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Key Takeaways

  • Ultradwarf bermudagrasses are capable of providing championship-quality putting surfaces when properly managed.
  • Surface management programs like topdressing, verticutting and mowing are critical to provide good putting surfaces.
  • Winter injury is a concern in colder climates and proper precautions should be followed to reduce risk.
  • There is no one-size-fits all program for ultradwarf management, but these practices are fundamental to produce high-quality surfaces for 49 weeks of the year – allowing a few weeks for the necessary disruption of aeration.

Bermudagrass greens have come a long way since the days of ‘Tifgreen’ and ‘Tifdwarf’ in the mid-to-late 1900s. Since then, ultradwarf mutations from ‘Tifdwarf’ – such as ‘TifEagle’, ‘MiniVerde’ and ‘Champion’ – have been widely used throughout the southern part of the country. While the ultradwarfs were first used as an alternative to bentgrass because of their reliability in summer, many courses have proven that these grasses can provide championship-quality conditions throughout the year when properly managed. Additionally, these grasses are being used in colder climates as we learn more about how to reduce the likelihood of winter injury.

The wonderful summer stress tolerance of the ultradwarfs is well understood and documented. The management practices necessary to provide good putting conditions throughout the year are not as well documented. Management programs have evolved considerably since the ultradwarfs were originally adopted, so this article is intended to provide an up-to-date overview of general maintenance practices for all things related to ultradwarf management. Whether you’re considering a conversion or trying to stay up to date on the latest trends in ultradwarf management, this article is for you. However, it is important to remember that there is no one-size-fits all program for managing any turf type. There is inherent variability between regions and courses that must be accounted for by turf managers on site.

Where Did Ultradwarfs Come From?

Bermudagrass breeding for golf courses began in the U.S. in the mid-1940s in Tifton, Georgia. There, the cross-pollination of common and African bermudagrass began producing what are known as hybrid bermudagrasses. These grasses are sterile, meaning that their seed is not viable. A once-popular hybrid, ‘Tifgreen’ (also known as ‘328’) was a result of these breeding efforts and was released in 1956. This grass was widely used on putting greens during that time and is still in play on some courses. ‘Tifdwarf’ was identified as a mutation in ‘Tifgreen’ putting greens. The mutation was selected out of ‘Tifgreen’ putting greens in South Carolina and researchers propagated this field stock and released ‘Tifdwarf’ in 1965. This mutation had finer leaf texture, darker color and could tolerate lower mowing heights than ‘Tifgreen’. Since then, natural mutations in ‘Tifdwarf’ have resulted in the selection of ultradwarf bermudagrasses commonly used today, including ‘MiniVerde’ and ‘Champion’. Another commonly used ultradwarf, ‘TifEagle’, was developed as a descendant from ‘Tifdwarf’, but mutagenic agents were used to induce the mutation in this case.

As it relates to the history of bermudagrass putting greens, it is worth mentioning that the ultradwarfs are capable of providing higher-quality putting surfaces than the older ‘Tifgreen’ and ‘Tifdwarf’ grasses during the summer months and tend to hold up better during winter dormancy, thus reducing the appeal of overseeding. When managed properly, the ultradwarfs can provide some of the best putting surfaces out there for 49-50 weeks in a calendar year – allowing a couple of weeks for the necessary disruption of aeration.

Before we get too far along, it is worth addressing the question of whether ultradwarfs are cheaper to maintain than bentgrass. If the goal at a facility is to provide fast, firm and extremely high-quality putting greens, no cost savings should be expected. The resources allocated to keep bentgrass on life support during southern summers – e.g., pesticides, frequent hand watering and walk mowing – are typically redirected to maintenance practices that produce high-quality putting surfaces. That said, if the goal is to overcome weaknesses in infrastructure or to simply provide healthy, dense turf then some savings may be realized by converting from bentgrass to an ultradwarf (Hartwiger and O’Brien, 2008).

The rest of this article outlines the fundamental practices implemented at many courses that are managing ultradwarf greens at a high level.

Surface Management

Practices such as mowing, topdressing, light verticutting, applying plant growth regulators (PGRs) and water management are some of the most critical components of a successful ultradwarf management program. Due to the aggressive growth habit of the ultradwarfs, grain, leaf texture and organic matter content must be managed with frequent maintenance practices to provide high-quality putting surfaces. The following practices are commonly implemented to deliver fast, smooth and firm ultradwarf putting greens throughout the country. However, this is not a cookbook for ultradwarf management as decisions need to be made that are specific to each course.

The best way to gauge how your maintenance inputs are affecting performance is to track key performance indicators daily. Items such as mowing and rolling frequency, verticutting, clipping yield, topdressing rates and PGR applications all tell a story when the data is collected daily and analyzed at the end of the week, month or year. The USGA DEACON platform was designed to provide turf managers with an easy way to log this data in the field and produce relevant and easy-to-read graphics to help analyze how inputs are impacting performance.

Sand Topdressing

Topdressing is one of the most important inputs required to provide a firm and smooth ultradwarf putting green. Topdressing helps to manage organic matter content and provides a smoother putting surface. As a mentor and longtime USGA agronomist once told me, “Topdressing is to a putting green as slate is to a pool table.”

