Tahoma 31

Drought Resistant Sod

Oklahoma University’s Professor of Grass Breeding and Genetics, Dr. Yanqi Wu, is passionate about hiking in some of the world’s most extreme climates. During those hikes, he sources unusual plant varietals including the grasses used to create Tahoma 31, which has the varietal name of OKC 1131.

In 2006, Dr. Wu, along with his university turfgrass team, grew the parent plants. In 2007 the seeds were germinated at the university’s Agronomy Research Farm. Over 10,000 progeny were created from the crossbreeding, and the selection process began. Only 1600 plants remained by 2008 and they entered outdoor trials. The winter of 2010 in Stillwater, Oklahoma, saw extreme levels of cold, killing most of the 1600 plants. That is with the exception of plant #31, which grew healthy and dense the following spring. This varietal was handpicked for more trials at the university in 2011.

Following over 10 years of research at the university and at various research centers around the country with NTEP, the grass was shown to have several beneficial qualities. OKC 1131 was licensed to Sod Production Services in 2017 and the name Tahoma 31 was selected for this new variant. Tahoma is a native American word for ‘frozen water’ which seemed to be apt.

Dr. Wu explains that grass is a unique genotype combining genetic factors for hardiness in cold climates via gene contribution and parent-plant interaction.

Dr. Yanqi Wu

Drought Resistance

Superior drought resistance was shown by Tahoma 31 over 4 other standard cultivars. Compared to the TifTuf varietal, it averaged 18% less water requirement. Dr. Wu bred Tahoma 31 with the aim of better drought resistance, as that was the goal set by the US Department of Agriculture. The deep roots of Tahoma 31 enable it to grow healthily with a reduced water amount.

Oaks Country Club: Drought Case Study

This grass was planted in the fringes of 18 holes at Tulsa’s Oaks Country Club in 2016. The golf course superintendent, Dan Robinson, who has been there for over 10 years, explains that Tulsa typically has a dry, cold winter season. Since the greens do not need much winter irrigation, fringes or collars have to be watered by hand. A different bermudagrass had been tested prior to Tahoma 31. It failed to survive 2 consecutive winters, requiring replacement. Robinson says the Tahoma 31 is shown to be drought-resistant.


‘Last year was very dry and cold,’ Robinson said, ‘We lost other varietals of collar grass to either drying out during the coldest months or desiccation. But the same is not true of Tahoma 31, which has survived the past 2 winters. Rather than having to replace up to 20 pallets every year, we only had to replace one pallet of Tahoma 31. It is the best grass we have used.’

Dr. Justin Moss

Of all the genotypes tested, TifTuf was shown to have the highest levels of evapotranspiration (ET) while Tahoma 31 had the lowest, in 2013, 2014, and 2015. These differences in rates of ET are a useful method of showing breeding program potential outcomes. Cultivars with low ET rates can be bred for reduced overall evapotranspiration requirements. The lower the ET the better for water efficiency.


According to Dr. Justin Moss, OSU, drought resistance refers to the ability to tolerate and avoid drought. Drought tolerance + drought avoidance = drought resistance. Tahoma 13 shows it is able to grow deep, extensive root systems to help protect it from drought. Its low water requirement compares favorably with other cultivars of bermudagrass and in field conditions, it’s a very good type of grass.


Dr. Dennis Martin, also from OSU, says Tahoma 13 will grow into a great lawn and have lower water usage rates as well as better water use efficiency when compared to other types of bermudagrass.

Cold Hardiness

Tahoma 31 bermudagrass has one of the lowers rates of winterkill compared to every bermudagrass that was tested in NTEP, with the following winterkill rates:

  • TifTuf: 3%
  • Tifway 419: 98%
  • Celebration: 98%
  • Tahoma 31: 4%


Sod examples

Cold Hardiness

“Tahoma 31 can survive even harsh winters,” says golf superintendent Dan Robinson, where all 18 greens had this grass in the collars since spring 2016. “Other grasses were used the 2 years prior and neither survived. We have been using it for 2 years around the golf course and have only had to replace 1 pallet of it. Last winter was incredibly cold and dry but still, the Tahoma 31 thrived. This grass is seriously drought-tolerant.”

University of Arkansas

Professor of Turfgrass Science, Dr Doug Karcher, has the following to say about this grass: “It performed remarkably in the bermudagrass NTEP trials.

Tahoma 31 has great color, texture, and density, and tolerates the cold very well.”

Oklahoma State University

OSU’s Dr. Yanqi Wu describes it like this: “It is a unique genotype, pairing genetic factors favorably with the result Tahoma 31 is extremely cold hardy via genes and interaction from two plant parents – 

one from Africa and the other from Asia.”

Advantages of Tahoma 31

This grass varietal is versatile and offers a number of benefits:

Look and Feel

The leaf blades are dark green with a fine texture and high density. When compared to other commercial grasses, Tahoma 31 is able to better withstand very cold temperatures and greens up quicker in the spring.

Salt Tolerant

Tahoma 31 ranked #1 for salinity response out of 10 experimental types of grass plus Tifway, an older cultivar.


After being tested in 19 areas across the US, Tahoma 31’s turfgrass quality ranked in the top 25% of every grass variety 78.5% of the time, proving it’s highly adaptable.

Low Mowing Height

Tahoma 31 does best when cut at a height of 0.125 inches, according to Dr. Wu, Oklahoma State University’s Professor of Grass Breeding and Genetics. Tahoma 31 was tested between June 1 and August 30, 2018. Results showed it was tolerant of low mowing heights and are also suitable for use on municipal or public golf course greens, using specific maintenance requirements.

Wear Tolerant

Dr Yanqi Wu explains this grass is very aggressive. It heals rapidly from sports-related wear and damage.

