Opportunity Knockswith the UltradwarfsSuccess with an ultradwarf might be easier than you think.

by CHRIS HAKIWlGER

Using side-by-side replicated field trials is a great way to compare the differences betweenthe various ultradwarf bermudagrass varieties before making the final selection for yourgolf course.

CHANGE is exciting. Change canbe intimidating. Change may befrustrating. The introduction of

a new generation of bermudagrassvarieties for putting greens, commonlyreferred to as the ultradwarfs, hasevoked some or all of these emotionsat golf courses that have tried them.Golfers at many courses with ultra-dwarf bermudagrass putting greens areenjoying green speed, smoothness, andfirmness that are at an all-time best. Anastonishing number of golf courseshave eradicated their Tifdwarf greensand have converted to an ultradwarf.With these impressive credentials, onemight assume that ultradwarf varietieswould be universally accepted as thechoice for bermudagrass greens. Thatassumption would be dead wrong.

Currently, the phrase "the ultra-dwarfs are not for everyone" is makingthe rounds from turfgrass conferencesto magazine articles to green committeemeetings. This comment and the under-lying tone of negativity is scaringpeople. The phrase might be accurate,but it is devoid of any tangible infor-mation and only serves to frightenand intimidate. It evokes a fear of theunknown.

Given the success of ultradwarfsexperienced by hundreds of courses, itis clear that they deserve strong con-sideration when establishing a ber-mudagrass putting green. This article isintended for those involved in select-ing a new bermudagrass for their golfcourse, and it aims to replace fear withfacts. The reader should have a clearunderstanding of what an ultradwarf is,the performance of the ultra dwarfs inthe field, and the tools necessary tomake an ultradwarf a success.

What is an Ultradwarf?No one knows who coined the term

ultradwarf, but it is a term that hasbecome widely accepted in the turfgrassindustry. Champion, Floradwarf, Mini-Verde, MS-Supreme, and TifEagle arethe ultradwarf varieties commercially

available today. The industry definitionof an ultradwarf today is any varietythat can withstand a mowing height of0.125 inch Cis inch) or lower over anextended period of time.

Numerous turfgrass scientists havestudied the ultradwarfs and haveoffered a more formal definition.Guertal and White described thesevarieties as having shorter leaves thanare found on Tifdwarf and Tifgreen andbeing tolerant of lower mowing heights(Guertal and White, 1998). Gray andWhite have separated the ultra dwarfsinto vertical or horizontal dwarf cate-gories based on vertical and horizontalgrowth rates (Gray and White, 1999).The morphological differences betweenthe ultradwarfs and Tifdwarf have beenreviewed, too (White, 1999; Beard andSifers, 1996). Table 1 provides informa-tion about the physical characteristicsand genetic origin of several ultra-dwarfs. Please note that although thesevarieties are all considered ultradwarfs,they do vary substantially in theirphysical characteristics.

The Ultradwarfs Find a Home

The past few years have seen a majorchange in attitude toward bermuda-grass putting greens. In the traditionalbermudagrass zone of Florida, the deepSouth, and the Southwest, courses re-grassing or rebuilding putting greenshave selected an ultradwarf variety anoverwhelming majority of the time,hoping to take advantage of thepotential for better putting surfaces.The ultradwarfs are having a big impactin the southern portion of the transitionzone, where bentgrass has always beendifficult to grow, too. In the past, manycourses have felt that mediocre orpoor-quality bentgrass produced abetter putting surface than Tifdwarf.

The ultradwarfs are pushing the bent-grass line farther north, with successfulultradwarf putting greens established inNorth Carolina, Tennessee, Arkansas,and throughout the Southwest. Clubsare finding that the management pro-gram associated with the ultradwarfsis easier and less expensive than trying

SEPTEMBER/OCTOBER 2001 1

FasteriSlower

VerticalGrowth Ratevs. Ttfdwarf(Gray andWhite, 1999)

Table 1Physical characteristics and genetic origins of selected ultradwarf varieties.

