Tennessee Turfgrass - April / May 2008

The Official Publication of the Tennessee Turfgrass Association, the Tennessee Valley Sports Turf Managers Association and the Tennessee Golf Course Superintendents Association

The Official Publication of the Tennessee Turfgrass Association, Tennessee Valley Sports Turf Managers Association and the Tennessee Golf Course Superintendents Association

TA B L E O F C O N T E N T S APRIL/MAY 2008

10 Cover Story

F E AT U R E D A RT I C L E S

10 16

Cover Story — Managing Brown Patch in Tall-Fescue Lawns

22 30

Turf Talk — Tools for Turfgrass Irrigation Water Management

Applied Research — Answers to Common Questions about Plant Growth Regulators

22

Turf Talk

30

Landscape

In the Landscape — Hooked on Hydrangeas…

Old-Fashioned Favorites, Now with New Features

D E PA RT M E N T S

4

From the TTA President, Bob Hogan

6

Message from the TVSTMA, Stephen Callis

8

Calendar of Events

34

Index of Advertisers

34

TENNESSEE TURFGRASS

APRIL/MAY 2008

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FROM THE PRESIDENT Bob Hogan

An Update from TTA’s Spring Board Meeting pring is here, and do you know how I know it?

Because we have just had our spring TTA Board Meeting, and we also set our clocks forward. To some of you, both would be a loss of time. But for us on the TTA board, it was “long” time well spent. We have a great board of directors. We have established a great group of committees.

We have mapped our fields, and we are ready to work ground.

We started our meeting by looking at the past. It seems strange to start by looking back, after what I said at the end of my last letter, but it was the right thing to do. The back I'm referring to is our 2008 Conference and Trade Show. We agreed it was one of the best, but there were concerns to address. Looking at the education portion of the conference, room size and signage brought the most attention. I believe we have answers for these concerns. There were minor issues about the speakers' subject matter, their presentations being too short and too long, backup speakers and related topics. These too have been addressed with good solutions. For example, we may reduce the numbers of speakers for the sports-turf sessions but make each presentation longer. Signage will be seen. We may even bring in Lazy-Boy recliners for each section, just to name a few.

Looking at the Trade Show, we had no complaints except to tune our engines, rev our motors and make it even better. Make sure you set your calendars for January 11-13, 2009, for next year's Conference and Trade Show to see the changes.

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TENNESSEE TURFGRASS

APRIL/MAY 2008

Analyzing our financial statement, we are in a good financial position. Profits made from our Conference and Trade Show once again put us in the position to give to education, research and scholarships for our state. Thanks, Jim Uden, for keeping a close eye on our books. If you have any questions about our financial position, please give Cory Blair (our secretary/treasurer) or me a call. Just a reminder — we do have scholarships to give away.

Will you help us spend these funds?

For the past several years, the TVSTMA has contributed to the TTA $3,000 per year to support the cost of our TTA magazine. The magazine is now supporting itself. We voted to discontinue this payment. Look for the changes on the front cover.

In closing, I told the board that the TTA was like a vehicle traveling down the road alongside other professional turfgrass organizations. We should encourage everyone involved in our industry to get on board and become part of TTA. We have something great to offer. We offer to our members a means to become better individuals, more professional and highly educated in the turfgrass industry. This year, we are going to invite everyone in the turfgrass industry to travel our road. Please help us get the word out. I promise that the board of directors will do our part.

Bob Hogan TTA President

Email TTA at: tnturfgrassassn@aol.com

The Official Publication of the Tennessee Turfgrass Association and the Tennessee Valley Sports Turf Managers Association

Tennessee Turfgrass is the official publication of The Tennessee Turfgrass Association 400 Franklin Road Franklin, Tennessee 37069 (615) 591-8286 tnturfgrassassn@aol.com Published by Leading Edge Communications, LLC 206 Bridge Street Franklin, Tennessee 37064 (615) 790-3718 Fax (615) 794-4524 Email:info@leadingedgecommunications.com Editor Mr. Bobby Stringer TTA OFFICERS President Bob Hogan The Hogan Company (888) 224-6426 Vice President Bobby Stringer Germantown Country Club (901) 754-7755 Secretary/Treasurer Cory Blair Rarity Bay Golf & CC (423) 884-3007 Past President Bill Francis The Ridges Golf & CC (423) 913-2276 Executive Secretary Mr. Jim Uden (615) 591-8286 TTA 2008 BOARD OF DIRECTORS Mr. Paul Carter Ms. Shelia Finney Mr. Bill Marbet Mr. Bob McCurdy Mr. Scott McNeer Mr. Tommy Mittlesteadt Mr. Scott Morgan Mr. Mitch Parker Mr. Scott Severance Mr. Robert Stroud Mr. Jay Willis TTA ADVISORY MEMBERS OF THE BOARD Mr. Bill Blackburn Dr. J. Scott McElroy Mr. Lynn Ray Dr. Tom Samples Dr. Dennis Shepard Dr. John Sorochan

FROM THE TVSTMA Stephen Callis

To Grow, We Need Each Other to Serve ello, TVSTMA members. As I write this message, it is snowing outside. By the time you read this message, hopefully it is sunny and warmer, with warm-season grasses beginning to green up.

