As far as I know, there are no examples of Pacific Northwest (and probably northern California, too) courses which have managed to fend off an eventual transition to Poa annua.
The best example of maintaining bentgrass greens for a long time, that I'm aware of, is Stanford University GC, where superintendent Ken Williams does not conduct typical aerations. I think he may aerate with small tines, or do that water injection style of aerations. But I don't think he takes plugs out of the greens. After about 20 years, they are still only 1-2% Poa, based on my last round there.
Never been to Bandon. I've played 3-4 rounds on greens with significant Poa creep. John, in your opinion, what's better for play at Bandon: completely poa greens or fescue with poa creep? Hope the question makes sense.
Hi Ryan,
In my experience, greens in mid-transition are less enjoyable to play.
At my home club, Pumpkin Ridge west of Portland, Oregon, it took about 8 years for Poa annua to establish a significant percentage of the greens. Maybe 10-20% or so. At that point, management said they were giving up trying to keep it out, and changed maintenance practices to allow it to flourish. For the next 5-7 years, the greens were relatively slow, uneven and bumpy. After 15 years, the greens were 75-95% Poa, and evolving into a finer putting surface. Poa annua adapts to a low mowing environment, as described by this key USGA article on the subject:
http://www2.gcsaa.org/gcm/2006/dec/pdfs/073-088_dec06.pdfNow 23 years old, our Poa annua at Pumpkin Ridge have largely evolved into a tight turf well suited to the environment, which allows faster green speeds than the original Penncross bentgrass surface. They are very smooth once again, after several years of bumpiness.
So far at Bandon, Bandon Dunes is 16-17 years old, and the Poa transition is largely complete. Pacific Dunes's greens have been bumpy the last few years, but should smooth out soon. Bandon Trails is a few years behind, with a Poa infestation on the greens nearing that 10-20% mark which begins the difficult transition period. Old Macdonald is still almost 100% fescue, a fantastic surface to play and putt on. Enjoy it while you can.
In my opinion, the fairways take a little longer to make the Poa transition, as player traffic is better dispersed.
The big question is whether the Poa annua grass will make a reasonable surface for the fast, bouncy conditions that some of us covet. I think it's clear that Poa annua will play a bit softer than the planted fescues, but I also think Poa annua will have some advantages as the dominant native grass. At this point I would appreciate someone with professional experience to add anything more.