Discover rudbeckia

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This article was published 24/06/2023 (1184 days ago), so information in it may no longer be current.

Rudbeckia Black-Eyed Susan did not have a place on my top 10 list of great garden plants until about five years ago. For one thing, I’ve never wanted too much yellow in my garden, but I also mistakenly pigeonholed rudbeckia as a mid-summer to fall flower. Two rudbeckias changed my perspective almost simultaneously and opened the door to exploring a host of varieties including some without a trace of yellow or golden colour in their decidedly daisy-like flowers.

Rudbeckia, pronounced rood-BEK-e-a, is named after Swedish botanist Olof Rudbeck (1630-1702). A member of the sunflower family (Asteraceae), rudbeckia has daisy-like flowers with ray-like petals around a prominent central cone. Native to North America, rudbeckia had several medicinal uses at one time. Root extracts were used for making tea as well as for treating saddle sores on horses.

Some rudbeckias are long-lived perennials, but others are biennials or annuals. Rudbeckia laciniata, for example, is commonly known as cutleaf coneflower and is said to have a lifespan of 25 years. Hardy to Zone 2, Rudbeckia laciniata proved to be a game-changer for me in the sense that it introduced masses of yellow flowers to my garden. It was recommended to me by Andrew Fehr, perennials specialist at Sunshine Greenhouse in Steinbach. Since I was writing a piece about perennial giants at the time, I decided to try it in my garden. Rudbeckia laciniata makes a considerable impact at the back of the border. Native to North America, the bright green leaves are huge and deeply cut. It grows to a height of 2 to 2.5 metres and produces single lemon-yellow flowers with showy green central cones on sturdy stems from mid-summer to September. Rudbeckia laciniata does not have any pest or disease problems. I have read that it is very drought tolerant but, in my garden, it prefers even moisture. Rudbeckia laciniata Goldquelle is a more compact (3 ft or 90 cm) version with double lemon-yellow flowers which I would also like to try.

Rudbeckia Goldsturm is widely touted as one of the best Black-Eyed Susan perennials for northern gardens. With a compact (24 inches or 60 cm) size, Goldsturm has yellow-orange daisy-like flowers with a prominent black centre cone and dark green foliage. Goldsturm is an ideal choice for hot, sunny locations and is extremely drought tolerant once established. It also offers reliable hardiness and comes back year after year.

American Gold Rush is the 2023 Perennial Plant of the Year. It has notably thinner, hairier leaves and several attributes — disease resistance, tolerance of drought and high humidity, an abundance of 7 cm golden yellow flowers with arching rays and a reddish halo surrounding a deep chocolate cone. American Gold Rush has golden-yellow recurved flowers with black centres. It has been bred for its resistance to Septoria leaf spot, a fungal disease that appears as small, dark brown spots on leaves (starting at the bottom of the plant) during cool, wet periods. However, when American Gold Rush was trialed over a three-year period in the All-America Selection plant trial at Vanstone Nurseries in Portage la Prairie, it did not demonstrate the same winter hardiness or longevity as Goldsturm which is hardy to Zone 3a.

New for 2023, Rudbeckia GoldBlitz from PanAmerican Seed is one that has intrigued me. When I grew it in my garden last year, I was surprised by its rapid growth and first-year flowering. To say that it overwintered well in my garden would be an understatement.

Hardy to Zone 3a, GoldBlitz made an early appearance in spring and has already reached its mature size (24 inches or 61 cm tall and wide). Flower buds have started forming. GoldBlitz has a slightly smaller leaf and flower size than Goldsturm and is said to bloom two to three weeks earlier.

Rudbeckia fulgida Viette’s Little Suzy is a petite Black-Eyed Susan that is perfect for the front of the border or in containers. Hardy to Zone 3, this variety grows only 12 to 18 inches tall (30-45 cm) but the yellow flowers are also small as well. It has its place in the garden to be sure and I picked up another one this spring, but richly coloured, large-flowered rudbeckias are becoming more and more tempting.

Prior to the introduction of Rising Sun Chestnut Gold in 2018, I paid scant attention to annual varieties of rudbeckia. But I couldn’t resist Rising Sun Chestnut Gold. It is hardy to Zone 7 and features bicolour flowers that are 12 to 15 cm across in shades of yellow, orange and red. It took a decade of research, development and testing by Green Fuse Botanicals to develop this daylength-neutral rudbeckia. Why is this a game changer? Rudbeckia is an obligate long-day plant which means that it does not initiate flowering until the days are at their longest. Typically, rudbeckia needs about 14 hours of daylight before it starts to flower. Rising Sun Chestnut Gold, however, blooms continuously from spring until fall.

Now Green Fuse Botanicals has introduced a new daylength-neutral rudbeckia series called Dakota. “Rudbeckia is one of the largest breeding projects for Green Fuse Botanicals,” said Jim Devereux, CEO, in a recent email reply. “Because we have achieved this key attribute of daylength neutrality in both the Rising Sun Chestnut Gold (Zone 7) and the Dakota series (Zone 5), we are able to move forward with other selection criteria such as habit and hardiness. We will be able to achieve Zone 4 (hardiness) I believe, if we have not already.”

Dakota Gold is the first large-flowered Rudbeckia hirta type that is truly hardy to Zone 5. The massive, daylength-neutral flowers are 7 inches (17.78) cm across. I’m more than willing to grow Dakota Gold as an annual in my garden but just imagine if Green Fuse Botanicals succeeds in achieving Zone 4 hardiness in daylength-neutral rudbeckia. You and I could be growing large-flowered rudbeckia that blooms from spring to fall in our gardens and overwinters.

We’ll have to be patient but, in the meantime, there is an extraordinary number of richly coloured Black-Eyed Susan cultivars that have riveting flowers. Denver Daisy Black-Eyed Susan, for example, features masses of single, golden daisies with mahogany-red centres and deep chocolate brown cones. I planted Denver Daisy for the first time this spring and the first flower stopped me in my tracks. Gorgeous mahogany colour forms a wide ring around the centre cone and contrasts beautifully with the golden yellow of the 7-10 cm wide flowers. The plant tag that came with Denver Daisy says that it is a Zone 3 plant however that is not accurate. It is closer to Zone 5 hardiness. I also planted Rudbeckia Cherry Brandy Gloriosa Daisy which has cherry-red flowers with black centres. The tag says Zone 4 but most sources rate it as Zone 5. It remains to be seen if Cherry Brandy will be an annual, biennial, or perennial. Both Denver Daisy and Cherry Brandy will be beautiful as cut flowers.

The National Garden Bureau has named 2023 as the Year of the Rudbeckia.

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