The weather is just one of many challenges that turf managers face every single day. Luckily, you have an organization that gives you the opportunity to discuss those challenges with other turf managers or vendors who can give you the advice you need.

With that said, we want to make sure that the TVSTMA continues to grow and improve to serve the members. To do so, we need members to help serve the organization in different capacities. For instance, we need members to give their input on what topics or presentations they would like to see at meetings.

We want the TVSTMA to serve its members, and we need the membership to tell us how to serve. You can email me with any comments (good or bad) at stephen@thehogancompany.us, or call me at my office at 888-224-6426.

Depending on when you receive this issue, we have either had our first meeting of the year in Jackson, or it is approaching in the coming days. It will be an excellent meeting, and I hope that everyone, especially those in West Tennessee, are able to attend.

The next TVSTMA meeting will be June 5, 2008, in Knoxville at The University of Tennessee. Bobby Campbell has been gracious enough to host us, and we are planning to have an informative meeting with the staff and researchers from The University of Tennessee.

Thank you for your attention in reading this, and I hope to see you at our next meeting.

H

Stephen Callis TVSTMA President

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TENNESSEE TURFGRASS

APRIL/MAY 2008

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The Tennessee Turfgrass Association serves its members in the industry through education, promotion and representation.

The statements and opinions expressed herein are those of the individual authors and do not necessarily represent the views of the association, its staff, or its board of directors, Tennessee Turfgrass Magazine, or its editors.

Likewise, the appearance of advertisers, or Turfgrass Association members, does not constitute an endorsement of the products or services featured in this, past or subsequent issues of this quarterly publication.

Copyright Š2008 by the Tennessee Turfgrass Association. Tennessee Turfgrass is published bi-monthly. Subscriptions are complimentary to members of the Tennessee Turfgrass Association. POSTMASTER: Send change of address notification to Tennessee Turfgrass Association, 400 Franklin Road, Franklin, TN 37069. Postage guaranteed.

Third-class postage is paid at Franklin, TN. Printed in the U.S.A. Reprints and Submissions: Tennessee Turfgrass allows reprinting of material.

Permission requests should be directed to the Tennessee Turfgrass Association. We are not responsible for unsolicited freelance manuscripts and photographs. Contact the managing editor for contribution information.

Advertising: For display and classified advertising rates and insertions, please contact Leading Edge Communications, LLC, 206 Bridge Street, Franklin, TN 37064, (615) 7903718, Fax (615) 794-4524.

COVER STORY

Managing Brown Patch Disease in Tall-Fescue Lawns

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TENNESSEE TURFGRASS

APRIL/MAY 2008

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CONTINUED

By Alan Windham, Ph.D., Entomology & Plant Pathology Department, University of Tennessee Extension

ith brown patch weather due to arrive in a couple of months, below are answers to 13 frequently asked questions about brown patch — the most common disease in tall-fescue lawns — as well as sound management strategies to common customer complaints. Lawncare contractors, landscapers and grounds-management professionals can share these solutions to keep clients happy.

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1. “I had a beautiful tall-fescue lawn last fall and this spring, but by mid-summer it looked terrible.

What is causing this disaster?”

The most common disease of tall fescue in the Upper South is a fungal disease called brown patch, which causes circular patches of brown grass from 6" to 3' in diameter (Photo 1). As these patches become more

numerous and increase in size, large areas of turf may die.

2. “How do I identify brown patch?”

It’s really pretty simple. Go out early in the morning while the dew is still on the leaf blades. Look for cobweblike strands of fungus growing from the leaf blades of infected grass.

Patches of diseased turf often have what is called a “smoke ring” of fungal growth at the margin of the patch (Photo 2).

Also, look for large lesions on the blades of grass. These lesions are bluish-gray when the disease is active, and they are bleached when weather conditions are not favorable for disease development.

3. “What causes brown patch? Was my lawn seed contaminated?”

Brown patch is caused by a fungus called Rhizoctonia solani, which is commonly found in nearly all soils and does not occur on turf seed.

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COVER STORY Photo 1. Severe brown patch (Rhizoctonia solani) affecting a tall-fescue lawn in June. Photo credit courtesy of A. Windham.

4. “What environmental conditions favor brown patch?”

Hot, humid weather is ideal for the development of brown patch, which often develops when temperatures approach 90º F during the day and 70º F at night. Generally, late May to July is prime brown-patch season in Middle Tennessee. Cooler temperatures and low humidity stop the disease temporarily.

5. “How does shade influence brown patch?”

Common sense tells us that grass growing in shade is slower to dry each morning and thus has more brown patch. Right? Well, this is one time when common sense is wrong. Brown-patch development has more to do with turf density. In general, since there are more tall-fescue shoots per square foot in full sun, you are more likely to have severe brown patch in full-sun turf areas than in shade. Conditions within the turf canopy are simply more favorable for disease development in full sun.

Photo 2. Smoke ring (mycelium) of Rhizoctonia visible at discolored patch edge. Photo credit courtesy of A. Windham.

6. “How does mowing height affect brown patch?”

Research tells us that brown patch is less severe at lower mowing heights. Does this mean that we should be growing tall fescue at 1"? No! Although lower mowing does reduce brown patch, it is not really practical or healthy for turf. You would have to shorten your mowing frequency (to two to three times per week) to prevent scalping. Also, shoot height is directly proportional to root growth. A tall-fescue lawn mowed at 3" will have a deeper root system than a lawn mowed at 1".

