Now You Seed It, Now You Don’t May 23, 2011 By Larry Gilhuly

Spring is the time of year when all plants like to return to normal and strut their stuff.  In the world of turfgrass, no grass seems to enjoy the spring more than the hated/loved Poa annua.  In the Pacific Northwest (commonly referred to as Poa annua central) this grass has received its signal from nature with full bloom occurring all over the region.  However, a recent visit to Palouse Ridge Golf Course at Washington State University (WSU) shows at least one very impressive method to eliminate the seeds and dramatically reduce the overall Poa annua populations on fairways.

Researchers at WSU have now completed two years of research on a plot of Kentucky bluegrass fairway that was inundated with Poa annua.  As can be noted in the photo, various combinations of mesotrione (Tenacity), ethofumesate (Prograss), bispyribac-sodium (Velocity) and prodiamine (Barricade) are producing very good results, and not just with Poa annua.  Todd Lupkes, CGCS, reports that this combination also has been very effective in removing most broadleaf weeds and several persistent grassy weeds.  For an outstanding PowerPoint presentation on this research at WSU, see the 2010 Turfgrass Research Highlights  to view all of the results with these various products.  For those interested in reducing this grass from their fairways, tees or roughs, the information and results are very impressive.  For those not so inclined, read on.

Although the removal of Poa annua is not an option for most golf courses in the Pacific Northwest, the troublesome issue of seedheads on greens has once again hit with a vengeance.  Chemical control has helped by using Proxy, but the perpetual rain that seemed to never end in March, April and early May has lessened the results with this material this year.  In its place, many superintendents are getting good results with the old-time combination of light vertical mowing and brushing.  Both passive and power brush units are producing acceptable results at many courses, with various brushes beginning to make a comeback to battle this issue.  For more on this topic, please see Bring Back Brushing by Brian Whitlark in the March 25, 2011 Green Section Record.

As a final note, remember that Poa annua seedheads will not last forever, and we will be in the middle of the summer in the blink of an eye.  Then we can talk about bentgrass seed.


Source:  Larry Gilhuly,