Multiple. ofThatCh

Lateral AccumulationGrowth Rate vs. TIfdwarl . Percent More Shoots .~,J~(Gray and .. ,' ... (Gray and ~~ per~unit area VS,. Ttfdwarf'

't, White) ~ ;~', i~"; ,.White)' . (Gray'and~White),~, .11 i'l " r

';;:';' 11.7X1;; ,-

GeneticOngin (Beardand Sifers, ."1996) Ie,,, .

Selection fromTtfdwarf green

Selection from Slower Similar , 7.5XTtfgreen

'.il!

:!< ~ ~!.l

Selection from, Slower Faster 5XTIfdwarf

II lIII ~

Selection from Slower FasterTtfgreen green

,<;\ .;f;

~ii

Gamma-induced Slower Similarmutant ofTtfway II

Mini-Verde

'f,"j,

Champion

TtfEagle

. Floradwarf

! MS-Supreme

to maintain bentgrass putting greensthroughout the summer. Fungicidebudgets are down, fans are not needed,and labor requirements have beenreduced at the clubs that convertedfrom bentgrass to an ultradwarf.

Are the U1tradwarfs Measuring Up?To answer this question, it is neces-

sary to examine performance on thegolf course as well as in research trials.The expectations of the ultra dwarfvarieties have been high, success storieshave been abundant, and failures havebeen publicized widely. To date, anoverwhelming majority of golf courseswith an ultra dwarf are pleased withtheir selection and have no regrets fornot selecting Tifdwarf. For the first timeever, reports from South Florida havegolfers complaining about the puttinggreens being too fast! This is amazing,considering the unbelievably high ex-pectations in this region and the frus-tration with Tifdwarf over the years.

In isolated instances, disease, scalp-ing, shade, excess thatch, cold tempera-tures, and management errors haveinjured some of the ultradwarl varieties.Putting quality has been compromisedat these courses and changes in puttinggreen management have been neces-sary to resolve the problems.

A review of research trials yieldssome interesting observations as well.There are numerous sites throughoutthe country where the ultra dwarfs andTifdwarf were planted in replicated

trials. Results have been positive, witha few notable exceptions. At TexasA&M, the ultradwarfs have beenplagued with a myriad of problems(White, 2000). More than one visitorhas left these trials thinking, "Why onearth would someone plant an ultra-dwarf?" At other locations, such asAuburn University and the USGA/GCSAA/NTEP putting green trials, theultradwarfs have been as steady as arock. A wealth of information on thesetrials is available free of charge atwww.ntep.org, and in practically everyvariable measured, Tifdwarf finishesat the bottom of the rankings (NTE~2000).

With a diversity of results in the fieldand in research trials, what conclusionscan be made regarding the performanceof the ultradwarfs? First, it is obviousthat the ultradwarfs are neither perfectnor foolproof. They require appropriatemanagement and good growing con-ditions. Remember that Tifdwarf ishaunted by numerous weaknesses, too.After more than 30 years of researchand experience in the field, it is not toodifficult on any given day to locate aTifdwarf putting green in poor condi-tion. Second, it is clear that we donot understand completely what stressor combination of stress factors leadsto poor performance. Third, puttingquality on an ultra dwarf green withgood management is significantly bet-ter than Tifdwarf or poor-quality bent-grass.

U1tradwarf Management IssuesThe management of the ultradwarf

varieties has been described as requir-ing'more labor and expense. However,this description paints the maintenancerequirements with too broad a brushbecause it does not differentiate man-aging for plant health versus managingfor playability. Each of these manage-ment components will be reviewed.Managing for Plant Health

The management protocol for main-taining healthy, viable ultradwarl greenshas been changing over the last fewyears in response to turfgrass researchand trial and error on the golf course.There are several areas that appear tobe critical to managing the health of anultra dwarf. This section is not a "howto" primer on ultra dwarf management,but it does focus on the areas mostcritical for managing plant health.

Biomass Management: The rapidbuildup of organic biomass in theupper portion of the profile of ultra-dwarf turf is well documented (Guertaland White, 1998; Gray and White,1999; White, 1999; Beard and Sifers,1996). This biomass is primarily a layerof stolons that should be maintained ata depth of 1/4 inch to avoid potentialproblems. Initially researchers hopedthis layer could be managed throughthe traditional Tifdwarf program oflight, frequent vertical mowing, coreaeration, and topdressing, while stillproviding an excellent putting surface.

