A New Look at an Old Bentgrass
Ask turfgrass managers what they consider to be the best attributes a turfgrass can have and immediate answers include increased density, color and texture as well as the highest possible environmental stress, disease and insect resistance. These comments would immediately be followed by specific attributes, such as tolerance to shade and drought, low fertility requirements and a high degree of aggressiveness for increased recuperative potential and weed competition. Suggestions as to which species and varieties have these attributes would then range all over the board, most likely without including a logical and appropriate, although often overlooked, choice: velvet bentgrass.
Velvet bentgrasses are a true native to the northeast region and can still be seen growing exceptionally well on older estates, parks and golf course fairways and roughs that were constructed more than 100 years ago. However, this species fell out of favor more than 40 years ago when golf course management programs began favoring the “new” creeping bentgrass varieties, which required much more maintenance, such as more nitrogen and irrigation, along with an increased need to rely on pesticides. Through the years, creeping bentgrasses have been evaluated in side-by-side trials with velvet bentgrasses using the high-maintenance inputs described above. This high-maintenance care caused the velvets to rapidly decline and go out of stand because they were simply being “managed to death.” Mismanagement coupled with poor seed production and a general disinterest by the major seed companies put velvet bentgrass into obscurity until recently when Leah Brilman, Ph.D., a turfgrass breeder, recognized the natural attributes of this species and how they are a good fit in today's low input IPM world of turfgrasses.
MAKING A COMEBACK
Velvet bentgrass is a low input turfgrass that has the finest leaf texture and highest shoot density of all the turfgrasses and possesses exceptional drought, shade and disease tolerance while requiring very low levels of nitrogen fertility. Through the efforts of Brilman and a number of university breeders and researchers, new and improved varieties of velvet bentgrass are now available and have been successfully used on golf courses throughout the United States and Canada for the past 10 years. In fact, a number of courses have actually seeded velvet bentgrass to tees and fairways along with greens and have found that the higher heights of cut are resulting in an exceptional quality playing turf. These results have lead to the question: Why not use velvet bentgrasses in the landscape?
For the past several years, I have evaluated a number of golf courses and private estates that have established the new varieties of velvet bentgrass at relatively high heights (up to 2.5 inches) of cut showing a surprisingly high level of turf quality with low maintenance inputs. The possibility of using velvet bentgrasses in the landscape was effectively (and strongly) demonstrated last year when visiting Clif Staples, a landscape and turfgrass specialist and consultant in the Bar Harbor region of Maine. Staples has been using the improved varieties of velvet on high-end estates and golf courses throughout the region for the past several years and has gained a level of appreciation from clients that is second to none. Through the years, Staples has experimented with a number of mowing heights, fertility levels and basic cultural practices and has generated a cultural program for the velvet bentgrasses that can be used as a “template” in other regions of the country.
Staples establishes velvet lawns with a relatively high seeding rate (between 2 to 3 pounds per 1,000 square foot) with 0.5 pounds nitrogen (N) per 1,000 square foot with a quick-release, soluble fertilizer formulation having 20 percent natural organic nitrogen. Late spring and summer germination rates average six days with diligent watering and mowing begins three weeks after germination at 1 to 1.5 inches weekly. Staples maintains velvet lawns with no more than 2 pounds N per 1,000 square foot with half of that as a natural organic fertilizer source during the summer months and has experienced very little disease activity with leaf spot and red thread occasionally occurring in early to mid-spring. His maintenance program is almost fungicide-free, with maybe one application to control rhizoctonia or pythium during the hot, humid summer period. Increasing mowing frequency and removing dew off the turf through syringing has proven to be important and effective in this dense turf during periods of high-disease activity. Once established, the density and aggressiveness of velvet bentgrass virtually precludes any use of herbicide and successfully eliminates encroachment of annual bluegrass (Poa annua). The photo on page G1 illustrates how successful a velvet lawn overwinters in the Bar Harbor area. Pink and grey snow molds have, in some years, been active with no observable negative effects.
Left unmanaged, thatch produced by velvet bentgrasses can become problematic due to the high turf density and lateral growth. You'll need to perform aggressive, deep annual verticutting in early spring to remove hydrophobic thatch and relieve compaction (see the top photo on page G2). After overwintering and verticutting, velvet bentgrasses exhibit aggressive recuperative potential and growth rates once soil temperatures exceed 55°F to 60°F. Staples has been using ‘SR-7200,’ produced by Seed Research of Oregon, because this was the “breakthrough” improved cultivar and essentially the only choice for the past 5 to 6 years. ‘SR-7200’ has been extensively tested by the National Turfgrass Evaluation Program (NTEP) with superior results producing a pleasingly dark colored, very dense turfgrass stand (see the bottom photo on page G2 and the photo above). At present, there are not many improved varieties available; however, within the past several years, other seed companies have taken notice of the exceptional qualities of velvet bentgrasses and have been actively breeding/selecting and testing new varieties, which have recently become available. Mixtures of these varieties are recommended to increase the genetic diversity within the turfgrass stand and enhance the already high levels of environmental stress and disease tolerances.
IMPROVED AND ADAPTED
The most important challenge facing turfgrass managers is the development of successful IPM programs that can achieve their goals while still maintaining economic feasibility. Improved velvet bentgrasses represent a very significant and powerful tool (albeit neglected until now) in the development of such programs. Velvet bentgrasses are now known to be adapted to a wide range of environmental conditions and use throughout most of the northern tier of the United States is possible. Considering that velvet bentgrass is highly tolerant of shade, drought and low temperatures as well as being one of the most disease resistant and low maintenance turfgrasses available, it makes economic and environmental sense to consider using it not only for golf courses but for home and estate applications as well.
William A. Torello, Ph. D., is retired professor of turfgrass management from the University of Massachusetts and currently president of Professional Turfgrass Consulting, Inc. Torello can be contacted at firstname.lastname@example.org.
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