PENNSYLVANIA TURFGRASS: David R. Huff, Ph.D., Professor, Penn State University

Even in the current era of elaborate conspiracy theories and stories of bird-like aliens, and others having secret military bases on the dark side of the moon, it’s hard to imagine anything as contentious as Poa annua in today’s golf industry. For example, contrary to a recent survey that claims Poa annua is the golf industry’s third-most popular (aka abundant) turfgrass species (Golf Course Environmental Profile, 2017), most superintendents are committed to eradicating it. Conversely, despite Poa annua being the only turfgrass species in use that lacks any improved varieties and exists solely as local land races, a majority of the best golf courses strive to propagate it (https://www.top100golfcourses.com). For the past 100 years, the controversial ‘friend vs foe’ status of Poa annua has heavily favored its eradication. However, it is now time to begin exploring the best management practices (BMPs) for its propagation. That’s because soon a commercial seed source of improved varieties that have been specifically bred for use on greens and fairways will become available (see Huff, 2022). In this article, we’ll explore the grow-in of a 2022 golf course evaluation trial of Poa annua on greens and fairways.

Testing Trials

One of the first steps that needs to be undertaken during the release of any new variety of turfgrass is its evaluation at different locations, which I initiated with experimental varieties from my Penn State Poa annua breeding program back in the early 2000’s (see for example, Mitra et al., 2009). I first trialed my experimental Poa annua varieties back in 2002 at Apawamis GC, Rye, NY (Fig. 1). Superintendent Bill Purdy had just harvested sod from three of his Poa greens to enlarge his remaining 15 Poa greens, and then used Penn State Poa seed to reseed his three bare greens. Establishment went well and his members were thrilled with the results. However, about 10 years later, we realized that the problem with Poa annua commercialization was not varietal development but rather varietal instability during seed production, and it took another seven years of research after that to solve the problem. During those intervening years, Superintendent, Michael McCormick (Apawamis superintendent from 2016-2022; currently, superintendent at Oakmont CC, PA) observed that those Penn Poa greens were more tolerant of biotic and abiotic stress and used less water than the other 15 greens of the local Poa. Now that we’ve solved the commercial seed production problem and are able to produce seed of phenotypically stable Poa annua, I’ve organized a new evaluation trial of the final commercial seed product at six trial locations which includes golf courses on the East & West Coasts and from the Northern to Southern Appalachian Mountains (Fig 2.).

This new 2022 Poa annua trial has now been established at five of the six trial locations, with the Cypress Point Club (CA) trial (delayed due to weather and events) to be established in July 2023. The following are some early observations of establishment and grow-in of Poa annua at these sites.

Seeding Rates

Early in the breeding program there was never enough seed to plant the areas we needed to establish, so we had to stretch seedings to their maximum lowest rates in order to plant the largest possible sized areas we could. As such, we’ve planted greens as low as 0.3lb/K, but those areas took an entire growing season to properly fill in. We eventually settled on a 1lb/K seeding rate which is a relatively low seeding rate for Poa, but after a fall planting, it gave us an opportunity to watch the experimental varieties complete their grow-in during the following spring and we had full stands to evaluate over their first summer. Personally, I prefer low seeding rates because it results in strong,