Butterflies enjoy the flowers and birds love the seeds. Coreopsis is easy to grow from seed and all manner of varieties are available as plants.
They love heat and sun and succeed in dry locations. Perennial varieties are cold hardy to zone 5. Annual varieties re-seed and return but not enough to become pests - the birds eat too many of the seeds for that.
Coreopsis comes in tall, short and groundcover. They all bloom profusely and make a sweet cut-flower bouquet. The bright yellow native one above is about 4-feet tall.
Like pink flowers? Coreopsis American Dream is a thread leaf variety - pink flowers with yellow centers. The 1993 flower of the year in the Netherlands.
Coreopsis Dream Catcher is another pink flowering variety. 14-18 inches tall and 18-inches tall
Coreopsis Autumn Blush has dark centered peach colored flowers on 24 by 24 inch plants.
Coreopsis lanceolata Baby Sun is only 16 by 16 at maturity - bright yellow flowers.
Cold hardy in zones 3 to 9, compact plant and flowers - good for containers.
At the other end of the spectrum is Coreopsis Creme Brule. The plant grows to almost 2-feet tall and 2.5 feet wide.