Threadleaf coreopsis (also commonly called whorled coreopsis) is a rhizomatous perennial which typically grows in dense, bushy clumps to 1-3' tall. Flowers appear singly in loose clusters in a lengthy late spring to late summer bloom period which sometimes extends to first frost. Plants in the genus Coreopsis are sometimes commonly called tickseed in reference to the resemblance of the seeds to ticks.