In Praise of Poa annua Greens

The greens at Oakmont Country Club, host site of this year’s U.S. Open, are the stuff of legend. They are also almost entirely Poa annua – aka annual bluegrass – and they are great! In fact, the next four U.S. Opens will be conducted at courses with predominantly Poa annua putting greens. Many of the best-known golf courses in the world have Poa annua greens – and excellent Poa annua greens at that – so, why is it that this grass has a checkered reputation for putting quality in some circles? There are some valid downsides to Poa annua greens, there are some misconceptions, and of course there is a long list of exceptions to any broad statements. Taking all that into account, in the right situations there are plenty of reasons to praise Poa annua greens.

What are the downsides of Poa annua greens?

Seedheads: One knock against Poa annua is the prolific amount of seedheads that the plant produces, mostly in the spring, but at other times of the growing season as well. Seedheads make greens look ugly and negatively impact ball roll when they emerge. In the past, reducing seedheads required carefully timed applications of growth regulators. If the optimal window was missed by three or four days, applications were ineffective. Improvements in growth regulators that reduce seedhead emergence combined with a better understanding of how to use them has significantly improved seedhead control. While timing is still important, the window for success is much wider.

Appearance: Forgetting seedheads, Poa annua greens can have a patchy appearance because many different types of the grass may be present on a single green. Poa annua evolves on greens over the decades, which means genetic differences can become visually apparent. The patchy appearance promotes a preconceived notion that Poa annua cannot possibly produce a smooth ball roll, but actually putting on the greens often tells a different story.

Misconceptions: Several televised golf events are played every year on Poa annua greens on the West Coast in January and February. Coincidentally, this is the rainy season in this region, when greens can be softer and easily affected by foot traffic. TV analysts often blame Poa annua for bumpy conditions around the hole, rather than all the golfer traffic. Spoiler alert: regardless of the type of grass, heavy foot traffic on soft greens reduces surface quality over the course of the day. Firm Poa annua greens hold up very well to routine traffic.

It’s a weed: In many instances, Poa annua is a weed! The divergence of being at one course where the goal is to eradicate Poa annua and going to another course that loves it creates confusion. This is one of the beauties of golf course maintenance. One person’s weed is another’s treasure, and both can be correct!

Maintenance: Poa annua generally has shallow roots compared to creeping bentgrass and can be challenging to maintain under stressful summer conditions. Increased summer watering may be needed at times, but we have better knowledge of managing Poa annua through stress with great success. Poa annua is also more vulnerable to certain types of winter damage than bentgrass.

Why would I want Poa annua greens after that list of downsides?

Playability: A firm, fast Poa annua green is hard to beat. Poa annua greens on many courses have evolved through decades of maintenance. The biotypes that remain often produce fewer, smaller seedheads and tolerate the rigors of daily maintenance and play to provide great surface conditions. Most of the downsides of Poa annua putting greens can be managed or eliminated with effective maintenance programs and adequate resources.

Location: In some regions and growing environments, keeping Poa annua from encroaching into creeping bentgrass greens is very challenging. More time can be spent trying to eradicate Poa annua than actually focusing on playing conditions. If resources are not available to maintain a Poa annua control program, it can quickly colonize a green. This may be a message that Poa annua is the right grass for a given location. For example, greens that experience heavy shade and traffic are often mostly Poa annua because it tolerates those stresses better than bentgrass.

The next time you play a course with Poa annua greens, know that it can be one of the best putting surfaces in the world. Preconceived notions are never a good idea when it comes to the grasses on a golf course because everything is site and management specific. Base your opinion on how the golf ball rolls rather than what you hear or think. You will realize that Poa annua may be worthy of high praise!