7. “Does irrigation affect brown-patch development?”

Watering frequently at night increases the risk of brown patch.

Lawns should be irrigated infrequently and only to a depth of 6".

Irrigation during the day is preferred to irrigation at night.

Photo 3. Untreated tall fescue (left) and healthy fescue treated with azoxystrobin (i.e., Heritage®, right) at a 28-day interval at the UT Plant Sciences Farm. Photo credit courtesy of A. Windham and J. Parham.

8. “Does fertilization timing affect brown patch?”

Absolutely! Fertilization in late spring and summer almost guarantees that brown patch will be a problem. If you intend to fertilize your tall-fescue lawn only once a year, do it in October.

If you must fertilize your lawn more than once, try to complete these activities by October and early spring. Avoid fertilizing your lawn after April 15.

9. “Why is fall seeding preferred to spring seeding for coolseason grasses?”

Fall seeding is preferred for several reasons. First, seeding in the fall allows for two seasons of rapid growth prior to the heat and drought stress of summer. Also, fall seeding allows tallfescue seedlings to mature and survive a moderate amount of brown patch.

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TENNESSEE TURFGRASS

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CONTINUED 10. “Are fungicides available that will help control brown patch?”

Yes. Myclobutanil (Immunox®) or propiconazole (Banner MAXX®) applied as a foliar spray prior to hot, humid weather can prevent brown-patch development. Granular fungicides should be applied with a rotary spreader when the turf is wet.

Generally, though, foliar sprays are more efficacious than granular fungicides.

Results with fungicides are not as satisfactory if the disease has already caused significant damage. Most fungicides must be applied at 14-day intervals when conditions favor disease development. Fungicides such as azoxystrobin (Heritage®) have longer use intervals, up to 28 days of protection (Photo 3).

11. “If I don’t want to apply fungicides, what options do I have to speed the recovery of my lawn?”

Save your money on fungicide applications, and buy turf-type tall-fescue seed instead. Simply overseed your damaged lawn in early fall, and fertilize according to soil-test recommendations.

The amount of recovery is often amazing.

12. “Are any turf-type tall-fescue cultivars highly resistant to brown patch?”

No, researchers are looking for cultivars that are resistance to brown patch. I would stay away from the ultradwarf cultivars, as they are slower to recover from brown-patch damage.

Choose a good turf-type cultivar or a mixture of several cultivars.

13. “Why do I have brown patch in my lawn when I have a lawn service? My neighbor cares for his own lawn and doesn’t have problems with this disease.”

Unfortunately, brown patch is a disease found in wellmaintained turf areas. Brown patch is generally found attacking pure stands of tall fescue, basically a monoculture of one tallfescue cultivar. Your neighbor probably has a mixture of tall fescue, bermudagrass, summer annual weeds such as crabgrass and goose grass, and broadleaf weeds. Also, soil fertility plays a role in brown-patch development.

TENNESSEE TURFGRASS ASSOCIATION • TENNESSEE VALLEY SPORTS TURF MANAGERS ASSOCIATION

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AN EP W P LSI EFDR OR ME S TE HA ER CTHT A

Answers to Common PGR Questions

By Dennis Shepard, Ph.D., Syngenta Technical Support

P

lant growth regulators (PGRs) influence plant growth and development by affecting one or more plant hormones that play a role in cell elongation, cell division or ethylene production. Key changes in turf growth from PGR applications include reduced vertical growth, increased lateral growth, increased turf density, darker green color, increased rooting and fewer and shorter seedheads.

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CONTINUED PGRs are different from fungicides, herbicides and insecticides, which are applied at a certain rate and time to control diseases, weeds or insects, and they generally do not change turf growth and development. PGRs change the turf itself, and results can be influenced by which PGR product is used, turf species and cultivar, the environment and turf-management cultural practices.

The PGRs now used on high-quality turf are trinexapacethyl (TE), paclobutrazol (PA), flurprimidol (FL), mefluidide (ME) and ethephon (E) (see Table 1).

Considerable research with these products has been conducted over the past 20 years, and results have been published in scientific journals, university research reports and trade publications.

For answers to questions about PGRs, turf managers can contact their state university turf-research specialist or the company that makes the product. An excellent source for information on all types of turf research is the Turfgrass Information File at Michigan State University.

This library has been developed over the past several years and is a database that catalogs turf information. There is a small fee to join the TGIF service, but it is well worth it to have access to the latest turfgrass information.

What are the main uses of PGRs? PGRs can be used on most turf areas, including golf courses, sports fields and residential and commercial lawns. The majority of usage is on golf courses where superintendents apply them for several reasons, such as: • To slow turf growth and reduce clippings • To reduce scalping, and improve turf quality and playability • To reduce equipment wear, and improve equipment performance • To reduce mowing, accompanied by significant fuel savings • To increase safety and reduce hand-trimming in hard-to-mow areas • To increase putting speed and/or help with consistent speed throughout the day • To maintain or reduce Poa annua • To suppress Poa annua seedheads • To improve turf stress tolerance from repeat PGR applications • To improve seed establishment and to speed the development of sprigs and sod • To reallocate labor for jobs other than mowing No single PGR will provide all of the benefits listed above, as each has its unique strengths. Determine what

you hope to accomplish with a PGR, and then discuss with the various companies on how to best use their product.