2 USGA GREEN SECTION RECORD

Failure to cover ultradwarf greens when winter conditions warrant can resultin an unnecessary level of winter injury.

However, results in the field and insome research trials have indicatedthat the physical injury caused by thevertical mowing component of theprogram may increase the chance fordecline problems (White, 2000).

Many superintendents have proven itis possible to maintain the biomasslayer at 1/4 inch in an ultradwarf puttinggreen with brushing instead of verticalmowing. It requires a different methodof management, but not at an extracost. Because many of the ultra dwarfshave very low vertical growth but havean increased lateral growth rate, low-growing stolons can escape the bed-knife and grow to undesirably longlengths. This contributes to the pro-liferation of the stolon or biomasslayer. Vertical mowing severs longstolons once they have developed, butbrushing successfully stands up shorter,more juvenile stolons and clips themoff before they become too long. Brush-ing every five to seven days is much lessinjurious to the plant than verticalmowing ~very seven to 14 days.Brushes are available that fit into thefront roller bracket and can be set ~venwith the bedknife. The beauty of thisapproach is the ability to mow andbrush at the same time without anyextra labor.

Core aeration followed by filling theholes with sand topdressing continuesto be the most effective means tophysically remove the accumulationof organic matter in the upper portionof the profile. The general school ofthought is that no additional coreaeration beyond what is appropriate fora sound Tifdwarf program is needed.

Light sand topdressing is essential formanaging biomass. Light dustings ofsand every seven to 14 days on averagehelp dilute the accumulation of organicmatter, improve air-filled porosity, andproduce a firm surface without incon-veniencing golfers. The rate is so lightthat only an irrigation cycle is neededto incorporate the sand into the canopy.

Some areas have reported difficultyfinding sand topdressing that is easilyincorporated into the canopy. Sandparticle sizes between 0.25 mm and.75 mm are generally advised for thismaterial. Coarse sand particles above.75 mm that remain on the surface candamage mowing reels and can interferewith putting quality. Many sand com-panies have the ability to screen outparticles above .75 mm in topdressingsand if they are advised of this problem.

The long-term impact of using top-dressing sand lacking coarse particles

has been debated. Some feel that itmay contribute to black layer forma-tion (Unruh and Davis, 2001). Becauseblack layer requires anaerobic condi-tions, it is hard to imagine that a well-managed profile, even with a finertopdressing sand, will consistently favorthe development of black layer. Afterall, light and frequent topdressing withany kind of sand is a relatively newphenomenon. There are thousands ofbermudagrass putting greens that weretopdressed once or twice per year thatexhibit no signs of black layer. Theo-retically, the alternating layers of sandand organic matter in these greensshould be havens for black layerdevelopment. In reality, it has nothappened.

Moisture Management: The ultra-dwarfs have outperformed Tifdwarf inareas where water restrictions havenecessitated reduced watering. Theonly moisture management issue thathas arisen is the occasional sealing ofthe surface during periods of rapidgrowth. The surface canopies becomeso tight and dense that water runs offinstead of soaking into the canopy.Localized dry spots and hydrophobicsoil are common when the surfaceseals.

A sealed surface is best dealt with bytaking a proactive approach. The firstrequirement is an irrigation system thatprovides good coverage. Next, handwatering should be practiced on areasprone to drying out or exhibiting poorwater penetration. Also, superinten-dents can use wetting agents, solid-tine

cultivation, and water injection tominimize dry spot problems. Whenmanaged pro actively, moisture man-agement should not be too difficult.

Disease: Reports of diseases such asbermudagrass decline (Gaeumanno-myces graminis var. graminis), cur-vularia (Curvularia species), and springdead spot (Ophiosphaerella herpo-tricha) have appeared in several articles(Unruh, 2001; White, 2000). However,in the broader view, disease outbreaksappear to be isolated, according toUSGA Green Section agronomiststraveling throughout the bermudagrasszone and southern transition zone.Virtually all courses use a curative pro-gram, and some courses with ultra-dwarf putting greens have never experi-enced a disease.

