Turfgrass at Okinawa

After last week’s Asian Amateur Championship at Kasumigaseki CC, I came to Okinawa for a meeting of the Okinawa Greenkeeper’s Association. The meeting was held at Unimat Okinawa Golf Club and I spoke about optimizing playing conditions for warm-season turf, the challenges of overseeding bermudagrass greens in the climate of Okinawa, and on my experiences working at the Masters, US Open, and Open Championship this year.

Okinawa has eighteen golf courses and they use a range of grasses, from A to Z, Axonopus to Zoysia, as Dr. Hikaru Akamine from University of the Ryukus told me. I met him yesterday and he provided me with a reprint of an intriguing paper he wrote about morphological characteristics of Zoysia tenuifolia and how to distinguish it from Zoysia matrella. This is something I am quite interested in, as the standard classification involves leaf widths but is not useful in practice. Why? Z. tenuifolia tends to be more narrow-leaved while Z. matrella tends to have a slightly wider leaf, but there actually is a lot of overlap in leaf width with some Z. matrella types having very narrow leaf blades. Dr. Akamine’s paper shows that folded leaves in the bud are Z. tenuifolia and rolled leaves in the bud are Z. matrella.

There are many excellent zoysias here, and that is what I see in the lawns around the pool as I look out from my room this evening. But in visits to two golf courses today, I also saw bermudagrass, carpetgrass, St. Augustinegrass, and centipedegrass in addition to the ubiquitous zoysia. And there is one golf course here with bentgrass greens, while at least two others are planted to seashore paspalum.

I suggested to the greenkeepers here that they establish more evaluation plots on their courses. I think that seashore paspalum may be particularly good on putting greens in the climate of Okinawa, and I made some suggestions in a second seminar today about the management of ultradwarf bermudagrass greens. You will find some dramatic golf courses and a wide range of grasses on this small island.