Density, Beauty and Tolerance to Cold

65,000 square feet of Tahoma 31 were planted in 2017 at Shangri-La Golf Club & Resort, Monkey Island, Oklahoma, on the event lawn. At 2018’s Fourth of July celebrations, the grass drew more attention from the guests than the hot dogs and fireworks combined. Justin May, golf course superintendent, said the hundreds of guests preferred to sit in the lush, soft grass than in the seats provided. Many people asked May where they could get Tahoma 31 because they had never felt or seen anything like it before.


Jerad Minnick, Natural Grass Advisory Group’s lead adviser planted Tahoma 31 on 2 Maryland sports fields. He found the strength and aggressive nature of this grass, even when planted late in the season, very impressive.


Brad Sherry, Sod by Sherry’s owner, says they expect this grass to be a popular choice with both sports facility managers and housing developers, where year-round healthy grass is important.


Dr. Doug Karcher, the University of Arkansas Professor of Turfgrass Science, says their NTEP trial was kept at ½-inch high, which is the height of highly managed sports turf and golf course fairways. He considers Tahoma 31 to have great potential for the area’s highly managed systems.

Tahoma 31: Additional Data

This bermudagrass, with the varietal name OKC 1131, was tested at Stillwater’s Oklahoma State University, in diverse regional experiments. It was then tested in the 2013 NTEP National Bermudagrass Test more extensively (accessed in January 2017) which showed data from 17 locations in 2013 and 2014, as well as from 19 locations in 2015.

Comparative Performance and Strengths

A high-quality, interspecific hybrid turf variety, Tacoma 31, has shown excellent winter survival as well as wide adaptation and great drought resistance. This grass has shown top-notch establishment characteristics, high turf density, dark green color, and early green-up. Plus, it had enough sod tensile strength to ensure reliable commercial production.

Wear Testing and Establishment Rate

According to the 2013 NTEP test, data shows Tahoma 31 has very high establishment ratings at all locations. In the KY2 traffic trial, it shared a similar establishment rate with Patriot and Celebration, and a faster one than TifTuf, Tifway, and Latitude 36.

Sod sample
Sod closeup

Turf Quality

Tahoma 31 turf quality was averaged in all locations on a scale of 1 to 9 (with 9 being the best) and was in the best-performing group in 2014, 2015, 2016, and 2017, as detailed in the 2013 to 2014 progress report, 2015 progress report, 2016 progress report, and the 2017 preliminary report.

Drought Resistance

An NTEP test field trial ran from August to October 2015 in College Station, Texas, to examine living ground coverage and turf quality under drought conditions. The two top-performing grass varieties were Tahoma 31 and TifTuf. For the drought test, the percentage of living ground cover ratings for Tahoma 31 were the same as for TifTuf in 8 of the 12 events. But, Tahoma 31 did better in 1 event, showing better living ground coverage for 9 events than Latitude 36 and for 3 events than Celebration and Patriot. Patriots beat Tahoma 31 in LGC in the drought test on one date.

Vertical Growth Rate

One desired trait in turfgrasses is a low vertical growth rate since this reduces the frequency of necessary maintenance and/or mowing. In 2014, a replicated field trial was established, and findings showed Tahoma 31 had the lowest vertical growth rate of all tested industry standards.

Water Requirements

Water use rates were evaluated in a field-based trial using 10 well-watered Cynodon spp. bermudagrass genotypes in a totally randomized block design. By using 3 replications with mini0lysimeters and calcined clay for the rooting media. This trial was conducted from May to June 2018, at the OSU Turfgrass Research Center, in Stillwater, OK. The study was called ‘Evapotranspiration Rates of Turf Bermudagrasses under Non-limiting Soil Moisture Conditions in Oklahoma’. It measured evapotranspiration (ET) rates before dawn by weighting every mini-lysimeter once every 24 hours for 10 days in 2013, 10 days in 2014, and 8 days in 2015. Tahoma 31 ranked consistently in the lowest ET group while TifTuf ranked consistently in the highest ET group. When averaged over the 24 different dates in those 3 years, it was found that Tahoma 31 used 0.89 mm d-l or 18% less than its competitor TifTuf.


Very cold temperatures were experienced in the 2013 and 2014 winters at various northern NTEP test sites. Tahoma 31 was found to have the lowest winterkill rating. According to this report, Tahoma 31 had a 25% winterkill rate (the scale was 99% and 99% represented total kill) compared to Tifway’s 99%, Celebration’s 98.7%, TifTuf’s 94%, Latitude 36’s 73.3%, and Patriot’s 50%, in Lexington, KY. According to this NTEP test, Tahoma’s winterkill rate was 4% – a lot better than Tifway’s 98%, Celebration’s 97.3%, TifTuf’s 82.7%, and Patriot’s 11.7%. The rate was not different from Patriot’s 11.7% or Latitude 36’s 41.3% in West Lafayette, IN. There is no winterkill information available for the 2014 and 2015 winters.

Spring Green Up

Tahoma 31 does not suffer much damage during the winter, so it had higher spring green-up ratings than its competitors. Tahoma 31 was rated 6.0 and 6.1 green-up, while Latitude 36 was rated 5.3 and 5.4, and Patriot was rated 4.8 and 4.5. Tifway came in at 4.1 and 4.7, Celebration was 3.7 and 4.5, and TifTuf came in at 5.2 and 5.6. The early spring green-up Tahoma 31 offers clearly demonstrates its excellent winter hardiness.

Tahoma 31 is a wear-tolerant, cold-hardy, drought-resistant grass, offering early green-up, and a fine and beautiful texture. This type of bermudagrass is ideal for lawns, sports fields, and golf courses.

Tahoma 31