The presence of mechanical or en-vironmental stress factors may helpexplain the large variation in diseaseincidence from location to location. Inmany cases where disease is a problem,there is an existing stress factor thatinduces or exacerbates disease injury.Light, frequent vertical mowing, poorwater quality, mower scalping, shade,and prolonged cloudy or rainy weatherare stress factors to watch out for.

Fertility: This is one of the least-understood aspects of ultradwarf man-agement. There is no clear consensusamong researchers regarding optimumlevels of N, ~ and K fertility for each ofthe varieties. To further complicate theissue, it is possible that the differentultradwarf varieties may require differ-ent fertility programs, particularly nitro-

SEPfEMBER/OCTOBER 2001 3

gen rates (White, 2000b). There havebeen examples of poor performance atboth high and low rates of nitrogen.Reducing the typical annual nitrogenprogram for Tifdwarf greens by 25%appears to be working reasonably well.Additionally, these clubs are findingthat making scheduled applicationsmay not be the best method. Instead,better success has been reported usingobservational techniques such as clip-ping production, color, and the densityof the stand to schedule fertilizer appli-cations. Spoon-feeding with liquidfertilizer has been widely used withexcellent results, too.

Growing Conditions: Excellent siteand soil conditions are a prerequisitefor success with every turfgrass variety.Shade levels, rootzone quality, puttinggreen size, irrigation coverage, andwater quality all affect the health of anultra dwarf. Many feel that ultra dwarfsare even less shade tolerant than Tif-dwarf. While providing good growingconditions may seem like commonsense, it is shocking how many golfcourses compromise plant health byfailing to address these factors. A mini-mum of eight to 10hours of full sunlightdaily is recommended, or poor perfor-mance will result. Providing the bestgrowing environment is every bit asimportant as selecting the right variety.

Winter Hardiness: As ultra dwarfsreplace bentgrass putting greens inthe southern portion of the transitionzone, protection against winter injurybecomes more important. The relativecold hardiness of the ultradwarfs versusTifdwarf is not completely understoodat this time, although it seems there islittle difference from observations inthe field. Winter injury has been docu-mented on ultradwarfs during the coldwinter of 2000-2001 when tempera-tures reached as low as 0 to 10 degreesand covers were not adequately used.The use of covers during the winterwhen temperatures drop below 25degrees F dramatically reduces the riskof winter injury.

Overseeding: Early in their develop-ment, there was concern that the ultra-dwarfs were too dense to overseed. Thisthinking has changed with the suc-cessfull establishment of Poa trivialisoverseeding on all the ultradwarfs.Transition problems do not appear tobe more or less severe than with Tif-dwarf.

The percentage of golf courses thatoverseed their ultra dwarfs is declining,however. One reason why courseschoose not to overseed is the ability to

4 USGA GREEN SECTION RECORD

set up the entire management programaround the requirements of the ultra-dwarf. This results in even better putt-ing green performance during thewarmer months. The fact that several ofthe ultradwarf varieties maintain greencolor during the fall is another reasonwhy many courses are not overseedingultra dwarf putting greens.

Putting on dormant or semi-dormantultra dwarfs has been widely acceptedby golfers during the colder months.High green speeds, firmer surface con-ditions, and some wear are the primaryliabilities on putting quality during thewinter. Raising the mowing height to %2or 3/16 inch prior to dormancy is neces-sary to avoid excessive winter greenspeeds and to improve wear tolerance.

Encroachment: The encroachmentof surrounding fairway type bermuda-grass varieties from the collars into theputting greens has not been an issuewith the ultradwarfs. It appears the highturf density of these new varieties andthe lower mowing heights employeddiscourages encroachment into theputting greens.

Off- Types or Mutations: No one iscertain whether off-types or mutationswill appear in ultra dwarf puttinggreens, but the track record to date isspotless, with no off-types reported.This may be the result of superiorgenetic stability or stricter managementof ultradwarf growers. This is quite achange from Tifdwarf greens, where off-types could be expected to appear afterfive or six years and regrassing wasexpected after 15 years.

