This grower is sure of this plant identification.
Threadleaf coreopsis, Tickseed
Coreopsis verticillata (Threadleaf coreopsis). This is a bushy spreading perennial clump which is native to North America. The flowers are profuse and yellow and will bloom in the summer. The leaves are dark green and pinnate.
They are fully to frost hardy, and will need full sun with fertile, well drained soil.
Border, cutting bed, naturaliser. Summer/Autumn interest. Suitable for coastal conditions.