What is the best strategy to suppress Poa annua seedheads in bentgrass?

Mefluidide used alone or the combination of TE + E are the main PGRs used for Poa annua seedhead suppression in bentgrass/Poa annua turf. Application timing is the key challenge because seedheads appear at different times from year to year due to varying environmental conditions.

In the Midwest and northeast U.S., many superintendents use a growing degree day (GDD) model to predict when seedheads will begin to appear. As you go farther south, the GDD model works less well, due to wide temperature swings in the winter and early spring. A good tip for application timing is to watch for Poa annua seedheads in the rough, which is often the first place they appear on a golf course. Then make the PGR application to the greens and fairways.

Can PGRs be tank-mixed with other products?

The short answer is yes, but you need to be careful.

Superintendents often apply several different products together, with the assumption that the products will work the same in a tank-mix as they would if each product was applied separately. They assume that if there is no product settling out or that if no clumps develop in the tank, then the products will work okay. These assumptions can be risky.

The mixing sequence for different products and formulations is normally given on the label. Test each tank-mix combination on a small area, and evaluate for a few days. This may not always be practical, but it is important because turf may respond differently to the same tank mix applied at different times of the year. This is especially true for cool-season turf growing in high temperatures.

You should record the product amount used and the mixing sequence of each application. This is one of the first pieces of information that chemical manufacturers will ask for if you encounter problems due to incompatibility, non-performance or phytotoxicity.

Why do PGR rates vary during the year?

A general guideline is to apply PGRs only to healthy, actively growing turf. For warm-season turf, the best time to begin applications is early summer, after the turf has fully recovered from dormancy and has been mowed a couple of times. Slight to moderate phytotoxicity

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APPLIED RESEARCH sometimes occurs with the first PGR application of the season, and this can be minimized by adding about 0.10 lbs./1,000 sq. ft. of nitrogen to the spray tank.

As warm-season turf increases in turf density and vigor during the season, it may take a slightly higher rate of the PGR to maintain growth suppression. Most PGR applications on warm-season fairways are done on a 21-day to 28-day schedule.

On bermudagrass greens, superintendents often apply reduced PGR rates every 7 to 14 days.

While springtime is generally the peak growing period for cool-season turf and is a good time to begin PGR applications, the turf is still tender from winter dormancy, and slight phytotoxicity can occur with the initial application. Adding nitrogen or iron to the tank will minimize discoloration.

As the season progresses and temperatures increase, PGR rates sometimes need to be increased for cool-season turf. One reason is that healthier, denser turf may need slightly higher PGR rates than early in the season. Also, recent research in cool-season turf has shown that the PGR active ingredient may be metabolized more quickly as temperatures increase.

PGR applications to cool-season turf are usually done on a 7-day to 14-day schedule on greens, and on a 21-day to 28-day schedule on fairways. Part of the art of using PGRs is to determine when and how much to apply. Rates can vary during the season as turf responses to the environment and cultural practices change. Use the PGR label as a guideline, and adjust rates as needed during the season.

applied to. Use the listed species rate as a starting point for evaluation, and then adjust the rate to fit your program for specific cultivars.

How do I start a PGR program?

Follow the steps below to begin a PGR program at your site: 1. First decide what benefits you want from the PGR program.

2. Identify your main turfgrass species (and cultivar, if possible).

3. Review the PGR product labels.

4. Talk to the company on how to best use its PGR product.

5. Talk to other superintendents and turf managers in your area who have used PGRs. 6. Talk with state university researchers on their experience and recommendations.

7. Review your current maintenance plan and determine the best PGR product, time of application and rate to give the desired benefits.

8. Test any new product on a small area first.

9. Keep records and take pictures of the turf response.

Benefits like increased density, reduced Poa annua, increased stress tolerance and others will result only after multiple PGR applications. The addition of a PGR to a turfmanagement plan results in an extra expense. However, after evaluating the results, you will find the PGR may pay for itself with savings in other areas like fuel and labor.

Why aren’t all the cultivars listed on a PGR label?

New turfgrass cultivars are continually being developed, and it is difficult to evaluate product response on each new cultivar and then immediately add that information to a label. The product label will list the turf species that the PGR can be

Dennis Shepard has worked with plant growth regulators for 20+ years and currently directs PGR research for Syngenta. He lives in Franklin, TN, and can be reached at dennis.shepard@syngenta.com.

Table 1. Plant growth regulators (PGRs) labeled for use on high-quality turfgrass.

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Common Name

Uptake Site

Mode of Action

Product Name

Company

Trinexapac-ethyl

Foliar

Reduced cell elongation

Primo MAXX™ Governor™

Syngenta The Andersons

Paclobutrazol

Root

Reduced cell elongation

Trimmit® 2SC Turf Enhancer™ TGR™

Syngenta The Andersons The Andersons

Flurprimidol

Root

Reduced cell elongation

Cutless

SePRO Corp.

Mefluidide

Foliar

Reduced cell division

Embark®

PBI Gordon

Ethephon

Foliar

Increased ethylene

Proxy®

Bayer

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T U R F TA L K

Tools for

Turfgrass Irrigation Water Management

By Garry Grabow, Ph.D., PE., Dept. of Biological and Agricultural Engineering, NC State University

A soil-moisture probe being installed in one of the study plots, about 5� below the soil surface.

