|Creeping Bentgrass (right) does not have the same susceptibility to winter injury as poa annua|
photo: R. Ackerman, Weston GC
- Winter Heartiness. Creeping bentgrass does not have the same susceptibilities as poa annua to winter injury and, therefore, by increasing the percentage of creeping bentgrass in the turf stand, a lower amount of the putting surfaces are at risk during the winter.
- Tolerance of Summer Stress. Once established, creeping bentgrass is a more robust plant and vigorous grower during the higher heat and humidity periods of the summer. It has a deeper root system allowing it be kept in a drier state without drought injury allowing for a firmer, faster surface.
- Salt Tolerance. The level of dissolved salt that is present in the water that the club uses as an irrigation source is very high and presents an acute and long-term risk for the health of the turf and the plants on the property. The current levels of dissolved sodium (Na) and chlorides (cl) are 100-350 ppm for sodium and 300-700 ppm for chlorides. These are 5-15x the desirable limit for healthy turf. Creeping bentgrass has a much higher tolerance of salt stress than poa annua.
- Lower consumption of resources. Poa annua is an annual weed, it invades all turf (and non-turf) surfaces and over an 87 year time span, due to competitive advantages, it begins to make up a higher and higher percentage of the surfaces. In order to keep an annual weed relatively healthy and able to withstand the stress of daily maintenance and golf traffic, a substantial amount of resources in the form of fertilizers, pesticides and water are required to keep the surface optimal, as compared with creeping bentgrass.
|Poa annua (arrow) has a lower tolerance for salt|
Photo: PACE Turf Labs
For these reasons the recommendation to promote the establishment of creeping bentgrass was adopted by the club and the plan was executed through the season. The recommendation came with a note of caution:
"Playability of the putting greens at Cutten Fields and other damaged courses will not approach the typical level of playability they have in the past. The turf is simply too young and too immature. Cutting heights are too high and it has been over fertilized to promote recovery. This leaves it more susceptible to stress later in the year. Thus a conservative approach to maintaining the greens in terms of playability is strongly recommended for this year. The greens are not likely to be as smooth or as fast, but being conservative and preserving turf health will allow the greens to be much better in the long run.
Depending on how much new annual bluegrass becomes established in the greens this year, they my also be somewhat susceptible to problems next year. This is especially true of smaller greens that experience more concentrated wear. It also will be true of greens where growing environments are not improved sufficiently.
There are thousands of types of annual bluegrass and a high percentage of the first ones to invade are the worst ones. They are prolific seed producers and they are the weakest and most stress and disease susceptible types. If a significant amount of weaker AB biotypes become reestablished in the greens, they will be prone to turf loss next year and beyond."
David A. Oatis, Director, USGA Northeast Region4 June 2014, page 6
|The amount of creeping bentgrass on the putting greens has increased|
|The poorest growing environments have the least vigorous creeping bentgrass |
and, therefore the highest amount of poa annua reestablishment