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prepared by Stacie Zinn

Cold hardiness in grasses in general, and Seashore Paspalums specifically, vary by cultivar. According to Dr. Ronnie Duncan, noted paspalum expert and author of Seashore Paspalum: The Environmental Turfgrass, “the course textured (paspalum) ecotypes exhibit the least cold hardiness and generally, the finer the leaf texture, the greater the cold hardiness.” As SeaDwarf™ Seashore Paspalum has the finest leaf texture of all the paspalums, then, it may be extrapolated that SeaDwarf™ offers the most cold hardiness of all of the paspalums.

In addition, in his book Duncan states that the “fine-textured ecotypes also will generally be the last warm-season grasses (2-3 weeks later) to go off-color and it normally takes about 26 degrees for them to completely shut down and go into full winter dormancy.”

Test sites and other research sources have yielded the following results:

1. New Mexico State University: A SeaDwarf™ test site at New Mexico State in Las Cruces was established in May 2004. Dr. Bernd Leinauer and his research staff rated SeaDwarf’s performance at the site as “excellent.” In describing winter color, Dr. Leinauer said “Didn’t brown like bermudagrss. Did go off color.” Statistics show the historical January mean daily minimum temperature in Las Cruces is 26.1 degrees. Not surprisingly, the grass eventually did go dormant during the test period. Yet, through the cold temperatures, Dr. Leinauer said there was “no noticeable winter kill.”

2. University of Arkansas: A SeaDwarf™ test site at University of Arkansas Horticulture Field Laboratory in Fayetteville was established in August 2004. The average daily temperature in Fayetteville in January is 34 degrees. Dr. Doug Karcher found that SeaDwarf went dormant after the “first frost.”

3. University of Florida: Volusia county Agricultural Center reports in the June 2005 issue of Green-Up News that SeaDwarf ™ has “improved winter color and salinity tolerance over SeaGreen.”

4. Overseeding: A May 2002 article by Dr. Ronnie Duncan in Turfgrass Trends magazine stated that Seashore Paspalum “ can be overseeded with most cool-season grasses, but the dense canopy warrants use of a verticutter to ensure good seed-soil contact for the cool-season grass.”

5. Turf News: A March 2005 article in Turf News magazine featured an interview with J.R. Wirthlin, a SeaDwarf™ grower in Southern California. An excerpt from the article reads: Wirthlin began to investigate other options and found that SeaDwarf Seashore Paspalum takes up to 50 percent less water for irrigation than bermudagrass, and generally won’t go dormant in the Southern California climate. “So I flew out to Florida to take a look at it, and brought a half a roll home. I plugged some right in the middle of my TifGreen lawn, and my dad plugged some right in the middle of his bentgrass lawn. We kind of just let it rest there. I didn’t commit,” Wirthlin said. “And after we went through the winter, my own wife was saying, ‘That’s what we want. Get rid of the TifGreen. I want that.’ The TifGreen didn’t go dormant, but it went yellow. And the SeaDwarf, we had this big round green spot right in the middle of the lawn.” Wirthlin continued, “That’s when I realized that, yeah, we were onto something different. Not improved. Not upgraded. We truly have a variety that in my opinion is a revolution, not an evolution.”

6. Hollywood Park: Hollywood Park, the turf horseracing track in Inglewood, California, recently regressed its Bermudagrass racetrack with SeaDwarf™. Prior to installation, superintendent John Barrios did a trial with the grass. It was planted in the fall of 2004 and was evaluated over the winter months. In a press release from the facility, Barrios said, "Climate plays a major factor. Before making any decisions, numerous tests were run, both at labs and physically on the track… The new turf has more cushioning than we have experienced with the Bermuda because of its density. It is more cold tolerant, it roots much faster, and it grows at a much cooler soil temperature than Bermuda."

7. Michigan: At a seminar titled “SeaDwarf Seashore Paspalum: Uses and Adaptations” held during a meeting of the South Texas Golf Course Superintendents Association on Galveston Island, June 14, 2004, researcher Michael Depew, who characterizes himself as having “worked extensively with this grass,” stated that he had tested SeaDwarf™ on his home lawn in Michigan for six years and the grass “did not experience winter kill.” Depew said the grass has a “substantial threshold for cool weather and color retention,” stating that temperatures had to be “down in the teens for several days before it goes off-color.” When the grass does go off-color, Depew said, it will “first get purpling,” and added it “takes about three weeks of subfreezing temps to get it to go brown.”