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CONTINUED

A

rise in installation of residential and commercial irrigation systems, increasing competition for water and water-use restrictions all point to a need to use "smart" irrigation technologies and techniques.

With most buried irrigation systems, irrigation events and durations are controlled with an irrigation-control clock. While these controllers are set to apply a certain amount of water at a certain time, numerous calculations must be done to achieve the correct controller settings. Also, changes must be made as the turf ’s water demand changes. Applying the correct amount of water requires that you understand not only

the water demand of the turf, but also the application rate of the irrigation system. Most homeowners and operators of these systems know neither. To complicate matters, irrigation scheduling (when and how much to water to apply) in humid regions such as Tennessee is difficult due to unpredictable rain events.

Because buried irrigation systems have high investments costs, it is important that these systems are used to maximize their benefit, applying the proper amount of water at the proper time, thereby keeping turf healthy while using no more water than necessary. The dual objectives of conserving water and preserving turf quality suggest that the use of controllers that incorporate “smart” technology holds promise for turf irrigation.

TENNESSEE TURFGRASS ASSOCIATION • TENNESSEE VALLEY SPORTS TURF MANAGERS ASSOCIATION

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TN UE W R FS TFARLOKM T H E T T A controllers base their system upon longterm historical weather data. They may adjust the long-term average ET to current conditions using an on-site temperature sensor. Some systems factor in on-site rainfall, while others consider general rainfall patterns in the area.

Ease of setup and operation of ET controllers range from fairly easy to complex. Depending upon the controller, users may be required to input a variety of information, including: the type of turf or landscape to be irrigated; specifications of the irrigation system, such as sprinkler type or application rate, and application efficiency; and site conditions, such as shading and ground slope.

Using the supplied system and site information and weather data, ET controllers run a “water balance” that keeps track of how much water is in the soil. The basic operation of these controllers is to adjust the run times at each irrigation event, thereby adjusting the amount of water applied to the turf. AnET Dr. Garry Grabow at the shed that houses the “smart” technology systems being evaluated. controller operates most efficiently when On the site are forty 13’ X 13’ fescue plots irrigated with pop-up spray heads. set in an “automatic mode,” in which case the controller itself will select the There are a number of commercially available tools to help appropriate days to water. Users can also enter schedules that with turf and landscape irrigation water management. They can prohibit watering on specific days, such as those associated with be broadly separated into two categories — those that use local watering restrictions.

When selecting one of these systems, it is important to know feedback from a sensor that monitors the amount of moisture in the rootzone and those that use weather data to estimate the the flexibility of the controller, and from where it collects amount of water used by the turf to adjust irrigation. The weather data. In areas of highly localized rainfall, systems that irrigation industry calls these tools “Smart Water-Application collect local rainfall data have an advantage. There are many Technology” or SWAT. These systems are more prevalent in the manufacturers of these systems, which vary in cost depending western United States, and some water utilities in California are upon the number of irrigation zones that can be served, offering vouchers or rebates for customers who purchase programming features and any associated weather sensors.

For systems that use communication systems such as satellites approved SWAT technology. to retrieve weather data, there is also a modest monthly or Weather-based controllers annual fee.

Irrigation controllers based upon weather data, also referred to as “ET” controllers, use weather data to adjust the amount Soil-moisture-based systems of water applied as the turf’s demand for water changes. As Systems based on soil moisture use feedback from sensors the name implies, ET controllers estimate evapotranspiration placed in the soil to adjust watering. In theory, these systems (ET) of the turf. ET is the total amount of water used by integrate the elements of a water balance into one measurement the plant (transpiration) and by evaporation from the soil and — the amount of water in the soil.

The simplest type of soil-moisture-based system is an“addplant canopy.

Most ET controllers collect “real time” weather data and on” system that is added on to a standard irrigation-control update the estimated ET daily or even hourly. The data is clock. Such systems came on the marker about ten years ago. obtained either from local weather stations via phone line or They comprise a soil-moisture sensor and a module with user satellite, or from on-site measurements taken by simple weather interface. In operation, the clock is programmed to irrigate as instruments supplied with the controller. Other variations of ET normal, and the sensor is used to override a scheduled irrigation 24

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CONTINUED

Costs

Most ET controllers range from $300 to $500, depending upon the number of irrigation zones they control, the level of sophistication and on-site weather sensors (if any). The most expensive ET-based systems provide flow monitoring and a software interface and cost up to $4,000.

The cheapest of the “smart technologies” are the add-on soil-moisture-based systems, starting under $200. Soilmoisture-based systems that have their own controller are slightly more expensive and depend upon the number of zones they can control.

The most expensive soil-moisture-based technologies are the “on-demand” systems. The cost depends upon whether or not they are retrofitted to existing systems or installed in a new system. When installed with a new system, all sensors and valves are part of a “two-wire system,” eliminating the need for separate wiring of each zone. When installed in existing irrigation systems, “zone adapters” are required to allow the system to emulate a two-wire system that allows

communication between the sensors and the solenoid valves. These controllers cost about $2,500, not including the zone adapters.

