The increased availability of improved turfgrass species and varieties provides an excellent opportunity to select the most well adapted turf to site conditions. Well adapted species require reduced amounts of inputs of supplemental fertilizer and pesticides, and if selected for drought tolerance, requires less water to survive and maintain playability.
It is critical to keep abreast of the latest developments in turfgrass breeding when selecting the best species and varieties. Source: Frank Rossi.
Highly specific and often less than ideal microclimate conditions challenge many superintendents. A common microclimate is a putting surface location with light deficits and restricted air movement. In these situations, limited options exist for proper turf selection, as these climates simply cannot sustain any turf without significant inputs. Typically, in northern climates, these adverse site conditions lead to increases in weedy species such as annual bluegrass.
Choosing the Right Grass
The perennial nature of golf turf implies that when you do establish or renovate a new turf area it is critical to choose a well adapted species and variety. Of course, putting surfaces are unique growing environments, but larger areas such as fairways could have grasses adapted to reduced nutrient levels and increased traffic tolerance, potentially reducing the nutrient loading. This is an important BMP for nutrient management. Additionally, natural areas that serve as landscape BMPs also require careful attention to finding a well adapted species. Certain grasses adapted to low inputs, reduced mowing, even submersion tolerance could be part of the selection criteria. Ultimately, it is vital to start out with a well adapted species that will thrive, meet the functional and visual quality expectations, and be sustained using BMPs.
Over time, annual bluegrass becomes the dominant species in turf. This invasiveness is a result of the highly adaptive and prolific reproductive capacity of annual bluegrass that favors its competitive ability over other cool season turfgrass. Therefore, regular surface disruption when desirable turf is not actively growing selects for the invasive annual bluegrass. Read more
Eventually, every course faces the choice to renovate or manage, invariably when there is catastrophic failure. Renovation eradicates and then manages to exclude annual bluegrass, hopefully with proper site modifications to allow perennial species to thrive. Conversely, others choose simply to manage the annual bluegrass type that has colonized the location. This is a “pay me now or pay me later” situation where management is less disruptive, but the inputs required to sustain adequate turf are costly.
Research shows that annual bluegrass requires significantly more inputs to provide acceptable quality golf turf, especially on putting greens, than more perennial species such as bentgrass or fescues.
Annual bluegrass invasion into existing bentgrass putting green. Over time, the continued surface disruption and shift in maintenance will lead to increasing populations of this invasive species. Source: Frank Rossi.
Annual bluegrass is very susceptible to winter damage, especially from ice accumulation. Note the live bentgrass amongst the dead annual bluegrass. As the turf thins, the potential for off-site movement of inputs increases. Source: Frank Rossi.
Annual Bluegrass and Water Quality
For water quality protection, the answer seems obvious that the less annual bluegrass being managed, the fewer inputs required, and the lower the risk to water quality. While this solution may not be as practical on putting surfaces, the putting surfaces comprise less than 10% of the managed turf. It is fairway, rough, and tee areas where annual bluegrass challenge water quality preservation with large tracts of land being treated to sustain a weedy species.