Our biggest challenge and nemesis at HCC is the contamination of bentgrass, Poa annua and rough bluegrass in our roughs. What can we do about it and why doesn't anything seem to work?
Bentgrass is the primary culprit as opposed to Poa annua that everyone thinks. Our cool, wet climate allows these grasses to thrive compared to the drought, heat preferring Kentucky Bluegrass (KBG) which is our desirable turf for roughs. In spring, we loose a lot of ground when the bentgrasses start growing at cooler temperatures compared to the KBG. In fact, KBG isn't really actively growing until late May while the bentgrasses have been creeping along for 2 months!
There is a chemical called Tenacity, labeled to remove bentgrass from KBG. It turns the bentgrass a bleached white color. I have used it several times at HCC. However, it only seems to control about 70% of the bentgrasses in the rough. The damage it causes creates a look that is unacceptable to golfers. Its very ugly!
We allocate a small amount of funds in the operating budget to replace 2 acres of sod per year in our roughs. Keep in mind, we have over 35 acres of rough at HCC. As you know, after about 3 years after resodding, the bentgrass is right back. Our look of clean, well defined rough is short lived. What are our solutions?
1. Ideally, fumigating the rough prior to resodding would be the ultimate solution. Using Methyl Bromide (soon to be taken away forever by the EPA) we could sterilize the soil, eliminating any chance of bentgrass coming back through.
2. Spraying the roughs to be resodding with Round up prior would also be a good solution. By making 2 or 3 applications, we would ensure the bentgrass would die. Therefore, there would be no stolons remaining that the sodcutter missed. That sounds easy, right? Well, we would need to start in September because in order for roundup to be effective, it needs to be actively growing.. I doubt the membership would support seeing dead grass on 2 or 3 holes. In addition, there is the major risk of tracking the round up to other areas of the course.
We have used and tried several other chemistries with some minor success. However, with a course as old as HCC that has a tremendous seed bank in the soil, there is very little that can be done without taking drastic measures as discussed above. We continue to resod the worst areas and realize this is part of the price we pay for living in such a beautiful area (a temperate rainforest)!