The more-expensive systems are not targeted to homeowners but to commercial turf and landscape irrigation. Reduced pricing is generally available to contractors for all systems.

Recent research

Three “smart” systems are being evaluated at NC State University by the Dept. of Biological and Agricultural Engineering (Drs. Garry Grabow and Rod Huffman) and the Dept. of Crop Science (Drs. Dan Bowman and Grady Miller). A study site with forty 13' X 13' plots sod in tall fescue and irrigated with pop-up spray heads was installed in fall of 2006.

One season’s worth of data has been collected for an ET controller and two soil-moisture-based systems (an add-on system and an “on-demand” system). These systems are being compared to a standard irrigation-control clock set to replace the long-term average irrigation requirement.

Irrigation frequency is also being evaluated in this study. All systems except for the “on-demand” system are set to water daily, twice a week and once a week. Turf quality is being assessed by a visual rating system, and turf-canopy temperatures are being recorded to monitor moisture stress.

Total applied water in inches for the 20-week duration of the study in 2007 is presented in Table 1. These amounts factor in an irrigation system efficiency of 80%, which roughly means that, on average, the net irrigation amount (water received by the turf) was only 80% of the applied amount.

This past summer was hotter and drier than normal, so the net amount of water applied by the timer treatment (long-term average irrigation requirement) was below that required for full irrigation of fescue. The estimated turf water requirement over the course of the 20-week study was 20.9", assuming a crop coefficient of 0.8. The crop coefficient is multiplied by the “reference ET” to estimate the water requirement of a specific

Table 1. Total Applied Water in Inches from April 22 to September 8, 2007 (20 weeks).

Technology

if the soil is too wet. This “too wet” setpoint level may be adjusted by the user.

Some systems use a somewhat arbitrary scale of wetness (e.g., 1–10), while others let the user specify a soil-moisture level by entering a volumetric soil-water content (percent water by volume of soil), above which any pre-scheduled irrigations will be disabled. To determine the setpoint of these systems, the soil is saturated (e.g., by a garden hose or sprinkler) and then allowed to drain for a period of time (usually one day for medium- to heavy-textured soil and perhaps 12 hours for a sandy soil). This establishes the “field capacity” of the soil, or the amount of water held by the soil against gravity. The setpoint is normally set to 75% of the water content at field capacity.

Adjustments to the setpoint can be made at any time as required.

Some manufacturers of soil-moisture-based systems also sell units with controllers, rather than just the “add-on” sensor with a module.

In more sophisticated soil-moisture-based systems, “ondemand” irrigation can be achieved. Two levels of soil moisture can be set — a lower setpoint to initiate irrigation and a higher setpoint to terminate irrigation. Soaking cycles (when irrigation is temporarily halted) can be used to allow the water to reach the sensor so that over-irrigation does not occur. Watering windows can be programmed to allow for constraints such as wateringday restrictions.

“On-demand” systems are complete systems, unlike the addon systems, and may have a number of added features. These include system monitoring of flow rates and electrical-current usage to warn of any potential irrigation system problems. They can also add multiple moisture sensors that can be assigned to control any zone(s) the user specifies. Software interfaces and remote communication options are available with these more sophisticated systems.

Timer1 Add-On2 On-Demand3 ET4

Irrigation Frequency, days per week 1 2 7 16.88” 16.92” 15.62” 8.56” 12.81” 13.87” 17.64” 16.27” 24.54” 25.66”

Standard irrigation control clock set to replace long-term average irrigation requirement with added rain sensor.

2 “One-setpoint” add-on system with soil-moisture sensor and module added to standard timer.

3 “Two-setpoint” on-demand stand-alone system with soil-moisture sensor.

4 ET controller with rain sensor added.

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TENNESSEE TURFGRASS ASSOCIATION • TENNESSEE VALLEY SPORTS TURF MANAGERS ASSOCIATION

25

T U R F TA L K “crop,” in this case tall fescue. A crop coefficient value of 0.8 is commonly used for a cool-season turf such as fescue.

The reference ET was estimated using the Penman-Monteith equation and weather data collected on-site. Although 11.4" of rain fell during the 20-week study period, less than half that amount was usable, since much of the rain came in unevenly distributed intense thunderstorms, and only a portion was stored in the root zone.

The last half of June and the first half of July were particularly hot and dry, so the plots irrigated by the standard irrigation-control clock and by the soil-moisture system added to a standard control clock did not receive the amount of water the plots demanded. Turf quality was best for plots irrigated with the “on-demand” system and the ET controller system. The “on-demand” system provided the best combination of efficient irrigation and turf quality, and this was the most expensive system tested.

While the plots irrigated by the ET controller at twice-a-week and daily intervals had high turf quality, more water was applied than the “on-demand” system that provided equal turf quality. In general, plots watered only once a week had poorer turf quality than those watered twice a week or daily.

The study is planned to continue for two more years so that longer-term trends in performance can be assessed.

Conclusions

“Smart” irrigation technologies hold promise for efficient irrigation, thereby conserving water while maintaining healthy turf. However, these systems are not a “magic bullet,” and setup and adjustments by a landscape professional may be required, especially for the weather-based (ET) controllers. Setup, monitoring and adjustment are especially important if the dual goals of water conservation and acceptable turf quality are to be met.

