Gaillardia (Gaillardia aristata) Gaillardias send up their large flowers (up to 4 cm across) from a clump of hairy leaves, on stalks that may reach to 40 cm. They bloom in late June through mid-July. This is another native plant that is familiar to most gardeners. Horticultural gaillardias are mostly a related species, also originating on the prairies, Gaillardia pulchella.