Nothing says summer quite like brilliant yellow daisy-like flowers, and that is what coreopsis 'Zagreb' is all about. Threadleaf coreopsis earns its nickname from its fine, feathery green foliage, giving it a fresh airy look under all those beautiful yellow blooms. This is definitely a sun-lover and performs well all summer; however, you can give it a light haircut in late summer to encourage one more flush of blooms before the temps drop.