‘Red Hot Vanilla’ is more winter hardy than some of the previous thread leaf varieties of Coreopsis, and the cream flowers with dramatic red centers cover the plant from early to late summer. With its rounded compact habit, Red Hot Vanilla is easily at home in a formal garden as well as a wild one, and looks exceptional when planted en masse.. Mature Size: 20-26″ x 15-18″ after 3 years. Full Sun (6+ Hours), Morning Sun Afternoon Shade.