The new A and G series bentgrass cultivars and DW-184 creeping bluegrass (Poa annua var. reptans) are more aggressive than their greens predecessor, Penncross, which creates a dilemma for golf course superintendents: Is more aggressive thatch management needed with the new cultivars? These new turfgrasses for golf greens can produce in excess of 2000 shoots/dm² compared to less than 1500 shoots/dm² for Penncross. The increased shoot density has led to concerns about an accompanying increase in thatch development and the prevention of topdressing materials filtering down below the canopy. Because creeping bluegrass is new to the cultivation side of the industry instead of something needing eradicating, documented management protocol is needed.

Researchers at the University of Wisconsin used a three-year study to help sort out optimum cultivation and topdressing practices. The study looked at aeration (once vs. four times per year) and topdressing/verticutting combinations (applied monthly or biweekly, with verticutting or without) and how they affect thatch development, topdressing removal and turfgrass quality. Using A-4, G-2 and Penncross bentgrasses and DW-184 creeping bluegrass, they put cultural management to the test.

They found thatch development to be higher in the A and G bentgrasses, but thatch control was similar to the Penncross and creeping bluegrass. Topdressing was the most effective method of thatch control and topdressing with verticutting showed the greatest reduction in removing topdressing material. The consistent dilution of thatch with topdressing material worked wonders in controlling thatch. There were no significant differences in thatch control between aeration and verticutting frequency. Cultivation techniques may affect other soil/turf qualities such as bulk density and infiltration rate - these were not looked at with this study.

Overall, cultural management for A-4 and G-2 bentgrasses should not vary widely from Penncross or DW-184 creeping bluegrass.