“Topdressing is to a putting green as slate is to a pool table.”

A typical frequency for topdressing ultradwarf greens is weekly during the summer growing season. Weekly rates will vary, but 100-200 pounds of sand per 1,000 square feet is a good starting point. Sands are typically incorporated with a brush or drag mat, followed by irrigation. Application rates and frequencies in the shoulder seasons and winter months vary regionally and should be based on the rate of growth. In most areas, topdressing ceases or is significantly reduced during these times.

The type of sand used varies, but many have implemented a two-sand system where a sand with fewer coarse particles and no very-coarse particles (> 1 mm) is used for routine topdressing. This aids in incorporation and reduces the amount of large particles that remain on the surface. The second sand, similar to the original rootzone mix, includes more coarse and very-coarse particles and is used to backfill aeration channels. Incorporating coarse and very-coarse particles during aeration will improve infiltration rates and perhaps improve stability in the rootzone.


Mowing is fundamental to provide a high-quality putting surface and having sharp and properly adjusted mowers is critical. Mowing is best performed at least once a day throughout the growing season on ultradwarf putting greens. Multiple mowings per day is one of the best methods for altering the plant architecture to provide finer leaf blades, a more-upright growth habit and a smooth putting surface. When double mowing, backtrack mowing is commonly used with great success. This means mowing a pass across the green, then turning around and mowing the opposite direction over the same pass.

Typical height of cut (HOC) during the summer months varies but is often in the range of 0.100-0.125 inch. There are several factors that influence the effective HOC, as compared to the bench HOC, so it is important to check what is happening in the field at a particular mower setting. Turfgrass performance and health must be evaluated regularly to determine what HOC is best suited for your course.


Light and frequent verticutting should be performed weekly. Some facilities lightly verticut twice weekly and this will help to further manage texture, promote an upright growth habit and manage organic matter. Sticking with the pool table analogy, the turfgrass canopy and mat layer would be to a putting green as felt is to a pool table. Mowing and verticutting are used to manipulate the architecture of the canopy and mat layer to provide upright and fine-textured leaves. Ideally, golf balls should roll on leaf tips and sand – not wide and laterally growing leaves.

The setup for light verticutting is critical. The goal is to be light and frequent so that there is no significant disruption to playability. Use standard verticutting blades set to a depth of approximately 0.00-0.60 inch below the rollers. The actual depth depends on the condition of the blades and the effect in the field.

"The setup for light verticutting is critical. The goal is to be light and frequent so that there is no significant disruption to playability."

Carbide-tipped blades are not ideal for this treatment. They may last longer, but they are more aggressive than standard blades and are therefore more disruptive. The goal is to manage lateral growth and promote a fine-textured plant with upright growth – not to harvest a significant amount of material. If a significant amount of material needs to be removed, verticutting is probably not being performed frequently enough. Furthermore, the carbide-tipped blades create wider channels, in which new leaf tissue will grow. Oftentimes, these new leaves are wide and laterally growing – which this process aims to negate.

Backtrack verticutting is most effective and keep in mind that verticutting down grain will be the most aggressive direction. If too much “pulling” occurs, try verticutting in a different direction – e.g., cross-grain. The last option would be to raise the height. The following bullets outline the backtrack verticutting process:

  • Mow the putting green.
  • Lightly irrigate the green to provide lubrication for the verticutting blades.
  • Backtrack verticut the green. The first pass should be made in the most aggressive direction (down grain) and the second in the opposite direction, but on the same pass.
  • Blow off the debris, if necessary.
  • Roll the green to minimize scalping potential.
  • Mow the green again.
  • After completion, there should be little, if any, disruption to the putting surface.

Growth Regulation

The most commonly used PGRs on ultradwarf greens are trinexapac-ethyl (Primo Maxx) and prohexadione calcium (Anuew). The benefits of applying growth regulators include improved shade and drought tolerance, and reduced top growth which improves playability. A whole article could be written on the use of growth regulators, so for the sake of this article we will cover programs that have been effective in the field and discuss the reasons for their success.

Trinexapac-ethyl has been used for many years on ultradwarf greens to provide growth suppression and improve shade tolerance. Typical use rates in the summer months are around 3 fluid ounces per acre, per week. Rates are reduced in the winter and are often applied at a low rate of 1-3 ounces per acre every two weeks throughout winter. Winter applications help to reduce any surge in growth that may otherwise occur during a stretch of warm weather.

Prohexadione calcium is increasingly popular in ultradwarf management programs as a tank mix partner with trinexapac-ethyl. The intent is to help suppress mutations – i.e., off-types. Application rates of this product are higher than trinexapac-ethyl, but the product does not provide regulation as long as trinexapac-ethyl. Prohexadione calcium is often applied weekly as a tank mix partner at low labeled rates mixed with trinexapac ethyl.

Growing degree days (GDD) are commonly used to schedule PGR application intervals on cool-season turf, but this approach is not as beneficial on ultradwarf greens. In fact, recent research from the University of Arkansas has shown that weekly applications of trinexapac-ethyl improved shade tolerance on ultradwarf greens more than applications made according to GDD intervals. Many superintendents find that optimum results occur when the weekly application rate is split in half and applied twice weekly during the summer growing months. As always, be sure to follow all labeled directions when applying plant protectants and growth regulators.


