Rudbeckia laciniata 'Herbstsonne' AGM is a tall herbaceous perennial with an ultimate height of around 2.5m (8ft). Although it has strong stems, here at Rosemoor, we stake it just to be sure it remains upright. The daisy flowers have reflexed petals and high conical centres of green disc florets that become yellowish-brown with age. If you deadhead, the flowers will continue well into the autumn.
It's easy to grow in full sun or partial shade and likes a moderately fertile soil that is moist but well-drained. It makes an excellent cut flower and is best grown in a cottage garden or informal border.
It looks good combined with flowerheads made up of tiny flowers such as Joe Pye weed (Eupatorium). Native to North America, it's complemented by other daisy-type flowers from the same continent, such as asters or sunflowers. Dark coloured foliage and flowers contrast effectively and tall grasses also combine well as they contrast in form and add an airiness to a scheme.
In the Long Border at RHS Garden Rosemoor, we have combined R. ‘Herbstsonne’ with the red-veined leaves of Euphorbia sikkimensis AGM, the brightly coloured foliage of Miscanthus sinensis 'Strictus' AGM, harmonising Hemerocallis 'Burning Daylight' AGM and the contrasting purple-leaved Lysimachia ciliata 'Firecracker' AGM. The clipped hornbeam hedge makes a perfect backdrop and protects from damaging winds.
The bright yellow flowers make it an appropriate plant for the Hot Garden and here it jostles with yellow-leaved dogwood, Cornus alba 'Aurea' AGM, the bright yellow flowers of giant goldenrod and the graceful pink flower panicles of the grass, Miscanthus sinensis 'Ferner Osten' AGM. The purple-pink flowerheads of Joe Pye weed, Eupatorium maculatum, contrast in colour and form as does the feathery foliage of purple fennel.
Find out more about the Award of Garden Merit (AGM)
See plantsman Graham Rice's selection of 10 AGM-winning yellow daisies