Team asters and rudbeckias for a dazzling daisy display that will last until the frosts, says Helen Billiald
Rudbeckia is one of the shining stars of autumn, leading us merrily into a season of mists, bonfires and heavy dews. ‘Goldsturm’ is one of the brightest cultivars, its large, golden-yellow, daisy-like flowers blooming from August to the frosts. It’s partnered here with Michaelmas daisies – another of autumn’s calling cards – and lavender-blue ‘Mönch’ is one of the best. Vigorous and disease resistant, it starts flowering in late July and is still going in October, its soft flowers appearing to hover in the low light of dusk.
These two both hold an RHS Award of Garden Merit and are equally floriferous, the golden rudbeckia petals picking up on the yellow centres of the asters behind. The duo is joined by a few lipstick-bright hesperantha spikes to keep everything on its toes; a seasonal match made in heaven.
YOU WILL NEED:
Aster frikartii ‘Mönch’ Deservedly popular aster with masses of lavender-blue, yellow-eyed flowers on branching stems from late July-Oct. H90cm (3ft) S45cm (18in)
Pennisetum alopecuroides ‘Hameln’ Tiny Chinese fountain grass with bristly pink-tinged flowers above wiry foliage. Leaves turn yellow in autumn. Likes well-drained soil. Deciduous. H and S90cm (3ft)
Hesperantha coccinea ‘Oregon Sunset’ River lilies (formerly schizostylis) bear red, pink or white flowers Sept-Nov. This cultivar has star-shaped salmon-red flowers. H60cm (2ft) S30cm (12in)
Hakonechloa macra ‘Aureola’ Golden mounds of arching green-striped foliage that’s tinged copper-red in autumn and ripples in the wind. Deciduous. H45cm (18in) S60cm (2ft)
Rudbeckia fulgida sullivantii ‘Goldsturm’ Dependable rudbeckia with rich yellow flowers and raised central cone, flowering July-frosts. H60cm (2ft) S45cm (18in)
HOW TO PLANT THEM: These plants are at their best in a sunny site on humus-rich but well-drained soil. They like moisture at their roots during the growing season but loath prolonged winter wet, so improve soil with plenty of well-rotted organic matter then add a thick mulch annually. Before planting, break up compacted ground and remove any perennial weeds. Keep an eye out for any fragments resprouting in spring.
1. Establish the asters and rudbeckias Establish these two border stars in spring as the ground begins to warm and new growth is showing. Dig a hole twice as wide and slightly deeper than each container, mix in extra organic matter to the planting hole and settle the plant with the top of its rootball just below the soil surface. Gently firm the soil back around its roots and water deeply. Thanks to its parentage, ‘Mönch’ has the capacity to cope with poorer, drier ground than many asters, but gives the best show on moisture-retaining fertile soil.
Staking isn’t essential for either of these herbaceous perennials and the aster’s gently leaning habit is part of its charm. However, you can add some low, woven supports to keep it off paths.
Cut the aster back to ground level once it has finished flowering, but let the rudbeckia stand as winter structure, tidying stems away as they start to collapse.
Both plants will bulk up quickly and are best divided after three years to keep them vigorous. Divide the aster in spring just as new growth begins; the rudbeckia can be split in autumn or spring. Replant the young outer sections into soil that has been improved with extra organic matter.
2. Add the hesperantha This rhizomatous perennial loves a moist but well-drained soil; you can even grow them as marginals around a pond. Plant in spring once the ground has begun to warm and keep watering to settle them, especially in dry summer spells.
The tall flowers have a tendency to topple so plant them back from the border’s edge so neighbouring plants can prop them up. In mild areas, flowers may appear until Christmas, if you keep deadheading; the foliage is semi-evergreen in a sheltered spot. Divide in spring every two to three years. A dry winter mulch offers extra protection.
3. Finish with the grasses The floral fireworks of asters and rudbeckia go brilliantly with the narrow leaves of grasses. Hakonechloa forms a low cascade that sits well at the front of the border. Despite their elegant posing, these hardy deciduous plants will take some shade, but the foliage colour won’t be as bright. They’re rhizomatous, but spread only slowly. Split larger clumps in spring as you clear away the dead leaves.
The pennisetum isn’t quite as hardy, preferring temperatures not to drop below -5C (23F) in winter. Establish new plants in spring, adding extra grit and compost to the planting hole to give them the well-drained ground they prefer. Try to position them where their bottlebrush-like flowers catch the low autumn light. In late autumn, tuck a generous mulch around plants to give them extra winter protection, leaving the flowers in place for winter structure.
In late winter to early spring cut old dead stems to ground level ready for new growth to come through. Divide established plants once new shoots appear above ground.
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