Maxwell Summer Greens Update 2020

This year golfers are seeing the benefits of the past four years. Starting in the 2017 golf season we made a commitment to convert the Pinehurst greens to more bentgrass rather than poa annua. It is a long term commitment that will continue to take time, but the benefits are endless. Bentgrass is a more consistent putting surface than poa.

Poa can be a great putting surface, but in many cases, poa can be considered a weed too. It requires so many inputs to provide a good surface and it has a lot of risk with the demands of the game today. Poa requires more water and fertilizer. It is far more susceptible to disease. Winter stress and ice build up can be lethal, where bent can survive higher stresses. Poa goes to seed at low mowing heights and wreaks havoc on putting performance in the spring and early summer. It requires a significant amount of grooming and maintenance to create a quality surface.

The reason why poa has dominated these greens surfaces for so long is due to the lack of quality drainage, over watering, too much fertilization and the desire for lower mowing heights for faster speeds. 

Is there a better way to convert? The quickest way to convert is to close for a year and remove the existing surface and re-seed with new bentgrass, similar to what was done for the putting green. Converting slowly over the years prevents closing and saves a lot of money that can be used in other areas to improve the course.

How much longer is this going to take?  There is no exact date and weather can alter the process some. We will always have poa pressure in this climate, but our goal is that in five more years we can have most greens over 90% bentgrass.

Now let's talk about color, what gives?  Today, the greens look as green as they will all season. Color is the main characteristic (not the only) on why golfers notice a change, but color has little to do with performance. You could compare it to bunker sand. Bunker sand could be a pretty white color, but if it doesn't drain well, creates a poor lie and costs a tremendous amount of money to ship to Denver, it is not a great sand.

Poa is generally a lime green color or the lighter shade you are used to seeing on greens. For years, the greens were mostly a lime green because they were predominately poa. Now that the bent is starting to take over, the golfer is taking notice. Some greens are better than others, 3,14, 15,16,17 & 18 (all greens that receive a tremendous amount of morning sun, except 16) are well over 50% bentgrass. this is a large step forward in our process. 

Greens such as 1,2,4, 7 & 13 are spotty with bentgrass populations but they are coming along. The main reasons why these greens are slower are due to shade on the greens, especially in the morning. I'm sure many of you remember the large cottonwood near 7 green, or the two large pine trees behind the first green that were removed. Morning shade, especially in the spring and fall does not allow the the proper amount of photosynthesis in the plant to ready it for stress. So when the summer or winter stress comes, the bentgrass would suffer and fail, then poa would creep in and take over. 

It looks like grass is laying on top of other plants, what causes this? Bentgrass or otherwise known as creeping bentgrass is now being noticed laying over the poa. As I mentioned in my email to the golfing membership this past weekend, part of our conversion process involves using a growth regulator to suppress the growth of poa so the bentgrass can take over. As the bent spreads across the surface, it will encroach on the patches of poa on the surface. We have been aggressive with seeding to assist with breaking up the patches and incorporating new plants into the surface.

Some bent leaf blades are thicker and can create a little bumpiness in the surface. At this point we use groomers such as brushes or vertical blades to stand some leaf blades up and mow them off to provide a more consistent surface.

What should we expect for the remainder of the season? As I mentioned earlier, color is great right now and should be that way for the rest of the season. You will continue to notice slight differences in the color of the two grasses. With the heat of the summer, the poa is less motivated to grow, so we are backing off our growth regulator rates so the poa can be strong enough to survive the summer stress. We have a lot of the golfing season left and we continue to strive for great surfaces. We will continue with grooming and giving a slight edge to the bentgrass so it can continue to thrive. Proper grooming, mowing, rolling, water, nutrients and cultural practices will continue to maintain great putting surfaces for the season.

Tree removal, adequate drainage, proper fertilizer, topdressing, aerification and grooming are all a part of good putting green maintenance. Growth regulation is another assistant in the process. In fact, with the growth regulation technology today, by the time we achieve our desired results for bentgrass populations we can explore other products that are lethal to poa to get closer to 100% bentgrass.

But why are the Pfluger greens so good?  Excellent question. I will go into more details next week in the blog about the Pfluger Course and why it has so much more bentgrass.

Stay cool.