The management protocol for main-taining a healthy ultradwarf is a depar-ture from traditional Tifdwarf manage-ment, but it is not considerably moreexpensive or time-consuming if all theproper equipment is in place. This is acritical point to remember because itsuggests that even mid- to low-budgetgolf courses can commit the resourcesto having healthy ultradwarf puttinggreens. The Aiken Golf Club, Aiken,S.C., and the Country Club of Lexing-ton, Lexington, S.C., are successfullymanaging TifEagle on budgets of lessthan $300,000.

Managing for PlayabilityWith a healthy turfgrass base, man-

aging an ultra dwarf for optimum play-ability can be fun. Historically, super-intendents were required to manageTifdwarf putting greens on the edge offailure to achieve the best playability.All this has changed with the ultra-dwarfs. Superior putting conditions

can be provided on an ultradwarfwith-out unduly sacrificing plant health. Thelevel of quality achieved is a function ofthe effort expended, and this is wherecosts can vary widely.

The golf courses with the best ultra-dwarf greens commit the most re-sources and time to the putting greens.Quality has a price. The questions fora golf course considering an ultra-dwarf include, "Is that price withinour reach?" For many golf courses, theanswer is a resounding "yes," and hereis why. Sixty percent of the game ofgolf involves the putting greens, but onaverage only 15% of the budget is spenton putting green maintenance. If thebudget cannot be raised, some portionof the 85% of the budget spent on otherparts of the course is available to bereallocated. Examples of reallocationinclude naturalizing pond and creekbanks, eliminating unnecessary land-scaping on the course, or reducing theintensity of bunker maintenance orother labor-intensive hand work. Thereis nowhere else on the golf coursewhere such a small increase in costscan have such a dramatic impact onplayability.

The extent to which a course with anultradwarf can elevate putting quality isa function of available equipment andthe staff to carry out a predeterminedschedule. Outlined below are the areasthat most influence ultra dwarf perfor-mance. The list is not all-inclusive, butit provides the essential elements foran ultra dwarf management program.Utilization and frequency can varybased on the geographic location wherethe ultradwarf is being grown and onthe desired level of quality.

Mowing Equipment: Mowing has thelargest influence on the quality of anyputting green. The ability to mow loweron a regular basis results in approxi-mately one to one-and-a-half extrafeet of ball roll compared to Tifdwarf.Generally, walking mowers producethe highest quality of cut and arerecommended, but triplex mowing canproduce excellent ultradwarf puttingsurfaces, too. Mowing heights seen inthe field on ultradwarfs have rangedfrom .090 to .150 inch.

Many courses find that it is beneficialto have two fleets of mowers. Theprimary fleet is used for daily mowing,while the secondary fleet, comprised ofsecondhand mowers, is used after sandtopdressing.

Mowing frequency has a tremen-dous influence on putting quality, too.Double mowing is performed regularly

at some courses to further improvegreen speed and smoothness. Criticsclaim frequent double mowing is tqkingmanagement to an extreme. Supportersargue that the extra speed and smooth-ness achieved with double mowing arewell worth the extra cost.

Specialty equipment for the mowersrounds out a high-quality managementprogram. Groomers and brushes allhave a place in the program.

Equipment Maintenance: The, bestagronomic program can be writtep onpaper, but unless the equipment ismaintained to a high level, the desireddegree of quality will never be reached.The mechanic at a golf course with anultradwarf can make or break thesuccess of the program. As mowingheights move lower and lower, theamount of time necessary to set upand maintain the mowers increasesdramatically. Daily backlapping is agiven today, and bedknives are replacedas frequently as every two to threeweeks. Golf courses with the higheststandards find it is necessary to haveat least one additional employee dedi-cated to working with the mechaniceach day.

Rolling Equipment: The practice ofrolling putting greens is an excellentway to temporarily increase greenspeeds by as much as 10% (Hartwiger,1996). One or two rollers are recom-mended for courses that desire tofurther enhance putting quality. Manycourses are finding the need for rollingis reduced because of better speedscreated through lower mowing andmore frequent topdressing.

