Doronicum orientale ‘Magnificum’ – An early-flowering Leopard’s Bane which also does quite well in partial shade, but can tolerate some sun. Yellow thin-petaled daisies are borne over bright green heart-shaped foliage from late March through to May. These are usually in prime form the same time as spring bulbs and make good companions. Grows 18-24″ high by 12-15″ wide. Zone 3.
Heliopsis helianthoides ‘Tuscan Sun’ – A dwarf Ox-Eye or False Sunflower with rich yellow daisy blooms and a golden-orange eye that are borne continuously from June to September with deadheading. It thrives in the heat of summer and definitely attracts butterflies. Excellent cut flower. Deep green foliage. Grows 15-18″ high by 20-24″ wide. Hardy to zone 3.
Hemerocallis ‘King George’ – An award winning Daylily with absolutely huge blooms (7″ across or larger) of clear yellow with a sharply contrasting red eye zone, pleated edges and a green throat. It blooms midsummer (July) over semi-evergreen strap like foliage. This bold perennial really stands out, a good choice for mixed borders. Grows 30″ high by 24″ wide. Hardy to zone 3.
Zinnia grandiflora (syn. Crassina grandiflora)- This alpine perennial is native of the American Southwest and blooms from late summer into autumn. It bears small yellow single daisies over a mound of needle-like greyish-green foliage. It does get woody like a sub-shrub and was used as a medicinal plant by the Zuni and Navajo peoples. Grows 4-6″ high by 15″ wide. Zone 4.
Inula racemosa – This tall perennial is a native of the Western Himalayas where it grows in temperate and alpine regions. It bears yellow daisies that are much favoured by the bees from July to September, after which the birds feed on the seeds. Elecampane is also an important medicinal herb used since the Middle Ages. Grows 6-7′ high by 3-4′ wide. Hardy to zone 4.