When the seasons change, a blast of bold colour in the garden lifts the scene, and the least subtle, the most joyous is yellow. Coneflowers (Rudbeckia) are one of the best perennials for providing it: in early autumn, under grey skies, their daisy flowers shine blazing shades of Canary and gold, pairing beautifully with the flax and fawn tones of ornamental grasses.
There are 24 species of Rudbeckia, all native to North America and mostly found in the United States. They hail from a range of habitats, including prairies, which is the reason for their surge in popularity. When prairie-style planting became fashionable, garden designers employed the long-flowering, informal beauty of the rudbeckia (and other naturalistic perennials) to create meadow-inspired borders.
In the past, Native Americans used the rudbeckias of the prairies – including Rudbeckia hirta (black-eyed Susan), R. laciniata (cut-leaved coneflower), and R. triloba (brown-eyed Susan) – as medicine. The roots and dried leaves were made into tea or poultice and employed to treat a variety of illnesses, including cold, flu, infection, inflammation, earache, and snake bite. Modern studies indicate that the plant does indeed strengthen the immune system and has anti-inflammatory, antioxidant, and antimicrobial properties.
The plant was named by the Swedish botanist Carl Linnaeus, in honour of his mentor, Olof Rudbeck the Younger, a fellow botanist at Uppsala University, and his father, Olof Rudbeck the Elder, a naturalist and doctor. ‘I have chosen a noble plant in order to recall your merits and the services you have rendered,’ Linnaeus wrote in his dedication, ‘a tall one to give an idea of your stature, and I wanted it to be one which branched and which flowered and fruited freely, to show that you cultivated not only the sciences but also the humanities. Its rayed flowers will bear witness that you shone among savants like the sun among the stars.’
When rudbeckia flowers in early autumn, glowing loud shades of yellow, while much of the garden is browning, it does shine like the sun.
Which rudbeckias to grow
Of the longer-lived perennial forms, the most impactful is Rudbeckia laciniata ‘Herbstsonne’. From August to October, it is a glorious explosion of colour at the back of the border, producing flowers with green hearts and reflexed lemon-yellow petals on stems that soar to 2 metres or more. R. laciniata ‘Starcadia Razzle Dazzle’ is similar, but slightly shorter.
Another covetable tall form is the sweet coneflower (R. subtomentosa) ‘Loofahsa Wheaten Gold’, which has a classic rudbeckia look, producing large golden daisies with dark centres on 1.5-metre stems. R. maxima (the great coneflower) is perfect for a contemporary garden, having golden flowers with protruding brown cones, atop bare 1.5-metre stems, above large glaucous leaves.
In the middle of the border, R. triloba is a favourite of garden designers for creating a naturalistic look. The species has compact yellow blooms with brown centres and ‘Prairie Glow’ is a terracotta version. For the front of the border or pots, low-growing perennial choices include forms of the orange coneflower (R. fulgida), such as ‘Goldsturm’, R. f. var. deamii, and ‘Early Bird Gold’, which bear generous golden daisies with chocolate centres.
Are rudbeckias good for wildlife?
Yes. All of the perennials mentioned above have single flowers that provide food for pollinators, such as butterflies. Left as skeletal decor through late autumn and early winter, the spent flowerheads provide birds (such as goldfinches) with seeds.
Do rudbeckias come back every year?
Yes – the majority of garden rudbeckias are perennials. However, forms of Rudbeckia hirta are not reliably hardy, so they’re grown as annuals (or short-lived perennials in milder regions). The rich autumnal shades of R. hirta light up the season, and they could be grown in the kitchen garden as cut flowers. Some of the best include ‘Cherry Brandy’ (velvet red), ‘Cappuccino’ (copper and maroon), ‘Goldilocks’ (double amber), and ‘Sahara’ (a mix of dusky peach and caramel shades), all of which grow to around 60 centimetres. Another annual form to try is the clasping coneflower (R. amplexicaulis), which is useful for filling gaps at the front or in the middle of the border late in the season: it has bold-yellow flowers with tall brown hearts that resemble Mexican hats.
Where is the best place to plant rudbeckias?
Coneflowers bloom best in full sun, but will tolerate semi-shade. Ensure the soil is moderately fertile, retentive and well-drained by adding organic matter (such as peat-free compost).
Can you grow rudbeckias from seed?
Yes. Rudbeckias being grown from seed as annuals can be sown indoors (in a warm greenhouse or on a sunny windowsill) between February and April – sow thinly and shallowly (or don’t cover at all). Pot up seedlings once they are large enough to handle; alternatively, sow direct in April or May. Some perennial rudbeckias are also relatively easy to grow from seed, including R. maxima and R. triloba. The latter will often sow itself around the garden.
How to grow rudbeckias
Coneflowers dislike drought. In regions that experience hot, dry summers, mulch annually in spring (for instance, with organic peat-free compost) to ensure the plants can retain as much moisture as possible, and water daily during heatwaves.
Planting in full sun, with shelter from strong winds, will lure lots of butterflies. Leave the attractive seedheads on the plants for winter interest and to provide a habitat for insects.
Coneflowers can be lifted and divided every 4-5 years in spring to maintain flower power or to make new plants. The more rampant forms (especially R. laciniata) are best grown in larger gardens; otherwise, they need dividing regularly.
Can you grow rudbeckias in pots?
Yes, shorter forms are ideal for containers. Varieties of Rudbeckia hirta, such as copper-coloured ‘Cherokee Sunset’ and yellow ‘Prairie Sun’, reach 60 centimetres. Classified as H3 for hardiness, they are more tender than other rudbeckias. Sown early, they can be cultivated as annuals; otherwise, treat them as biennials or – in mild regions – as short-lived perennials.
What are the disadvantages of rudbeckias?
In wet years, slugs can strip young coneflower plants, leaving you with nothing but slime-coated stalks. Prevent such horror by using Nemaslug or crushed shells. In dry years, the plants can be plagued by powdery mildew if they’re not planted in a site that has good air flow or in soil that isn’t moisture retentive.
Five other essential yellow flowers for an early autumn blaze
Brighten the garden when the seasons change by growing these candescent yellow blooms:
Golden clematis (Clematis tangutica ‘Bill Mackenzie’) - This fabulous climber produces lantern flowers that look like they’ve been carved out of lemon peel, followed by silky seedheads that catch the light. Capable of 4 metres in well-drained soil, in sun or semi-shade.
Sneezeweed (Helenium ‘Riverton Beauty’) - Yellow heleniums are easy to grow perennials and produce a 1-metre tall crowd of shuttlecock daisies that feed pollinators in well-drained soil in full sun. Cut back in May or stake to prevent drunken stems.
Red-hot poker (Kniphofia ‘Bees’ Lemon’) - A wonderful plant that sends up 90-centimetre torches of clear yellow from green buds, luring bees and butterflies, and adding architectural impact to the border. Easy to grow in well-drained soil in full sun.
Perennial sunflower (Helianthus ‘Lemon Queen’) - Reliable for a substantial cloud of soft yellow at the back of the border, often flowering for months in warm weather and popular with butterflies and bees. Can reach 2 metres in humus-rich, well-drained soil in full sun.
Montbretia (Crocosmia ‘Paul’s Best Yellow’) - A doddle to grow for a source of warm colour in late summer and early autumn, this montbretia sends up sprays of amber gold amongst sword leaves that glow green in sunlight. Can reach over a metre in well-drained soil in sheltered sun.
