Create a hot splash in your garden this summer. Threadleaf coreopsis (Coreopsis verticillata) ‘Route 66’ is a new selection by Itsaul Nursery in Atlanta, Georgia (USDA zone 4 to 9). Coreopsis ‘Route 66’ originated in Pennsylvania (zone 5). Perennial gardeners have been planting yellow- flowered ‘Moonbeam’ and ‘Zagreb’ cultivars for over a quarter of a […]