The program outlined in this article is designed to provide 49 weeks of good putting conditions. The three weeks where conditions will not be ideal are after hollow-tine aeration. Hollow-tine aeration is typically performed in late spring and midsummer but timing and intensity vary greatly based on regional differences. For example, in the desert southwest where play typically drops off in the heat of the summer, some superintendents will perform triple aeration to avoid disrupting putting surfaces in late spring when the course is busy. Monitoring organic matter content through regular testing is a great way to understand trends over time and allows managers to make more-informed decisions regarding aeration intensity and frequency.

Disease Control

Diseases that affect ultradwarf greens are most evident when growth and recovery potential is slow. Therefore, preventative measures are most effective. Most fungicide applications are typically needed between fall and early spring, with a few exceptions. Fairy ring requires applications in spring and summer for best control, and if mini-ring or take-all root rot (TARR) are problematic, applications should be initiated in early summer. Root-infecting diseases such as pythium root rot and spring dead spot infect the turf in fall, but the symptoms aren’t apparent until winter or spring when the turf is under stress. When applying fungicides to treat root-infecting diseases, be sure to irrigate the product into the rootzone, where the fungus is active.

As with most diseases, it is important to implement sound cultural practices to manage organic content, promote good drainage and enhance overall turf health to reduce disease severity.


Fertility needs vary based on location and length of growing season, but common practices include a larger application of a slow-release granular fertilizer in late spring followed by spoon feeding small amounts of nitrogen fertilizer – e.g., 0.10-0.30 pounds of nitrogen per 1,000 square feet – every one to two weeks throughout the summer growing season. Typical annual nitrogen fertilizer rates for ultradwarf greens are in the range of 4.0-6.5 pounds of nitrogen per 1,000 square feet. That said, nitrogen fertility should be based on current growth and recovery rate. Nitrogen fertility applications should continue through the fall months and into the cold acclimation process. Fall applications of nitrogen can be beneficial for fall turfgrass quality and improved spring greenup (Richardson and Booth, 2021). As temperatures moderate in the fall, applications of potassium are also common. As always, soil fertility tests are the best method to guide your fertility program.

Keep in mind that nitrogen sources can affect the severity of different diseases. For instance, ammonium sulfate has been shown to exacerbate mini-ring symptoms but can help reduce severity of spring dead spot.

Winter Management

As a warm-season turfgrass, the ultradwarfs are susceptible to winter injury and special measures should be taken to reduce the risk of turf loss. Thankfully, extensive research has been performed in this area and a summary of best management practices can be found in the USGA article “Best Management Practices for Preventing Winter Injury on Ultradwarf Bermudagrass Putting Greens.”

One of the most important points to remember is the need to invest in black woven-polypropylene covers to protect the greens when temperatures are forecast to drop below 20 degrees Fahrenheit. Two covers should be used when temperatures are forecast to reach 15 degrees Fahrenheit or lower. Covers should be viewed as an insurance policy – a small cost compared to the cost involved in having to reestablish putting greens following severe winterkill damage.

Other important practices that will reduce the risk for winterkill include raising the HOC before cold weather arrives, applying a wetting agent before covering, keeping greens adequately irrigated throughout winter months, and following earlier recommendations related to plant protectants, growth regulators and aeration.

Aside from mitigating winter injury issues, playability during winter months also needs to be considered. Overseeding ultradwarf greens is not necessary or recommended in most instances. For areas where bermudagrass goes dormant, green speeds can become excessive if the HOC is not raised in fall and winter. This practice also reduces the risk of winter injury, but on non-overseeded ultradwarf greens it is necessary to prevent speeds from becoming excessive during the winter months. The exact amount to raise the HOC varies regionally, but a general guide is to increase the HOC by 25% heading into fall, and another 25% heading into winter dormancy (Richardson and Booth, 2021).


Ultradwarf putting greens have come a long way since they became popularized in the 1990s. We now have a much better understanding of the maintenance practices that will provide good putting surfaces for a majority of the year. These grasses are well suited for portions of the transition zone and farther south and their use will only continue to grow. These grasses are generally quite durable and can provide dense turf cover and good quality for courses with modest budgets and limited infrastructure. Ultradwarfs can also deliver championship-quality conditions throughout much of the year if the resources are available for consistent surface management throughout the growing season. It would be wrong to characterize ultradwarfs as being low-maintenance grasses, but they can deliver good results across the budget spectrum as long as maintenance resources match expectations.


Richardson, M., and J. Booth. 2021. Best management practices for preventing winter injury on ultradwarf bermudagrass putting greens. USGA Green Section Record. November 5. 59(20).

Hartwiger, C., and P. O’Brien. 2008. The ultradwarf investment. USGA Green Section Record. January 10. 46(1).

Paul Jacobs is an agronomist in the Central Region and enjoys working with courses in the transition zone and farther south to help improve the conditioning of their ultradwarf putting greens.