrounding states will help continue the success of the Kansas State University’s turf program. Thank you for the last seven years! I will always be grateful for the memories made at Kansas State University.

-Jared Hoyle, Associate Professor, jahoyle@ksu.edu