This isn’t your mother’s Lowertown — nor is it the one Egg founder Matt Peiken moved to 12 years ago (he has since fled across the river to Minneapolis). The arts and culture are thriving in Lowertown, and the latest symbol of that is Concrete & Grass, which filled Mears Park with more musical variety than you’re likely to find in another local festival. 3-Minute Egg went to the third and final day of the third annual fest, this past weekend, and caught sets from Jelloslave, the Flatwheelers, Heiruspecs and the Saint Paul Chamber Orchestra.