Reducing water application through the use of these technologies may expose poorly designed irrigation systems (poor uniformity), and these “smart” systems will not solve problems due to poor irrigation-system design.

One easy, effective and inexpensive way of reducing water used by turf and landscape irrigation is to install a rain sensor.

In regions of high rainfall, this can result in substantial water savings by simply preventing irrigation during or immediately after a rain.

IN THE LANDSCAPE

Hooked on Hydrangeas…

Old-Fashioned Favorites, Now with New Features

‘Endless Summer®’ (center, just to the right of the path) flowers on the current year’s growth.

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CONTINUED Photos courtesy of Sandy Reed, Ph.D.

I

n today’s gardening world, hydrangeas are one of the hottest commodities. Go to any newsstand, and pick up all the gardening and home-improvement magazines. What do you see as you look through the articles and advertisements?

Hydrangeas, hydrangeas, hydrangeas!

While all the cultivated species of Hydrangea have grown in popularity during the past decade, the queen of the genus is still the bigleaf hydrangea (Hydrangea macrophylla ssp. macrophylla). Grown both as landscape and florist plants, the size and color spectrum of bigleaf-hydrangea flowerheads provide unparalleled visual appeal.

The upswing in the popularity of this oldfashioned favorite is due, in part, to the many new and improved cultivars that have recently become available in the U.S. market. Several cultivars have been available in Europe or Japan for many years, but they have only recently been imported to this country.

Listed on the next few pages is information on some of the exciting new cultivars of bigleaf hydrangea.

Remontant cultivars The biggest breakthrough in bigleaf-hydrangea breeding is the discovery of plants that flower on current year’s growth. Most members of this species flower on last year’s wood, making them very susceptible to winter injury and late-spring freezes.

Since Tennessee is in the transition zone — an area of the country where wildly fluctuating fall and spring temperatures are the bane of landscapers and gardeners — most bigleaf hydrangeas do not flower reliably here.

New cultivars that flower on current year’s growth have been termed remontant, which indicates that they may flower more than once during a season. The first of these cultivars to reach the marketplace was ‘Endless Summer®’ (‘Bailmer’). ‘Penny Mac’, ‘Oak Hill’, ‘Decatur Blue’ and ‘David Ramsey’ soon followed. While not as widely available as ‘Endless

IN THE LANDSCAPE Summer’, these four cultivars are very similar in appearance and performance to ‘Endless Summer’. ‘Forever and Ever’ and ‘Blushing Bride’ (a white-flowered form) are also remontant but have only just become available during the past year.

Breeding programs at the U.S. National Arboretum and the University of Georgia are currently focused on developing new remontant cultivars that exhibit disease resistance and a wide range of ornamental traits. Accordingly, the selection of hydrangeas that flower reliably should expand dramatically in the next few years.

Unusual flower colors and forms Flower color in most bigleaf hydrangeas is dependent on soil pH. Under acidic soil conditions, where aluminum is available, flowers will be blue. As the soil pH increases, aluminum availability drops and flowers become pink. A few cultivars lack the ability to produce blue flowers under acidic soil conditions and instead will become purple or a muddy red color. A few white-flowered cultivars are also available.

Intensity of flower color, whether blue or pink, varies by cultivar. Perhaps the most intensely colored cultivar is ‘Brunette’. When grown under high soil pH conditions, mophead flowerheads of a very deep red are produced; in acidic soil, they become violet blue to purple.

Several of the Teller series cultivars (‘Blaumeise’, ‘Fasan’, ‘Kardinal’, ‘Nachtigall’, ‘Taube’ and ‘Zaunkoenig’) also have extremely deep-colored flowers. These cultivars, which were bred in Switzerland, are noted for their large lacecap-type flowerheads; unfortunately, most are tender and need protection to flower in Tennessee.

While most bigleaf-hydrangea flowers are a uniform color, a few cultivars that have white or light-colored margins on blue or pink sepals (picotee pattern) are available. Among these are ‘Harlequin’, ‘Button ‘n Bows®’ and the Frau series (Halo Hydrangeas™).

Several double-flowered forms of bigleaf hydrangea — including ‘Fuji Waterfall’, ‘Hanabi’, ‘Izu-no-Hana’, ‘Jogosaki’ and ‘Shamrock’ — have recently been introduced. While most of these cultivars have lacecap flowerheads, ‘Fuji Waterfall’ has more of a loosely formed mophead inflorescence.

While delicate in appearance, when planted in the foreground of a landscape where they can be viewed up-close, double-flowered forms of the mountain hydrangea (H. macrophylla ssp. serrata or H. serrata) are stunning. Some double-flowered mountain hydrangea cultivars to consider are ‘Chiri-san Sue’, ‘Komachi’, ‘Miyama-yae-Murasaki’ (‘Purple Tiers’) and ‘Shichidanka’.

On the opposite end of the spectrum from the delicate mountain hydrangeas is the bigleaf hydrangea ‘Big Daddy®’.

With mophead flowerheads that can exceed a foot in diameter, ‘Big Daddy’ stands out in the landscape.

Clockwise, from top left:

‘Chiri-san Sue’ is a double-flowered mountain hydrangea cultivar.

Bred in Switzerland, ‘Fasan’ is noted for its large, deeply colored lacecap flowers.

The golden-yellow foliage of ‘Lemon Zest’ contrasts nicely with darker landscape plants.

