Rudbeckias with their daisy-like flowers and long blooming time are real work horses in the mid-summer to mid-fall gardens. They are all native to North America, easy to grow and relatively disease and pest free. There are 25 species in all with many varieties and cultivars offering a range of colours from bright yellow, through to orange, even red, burgundy and bi-coloured. Height can range from 30cm (12″) all the way up to 300cm (almost 10′). The three most common species home gardeners will find available in commerce are: Rudbeckia fulgida, Rudbeckia hirta, Rudbeckia triloba. I will mainly focus on these 3, but also touch on a few other species that may be of interest to the home gardener.

Rudbeckia fulgida

Commonly known as orange coneflower or black-eyed Susan. These long-lasting perennials bloom their hearts out from about mid-summer until mid-fall. Flowers are daisy like ray flowers that are golden-yellow with dark centers. They grow to about 60 to 100 cm (24-39″) in height, forming large clumps that spread via rhizomes and by self-seeding. They are generally easy to grow and fairly pest and disease free. Septoria leaf spot and angular leaf spot disease can sometimes be a problem. This species is very popular, and many varieties and cultivars can be found in local garden nurseries such as: Rudbeckia fulgida var sullivantii ‘Goldsturm’, Rudbeckia fulgida var fulgida, Rudbeckia fulgida var. sullivantii ‘Little Goldstar‘, Rudbeckia fulgida ‘Viette’s Little Suzie’, Rudbeckia fulgida var. deamii, Rudbeckia fulgida ‘American Gold Rush’, Rudbeckia fulgida var. speciosa.

Rudbeckia hirta

Commonly called black-eyed Susans, but are also referred to as gloriosa daisies, brown Betty or hairy coneflower. Unlike the fulgida species, hirta species are short lived perennials, biennials or annuals, but they self-seed freely and may maintain their presence in the garden that way. They also tend to be busier than fulgida, with larger flowers and more rays (petals) that tend to have a more rounded edge. Hirta in Latin means hairy, and the species was named for its hairy stems and leaves. Plants height ranges from 30 to 100cm (1-3ft.), according to variety and cultivar; with the same colour range as fulgida. There is a large selection of varieties and cultivars available such as: Rudbeckia hirta ‘Autumn Forest’, Rudbeckia hirta ‘Autumn Colors’, Rudbeckia hirta  ‘Sunbeckia ® Ophelia’, Rudbeckia hirta ‘Toto® Gold’, Rudbeckia hirta ‘Indian Summer’, Rudbeckia hirta ‘Prairie Sun’, Rudbeckia hirta ‘Moreno’, Rudbeckia hirta ‘Cherokee Sunset’, Rudbeckia hirta ‘Cherry Brandy’.

Rudbeckia triloba

Commonly known as brown-eyed susans. This species grows as a biennial or short-lived perennial. It is known for its densely branched habit, smaller flowers (but more of them) and fewer rays to each flower. Individual flowers measure about 4cm (1 1/2 in.) across. They also tend to bloom a bit later. The plants typically grow to about 60-90cm (2-3 ft.), but some cultivars can reach 150cm (5 ft.). The basal leaves are often trifoliate (three leaflets), and some have 3 lobes, for which the species is name after. Leaves are thinner than other species with a rough texture on both sides. This species is easy to grow from seed and can get a bit weedy in the garden. A couple of cultivars are Rudbeckia triloba ‘Blackjack Gold’ and Rudbeckia triloba ‘Prairie Glow’

Rudbeckia laciniata

Commonly known as Cutleaf Coneflower or Green-Head Coneflower. This perennial species is known for its deeply cut to pinnate leaves. Plants can reach heights up to 300cm (10′), but most varieties and cultivars are shorter. They can get a bit floppy and weedy. Flowers are often fully double and golden yellow, measuring 5-10cm (2-4″) across. They flower from August to September. A few varieties and cultivars include Rudbeckia laciniata ‘Golden Ball’, Rudbeckia laciniata ‘Hortensia’, Rudbeckia laciniata ‘Goldquelle’​, Rudbeckia laciniata ‘Juligold’.

Rudbeckia maxima 

Commonly known as giant or large coneflower. This species can grow up to 200-300 cm (7-10′) in height. Flowers are bright yellow measuring about 7cm (3″) with yellow-green cone centers rise to about 5-15 cm (2-6″) in height and mature to brown. Leaves are large measuring 60Hx25W cm (24″H x10” W). They prefer to grow near water and are less draught tolerant than most Rudbeckias. Bloom time is August and September.

Rudbeckia subtomentosa

Commonly known as sweet coneflowers due to their faint anise smell. These perennials measure about 100-150 cm (3-5′) tall. Flowers are bright yellow with tubular rays (petals) with broad tips. They commonly grow on the prairies, especially in moist areas. Blooms from July to September. Popular varieties include ‘Henry Eilers’ and ‘Little Henry’.

Rudbeckia occidentalis

Commonly known as western coneflowers. These perennials grow to about 60-180cm (2-6′) in height. Flowers are unique in that they have no rays (petals) just the center cone of the flower with a ring of green sepals around it. Foliage is silver-green in colour. Bloom time is July to October. ‘Green Wizard’ is a popular variety.

