Why Are Our Greens So Patchy and Bumpy? February 4, 2015

Believe it or not, all of the grasses in this picture are Poa annua. There are often many strains (biotypes) of Poa annua in older greens. This diversity can result in a patchwork appearance and occasionally, bumpy putting greens. The picture is from research plots where scientists evaluate different biotypes for traits such as disease resistance, drought tolerance, etc.

Not surprisingly, golfers don’t spend a lot of time discussing the genetic aspects of the grasses that make up the greens on which they play the game. It is true that most golfers know whether they putt on bentgrass, bermudagrass, paspalum, zoysiagrass or Poa annua but their eyes quickly begin to glass over when superintendents and agronomists try to explain the intricacies of managing these plants. Fair enough; you come to the course to play golf not study botany. But (you probably knew a “but” was coming), if you can spare a minute or two there are a couple of facts regarding these grasses that impact your game so it is worth reading on.

While it is correct to refer to your greens collectively as bentgrass, bermudagrass, etc., you should realize that your greens are very likely made up of many strains (biotypes) of grasses. In other words, there are probably many types of bentgrass in your bentgrass greens, bermudagrass in your bermudagrass greens, etc. So how does this impact your game?

During certain times of the year, the different strains of grass in your greens will look different from one another. Older greens might look like a patchwork quilt. Although the surface may be perfectly smooth, the different colors might make you think ball roll is impacted. For most greens, these patches have little or no impact on your putting. However, there is an exception.  Poa annua greens often are made up of a very large number of different biotypes and they can look and act differently throughout the year and even throughout the day. Some of the Poa annua types produce tremendous quantities of seed in the spring. Others might be more prone to disease problems. Still others might grow slowly while its cousin in the next patch over might grow rapidly. While all these different growth characteristics might not be obvious immediately after the morning mowing, they can impact putting quality as the day wears on. For these reasons, Poa annua greens are often bumpy in the late afternoon hours.

Since 1921 the golf course maintenance industry has worked hard to overcome many of the disadvantages of Poa annua. As a result, many courses across the country with Poa annua greens offer putting quality that rivals the best of the other grasses utilized on greens. The USGA continues to fund research to improve grasses of all varieties to improve your enjoyment of the game and to meet the environmental and economic challenges that lie ahead.

Click here If you would like to learn more about Poa annua.

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