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Foliage color Cultivars of bigleaf hydrangea with variegated foliage have been available for some time, but landscapers should still keep them in mind. All of the variegated cultivars produce lacecap inflorescences, and most flower poorly. However, these plants are grown for their foliage, not their flowers — when planted in a shaded area, they brighten up the landscape.

‘Mariesii Variegata’ and ‘Maculata’, both of which produce green leaves with

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white margins, are the most commonly available variegated cultivars. More interesting forms include ‘Tricolor’ (deep green, light green and cream), ‘Quadricolor’ (deep green, light green, cream and yellow) and ‘Lemon Wave’ (bright yellow splotches on green and white leaves).

Another hydrangea that can be used to brighten the landscape is ‘Lemon Zest’. A mophead form that usually produces pink flowers, ‘Lemon Zest’ has golden-yellow foliage that really “pops” when planted near plants with dark-green foliage.

For more information on hydrangeas, contact Dr. Sandy Reed at sreed@blomand.net.

I N D E X O F A DV E RT I S E R S

CA L E N DA R O F E V E N T S

Bayer www.bayerprocentral.com ....................................................9

April 30

TVSTMA West Tennessee Field Day Location: West Tennessee Healthcare Sportsplex, Jackson, TN

May 13

MTGSA Meeting Location: Temple HIlls C.C. (Meeting & Golf)

BWI Companies www.bwicompanies.com ................................7, 27 Covermaster, Inc. www.covermaster.com ......................................27

May 13

ETGCSA Meeting Location: Baileyton G.C., Bailyton, TN

Dickens Turf & Landscape Supply www.dickenssupply.com ............5

May 19

MAGCSA Meeting Location: Meadowbrook C.C.

E & S Soil and Peat www.eandssoil.com ......................................19

June 5

TVSTMA Upper East Tennessee Field Day Location: University of Tennessee, Knoxville, TN

June 9

TNLA/HRI Golf Tournament (TN Nursery & Landscape Assn.)

Location: Forrest Crossing Golf Course, Franklin, TN

Ewing www.ewing1.com ......................................Inside Front Cover Greenville Turf & Tractor, Inc. www.JohnDeere.com ........................3 Harrell’s Custom Fertilizer www.harrells.com ................................21

June 10

ETGCSA Meeting Location: Toqua G.C., Loudon, TN

Jackson Sand ..............................................................................19

June 10

Tennessee Green Industry Field Day (TN Nursery & Landscape Assn.)

Location: Williamson County Ag Expo Center, Franklin, TN

June 10

MAGCSA Meeting Location: Germantown C.C.

June 19–21

Outdoor Power & Equipment Institute 56th Annual Meeting Location: Henderson, NV

July 14

MTGSA Meeting Location: Old Fort G.C. (Golf Day & Tournament)

John Deere Landscapes www.johndeerelandscapes.com ..............13 K-Rain Manufacturing Corp. www.krain.com ................................15 Keeling Company www.keelingcompany.com ................................14 Kesmac, Inc. www.kesmac.com ..................................................29

July 15

ETGCSA Meeting Location: Springbrook C.C., Niota, TN

July 28 – August 1

TPI Summer Convention & Field Days (Turfgrass Producers International) Location: Eagle Lake Turf Farms Calgary, Alberta, CAN

August 5

ETGCSA Meeting Location: Country Club of Bristol, Bristol, TN

August TBA

TVSTMA Lower East Tennessee Field Day Location: McCallie School, Chattanooga, TN

September 8

MTGSA Meeting Location: Graymere C.C. (Expanded Educatioal Meeting & Golf)

Sigma Organics Inc., Nashville, TN www.sigmavalidation.com ........33

September 15

MAGCSA Meeting Location: Spring Creek Ranch

Smith Turf & Irrigation www.smithturf.com ......................Back Cover

September 18

University of Tennessee Field Day Location: Univ. of Tennessee, Knoxville, TN

October 6

ETGCSA Scholarship & Research Tournament Location: Tennessee National, Loudon TN

October 14

MAGCSA Meeting Location: Wyndyke C.C.

September 8

MTGSA Meeting Location: Clarksville C.C. (S&R Tournament) Tentative

November 4

MAGCSA Meeting Location: Chickasaw C.C.

November TBA

TVSTMA Middle Tennessee Field Day Location: to be announced, Nashville, TN

January 11– 13, 2009

43rd Annual TTA Conference & Trade Show Location: Marriott Cool Springs, Franklin, TN

Mid Tenn Turf, Inc. www.midtennturf.com ....................................14 Newlife Turf, Inc. www.newlifeturf.com ........................................19 Pennington Seed, Inc. ............................................Inside Back Cover www.penningtonseed.com ProSource One www.prosourceone.com ......................................19 Sepro www.sepro.com ................................................................20

Southeastern Turf, LLC www.southeasternturf.com ..........................7 Sur-Line Turf, Inc. ........................................................................26 Syngenta Turf & Ornamental ..........................................................9 www.syngentaprofessionalproducts.com The Turfgrass Group ....................................................................33 Turf Mountain Sod, Inc. www.turfmountain.com ............................33 Turf Specialties www.turfspecialties.net ........................................27 Winstead Turf Farms, Inc. www.winsteadturf.com ..........................28

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