Bentgrass Removal Trial

Last week we sprayed out some of the bentgrass that is in the fairways of Lake 5, Mountain 4, 5, 8 and Canyon 2 approach.  We are trying two different rates and two different products.  In the meantime, the bentgrass will have a bleached appearance. After the second application on the 20th we will verticut multiple times, shave the areas down with a low height of cut mower, seed and topdress.  I hope to have the process dialed in for 2018 and we can remove the bentgrass that has contaminated the fairways on a much larger scale.

Why would I want to remove the bentgrass?  Bentgrass thatch accumulation is very fast and that thatch holds onto water like a sponge.  For the player, this leads to a plugged ball.  For the maintenance department, we can't get water past the top inch and some products we apply need to get into the soil to work.

Roundup on the left with the crabgrass still green on the right.

57 Shades of Green

Unless you are playing at Augusta or some other ultra high end course, you are going to see multiple shades of green on a course.  In the superintendent world, we call this the Heinz 57 blend when we are referring to fairways, roughs, and tees.  As Cinnabar ages, we certainly have our version of Heinz 57.  Predominantly you'll see dark green and that is the ryegrass; the desired species here.  We also have bermudagrass, bentgrass, dallis grass, Poa annua, kikuya grass, crab grass, and goose grass.  Of all the grasses listed, we currently trying to selectively kill all of them other than ryegrass in the fairways and bentgrass in the greens.  Unfortunately I've succeeded at killing those too at times.  

Yellowing grass is kikuya grass, silver green is bentgass, dark green is rye 

Silvery green bentgrass and yellow dying Poa annua

Greens Coring

With greens coring (as they say in New Zealand) here, our Marketing Director, Cecilia Ashley, asked if I had anything on our blog about why we core the greens.  I hadn’t yet and wasn’t planning on it as I tell the same story every year.  We’re removing thatch, getting more air porosity and better water movement.  The same boring thing you hear every year and you don’t feel any better about the process.  It’s still holes, sand, bumpy, and slow. 

    

So what if I put it this way.  For the last 18 years, you have arguably played the best greens in the South Bay, if not some of the best in Northern California.  Do you remember the time you sank that 25 footer for a skin?  Do you remember the first time you went under 80 because you rolled in a smooth 5 footer to finish on number 18?  Do you recall the time you had your friends over from the best private club in the Bay Area wishing their greens were like Cinnabar’s?  Sure there is a great deal of skill involved, but the first thing to be blamed for missing out on 79 isn’t going to be the putter?   

The greens at Cinnabar Hills are some of the best in California because of the process and yes, unfortunately for 6 weeks a year, it’s an inconvenience.  I’m told a colonoscopy is an inconvenience too, but it’s part of the process as we age.  Greens aeration can’t be that bad… or can it?

P.S.

For those who see past the sand.

1.  Fertilize the greens one week prior to get them growing
2.  Core greens with 0.5" coring tine on 1.5" centers
3.  Remove 5 yards of organic matter and soil from every green
4.  Clean excess sand off of surface
5.  Apply gypsum
6.  Apply sand at 16 tons per acre
7.  Deep tine aerate with 5/16" solid tine
8.  Drag sand into holes with metal mat
9.  Blow sand off of greens
10.Seed greens with bentgrass
11.Drag sand again with coco  mat
12.Roll greens
13.Change cup
14. Fertilize with organic fertilizer next day
15. First cut 3 days prior
16. Additional sand to top off holes the next week
17. Apply wetting agent to naturally hydrophobic sand
18.Watch them grow
19. Enjoy great greens until we aerate again in August

Seems so easy now that I’ve written it down.  

Ghostly Bentgrass

Bentgrass after 1 of 3 applications

Over the past few weeks, I have been spraying a product called Tenacity on the 3rd and 7th hole of the lake course.  Tenacity is a selective herbicide labeled for many weeds, but in our case, I am going after the bentgrass that is taking over our ryegrass fairways.  When the course was seeded in 1998, there was 10% colonial bentgrass in the seed blend and we have many large areas of bentgrass in our fairways.  Looking at the photos of what is dead and what is healthy, you have to be amazed at the chemistry to be so selective.  It also amazes me that it only takes 5 oz/ A to take care of business.

After three applications, I am pretty sure the bentgrass is toast.  It is really cool how the bentgrass turns stark white after the active ingredient begins to take effect.  This is because the active stops photosynthesis.  We will be reseeding in the next week with ryegrass.  The experiment isn't so much as to whether the product works now, but what will happen next year after the ryegrass has established.  If the bentgrass comes back quickly than I may as well spend less money on round up and fusilade.