This grower is sure of this plant identification.
In the photo, Zagreb is the yellow flower at the front of the border.
Threadleaf coreopsis, Tickseed
Coreopsis verticillata ‘Zagreb’ (Threadleaf coreopsis). Has golden yellow flowerheads, and is drought resistant.
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.
Italics = data drawn from parent genus or speciesView Full Plant Finder Record