Coreopsis grandiflora (Compositae) The compact plants reach 60 cm tall and wide. Lanceolate leaves are up to 10 cm long by 2.5 cm wide and medium to dark green. They will bloom all summer long with showy 5cm across semi-double heads of a yellow colour. Date of harvest : December 2010. locality : Ex Hort. Sowing : Seed germinate readily at 70? F (21? C).