Tuesday, September 23, 2014

Rough at Biltmore

The rough at Biltmore is always a challenge.  One type of grass that we have never planted but has dominated the peat ground is Poa trivialis or commonly called Roughstalk Bluegrass.  It most likely came to Biltmore as a contaminate of grass seed, this was very common in the early days of seed production, but not as much now.  This should not be confused with Kentucky Bluegrass or Poa annua, all three are very different grasses.

Poa trivialis (Roughstalk Bluegrass) likes: shady, wet areas.  When it gets hot, goes dormant or to the layman "dies" and lays flat in a matted dead appearance.  It looks dead, but it is not.  It is just waiting for things to cool down/ and get wet.  It can tolerate sunny areas, but does best in shade.  It is very thatchy because it spreads by stolons making it difficult to advance a shot from.  It can also not handle wear or traffic like Bluegrass.

Poa pratensis (Kentucky Bluegrass) likes: sunny, well drained areas.  It can handle very hot weather and can also go dormant during dry times but when it does, stays standing up.  Much easier to advance a shot from - a bunch type grass.

As their scientific name implies, they are both in the same Genus but have very different "likes" and growth habits.  Poa trivialis is a weed of golf courses (along with it's cousin Poa annua) and both are never intended to be planted.

Control is difficult, as Poa trivialis is a prolific seeder and can grow back from its stolons.  In the past we have found some success in roto tilling the areas and seeding with our "Biltmore Blend" of Bluegrass seed.  Our blend was specifically picked for traits that worked best for us - dense, disease resistant, aggressive (to out compete the Poa trivialis), wear tolerant, able to handle some shade, and dark in color with early spring green up.  Unfortunately there is no one best cultivar, so we created a blend of several cultivars with attributives best fitting our situation - some are better in shade, some are better in wear tolerance, diseases, etc.  The idea is whichever variety is best suited for the environment, it will survive.

Several yeas ago we tested a product call Tenacity for the control of Poa in the rough.  We found good results and then did a course wide application.  This was not well received by the membership due to the extent of the control (dead Poa).  However, after the voids filled in with the Biltmore Blend complaints about the rough dropped considerably.  We did not treat under trees because areas were best suited for the Poa and the Bluegrass would not be able to compete.  As trees are removed these large patches of Poa trivialis are exposed to sun and go "dead" during stressful times.  The best solution is to rototill these areas in late August and seed with our Biltmore Blend of Bluegrass.  Seeding in late August is ideal time of year and these areas typically re-open to play by October.

For more information check these links:

Ohio State - Poa trivialis
GCSAA - Poa trivialis
Sugar Creek Golf Course Blog
Wikipedia Poa trivialis

Poa trivialis still green under the tree.  Most likely next year the Poa will go dormant during a hot period, typically late August.

This old tree stump is located between #11 and #14.  The stump is in the back of the picture.  On the North side of the tree the Poa trivialis has gone dormant, with a few patches of Bluegrass still green. Look closely and you can see the new Bluegrass seed coming up.  Most likely when the Poa trivialis breaks dormancy and comes back to life it will overtake the new seedlings.  The ideal way would be to renovate this area and then seed.

This Bluegrass covered stump (between #2 and #9) with Poa trivialis thinning on the North side of the tree.

This area (right of #13 near the green) was seeded last fall to the Biltmore Blend of Kentucky Bluegrass.  Small patches of Poa trivialis is trying to come back (light yellow), but the Bluegrass does have the upper hand as of now.  At these levels, chemical treatment would be very effective in keeping this area clean of Poa trivialis.