Photo credits: all photos taken by the author.

References:

Ballyrobert Gardens, (n.d.). Rudbeckia laciniata ‘Goldquelle’. https://www.ballyrobertgardens.com/products/rudbeckia-laciniata-goldquelle

Clemson University, (2017). RUDBECKIA. Home and Garden Information Center. https://hgic.clemson.edu/factsheet/rudbeckia/

Gardenia.net., (n.d). Rudbeckia fulgida var. deamii (Black-Eyed Susan). https://www.gardenia.net/plant/rudbeckia-fulgida-var-deamii

Gardenia.net, (n.d.). Rudbeckia hirta ‘Prairie Sun’ (Black Eyed Susan). https://www.gardenia.net/plant/rudbeckia-hirta-prairie-sun

Gardenia.net., (n.d). Rudbeckia hirta ‘Toto’ (Black Eyed Susan). https://www.gardenia.net/plant/rudbeckia-hirta-toto

Gardenia.net, (n.d.). Rudbeckia triloba ‘Blackjack Gold’ (Brown-Eyed Susan). https://www.gardenia.net/plant/rudbeckia-triloba-blackjack-gold

Gardenia.net, (n.d.). Rudbeckia laciniata ‘Hortensia’ (Cutleaf Coneflower). https://www.gardenia.net/plant/rudbeckia-laciniata-hortensia

Gardenia.net, (n.d.). Rudbeckia occidentalis (Western Coneflower). https://www.gardenia.net/plant/rudbeckia-occidentalis

Jeffers A. D., (2017). Rudbeckia. https://hgic.clemson.edu/factsheet/rudbeckia/

Missouri Botanical Garden, (n.d.) Rudbeckia fulgida var. sullivantii ‘Goldsturm’. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=i780

Missouri Botanical Garden, (n.d.). Rudbeckia hirta. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=277225

Missouri Botanical Garden, (n.d.). Rudbeckia hirta ‘Autumn Colors’. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=259575

Missouri Botanical Garden, (n.d.). Rudbeckia triloba. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b937

Missouri Botanical Garden, (n.d.). Rudbeckia maxima. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c864

Native Plant Trust, Go Botony, (n.d.). Rudbeckia fulgida — showy coneflower. https://gobotany.nativeplanttrust.org/species/rudbeckia/fulgida/

North Carolina Extension, (n.d.). Rudbeckia fulgida. https://plants.ces.ncsu.edu/plants/rudbeckia-fulgida/

North Carolina Extension, (n.d.). Rudbeckia hirta. https://plants.ces.ncsu.edu/plants/rudbeckia-hirta/

North Carolina Extension, (n.d.). Rudbeckia Hirta ‘Autumn Colors’. https://cutflowers.ces.ncsu.edu/rudbeckia-hirta-autumn-colors/

North Carolina Extension, (n.d.). Rudbeckia triloba. https://plants.ces.ncsu.edu/plants/rudbeckia-triloba/

North Carolina Extension, (n.d.). Rudbeckia laciniata. https://plants.ces.ncsu.edu/plants/rudbeckia-laciniata/

North Carolina Extension, (n.d.). Rudbeckia maxima. https://plants.ces.ncsu.edu/plants/rudbeckia-maxima/

North Carolina Extension, (n.d.). Rudbeckia subtomentosa. https://plants.ces.ncsu.edu/plants/rudbeckia-subtomentosa/

North Creek Nurseries, (n.d.). Rudbeckia triloba ‘Prairie Glow’. https://www.northcreeknurseries.com/plantName/Rudbeckia-triloba-Prairie-Glow

Perennials.com, (n.d.). Rudbeckia fulgida ‘Goldsturm’. https://www.perennials.com/plants/rudbeckia-fulgida-goldsturm.html

Perennials.com, (n.d.). Rudbeckia hirta ‘Prairie Sun’. https://www.perennials.com/plants/rudbeckia-hirta-prairie-sun.html

Perennials.com, (n.d.). Rudbeckia hirta ‘Toto Gold’. https://www.perennials.com/plants/rudbeckia-hirta-toto-gold.html

Royal Horticultural Center, (n.d.). Rudbeckia triloba ‘Blackjack Gold’. https://www.rhs.org.uk/plants/376020/rudbeckia-triloba-blackjack-gold/details

Royal Horticultural Center, (n.d.). Rudbeckia laciniata ‘Juligold’. https://www.rhs.org.uk/plants/203940/rudbeckia-laciniata-juligold/details

University of Wisconsin-Madison Extension, (n.d). Brown-eyed Susan, Rudbeckia triloba. https://hort.extension.wisc.edu/articles/brown-eyed-susan-rudbeckia-triloba/

Wikipedia, (rev. 21 August 2022). Rudbeckia. https://en.wikipedia.org/wiki/Rudbeckia

Xera Plants, (n.d.). Rudbeckia hirta ‘Autumn Colors’. https://xeraplants.com/plants/rudbeckia-hirta-autumn-colors/

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