Vermont continues to provide an extreme test site for these grasses on the cold end of the spectrum. Last winter (2013-14) had a severe ice storm (1in. or more on surfaces), but ground temperatures remained fairly average. This winter (2014-15) may prove a serious hardiness test, with 14 days in January soil temps. below 28F, and 6 at 25F or below– the coldest temperatures in 25 years of recording in this zone. This past summer (2014) also was cooler than normal, with only 4 days 90F or above, the highest being 93F, and no days in August at 90F or above. So while the Panicum grew more than the previous year, with several decent performers (Dewey Blue, Northwind, Prairie Sky, Shenandoah, Thundercloud), overall many still had quite a bit of variability and weak growth. The bluestems were fairly uniform among a cultivar, but cultivars varied widely in vigor, only a couple being really acceptable, very uniform and typical (Blaze, Blue Heaven with this by far the best with excellent fall color).
National Grass Trials 