“Mottled Look”

As referred to in our initial post (Welcome/Status Report), during our putting surface transition many of greens have a “mottled” look. We are going to dive a little bit deeper into this.

#12 putting surface                                                                         #12 putting surface labeled

As you can see in the above photos, the current putting green turf stand includes many different grass types. They are labeled and highlighted on the right:

• Fine Fescue – Chewings and Creeping Red Fescue were in the original planting mix. Until the second half of 2015, greens were regularly overseeded with fescue.
• Annual Bluegrass (Annual Biotype) – this is the annual bluegrass (aka “Poa”) biotype that initially encroaches turf stands in the PNW. In the early stages of encroachment, annual types tend to be coarse-textured and seed prolifically.  These biotypes eventually transition to perennial biotypes which dominate older PNW putting surfaces.
• Annual Bluegrass (Perennial Biotype) – perennial biotypes of “Poa” are typically fine-textured and, in some cases, seed production is minimal and/or have less impact on ball roll. Another trait is certain strains tend to grow lower than other grass types and spread laterally. There are multiple perennial biotypes in the PNW.
• Colonial Bentgrass – This was in the original planting mix with Fescue and has been used in overseeding. Because it tolerates lower mowing heights, it works well as a component in the putting greens during the transition to “Poa.”

So, you might ask, why not just seed the putting greens with perennial biotypes of “Poa?” Unfortunately, the commercial availability of seed for these biotypes is very limited.  We have been using the one commercially available Annual Bluegrass seed (‘Two-Putt’ Creeping Bluegrass) during the transition.

That leaves us installing sod as the only other option for a more rapid transition. There is one source for putting green quality perennial “Poa” sod, which we have been using since late 2016.  We will be installing more of this sod on #7 green in September.

Regardless of grass types, our goals are to provide a) smooth putting surfaces, b) maintain firmness that can be found on links courses and c) consistent green speeds throughout all greens.  All of these are driven by our cultural inputs (mowing, rolling, grooming, fertility, aeration, topdressing, growth regulators, irrigation, etc.).  We have adjusted each of our cultural practices to favor “Poa” and its evolution from annual to perennial biotypes.

More to come!