Grow your very own summer sunflower fields! One of the larger sunflower varieties, the Skyscraper Sunflower grows up to 12 ft. tall—and bears heavy yields of bright yellow flowers that are up to 14-in. across. Because of their height and large flowerheads, Skyscraper Sunflowers benefit from staking. This is a great variety to grow near a fence or garage. Bees will love the flowers that bloom throughout the summer. You'll have plenty of seeds for roasting—or leave in the garden so birds can come and feast. 75 DAYS.