Plant Select 2014. 4" tall x 15" wide. A superb native groundcover plant for slopes and dry areas, Zinnia grandiflora ‘Gold on Blue’ (Gold on Blue Prairie Zinnia) is an unusually large-growing form of Prairie Zinnia. Blooming in summer with golden-yellow daisies, the foliage develops a distinct blue tinge. Spreading by suckers, ‘Gold on Blue’ is a vigorous spreader, so plant it among larger, taller plants.