Topdressing Equipment: Topdressingmachines that have the ability to applylight and heavy amounts of sand areessential. The now rotary spinner top-dressers have the ability to deliver light

Tifdwarfbermudagrass isplagued withcontaminationand off-types,which disruptuniformity. Todate, this has notbeen a problemwith theultradwarfvarieties.

dustings of sand to improve smooth-ness and dilute the accumulation oforganic matter. A traditional topdresseris recommended to fill aeration holeswith sand.

Aeration Equipment: Two or threeaerifiers are recommended to completescheduled aerations on a timely basis.Some coufses are obtaining water in-jection machines such as the ToroHydroject or using 1/4 quadratines ontheir regular aerifier to use in thesummer to avoid surface sealing.

Making an U1tradwarf WorkMagic is not required to make an

ultradwarf a success at a golf course.Plant health can be maintained with areasonable amount of effort, and play-ability is a function of staff expertise,equipment, and labor. The final pieceof any successful ultradwarf manage-ment program involves the humanelement.

Attitude of the Golf Course Owners:The putting greens must be the focalpoint of every golf course that wishesto succeed with an ultra dwarf variety.Shortcuts in the equipment fleet andthe frequency of routine maintenanceare a formula for disappointment. Themost successful clubs focus on theputting greens, provide the equipmentand staff recommended in this article,and commit to carrying out the pro-gram. They also are open to change inthe management program, as the turf-grass manager learns through experi-ence and research.

Skill and Attitude of the Superinten-dent: The ultradwarfs are still in theirinfancy. Management programs areevolving as more information becomesavailable. Individuals uncomfortablewith change will not be the best man-agers for ultradwarf putting surfaces.

The most successful managers welcomethe chance to elevate putting condi-tions and enjoy the challenge of dis-covering the best maintenance prac-tices for that specific location.

ConclusionWe are experiencing the best ber-

mudagrass putting conditions ever inthe history of the game. The ultra dwarfvarieties are nothing to be afraid of,and with the right commitment andresources, they should be embraced. Asresearch is conducted on and off thegolf course, the potential for the ultra-dwarfs will be fully realized. Take thetime to understand what it takes tomake an ultradwarf a success, becausethe next time you hear the comment"the ultradwarfs are not for everybody,"you will know exactly what they mean.

ReferencesBeard, J. B., and S. I. Sifers. 1996. Newcultivars for Southern putting greens. GolfCourse Management. 64(12):58-62.Gray, J. L., and R. H. White. 1999. Main-taining the new dwarf greens-type ber-mudagrasses. Golf Course Management.67(3) :52-55.Guertal, B., and R. H. White. 1988. Dwarfbermudagrasses demand unique care. GolfCourse Management. 66(7) :58-60.Hartwiger, C. 2000. Give me your poor,your tired, your dead bentgrass greens.USGA Green Section Record. 38(3) :7.Hartwiger, C. 1996. The ups and downs ofrolling putting greens. USGA Green SectionRecord. 34(1-4).Hanna, W 1998. The future of bermuda-grass. Golf Course Management. 66(9) :49-52.NTEP Website www.ntep.org. 2000. Evalu-ation of bermudgrass for putting greens.Progress Report 1999. NTEP No. 00-7.Unruh, J. B., and S. Davis. 2001. Diseasesand heat besiege ultradwarfbermudagrasses.Golf Course Management. 69(4):49-54.White, R. H. 1999. Unleash the potential ofnew bermudagrass cultivars. USGA GreenSection Record. 37(5):16-18.White, R. H. 2000. Relationship of environ-ment, management, and physiology tobermudagrass decline. p. 27.In J. L. Nus andM. P. Kenna (eds.), 2000 Turfgrass andEnvironmental Research Summary. UnitedStates Golf Association, Far Hills, N.J.White, R. H. 2000b. Performance and man-agement of new dwarf bermudagrasses.2000 Annual Research Progress Report.pp. 1-24.

CHRIS HARIWIGER is on a first-namebasis with the ultradwarfs in his travels asa USGA Green Section agronomist through-out the Southeast and Florida.

SEPrEMBER/OcrOBER2001 5