Rudbeckia fulgida var. fulgida (black-eyed Susan)
The Rudbeckia genus features recognizable native wildflowers in the Asteraceae family that were historically used as medicinal herbs by Native Americans and have been cultivated and utilized in gardens and landscapes since the 19th century. The plants in this genus are usually hardy in USDA zones 3–9 and are most commonly known as black-eyed Susan or brown-eyed Susan. Sometimes, these two species are confused with one another and names are often used interchangeably. However, if you look more closely you will notice that black-eyed Susans are overall larger in size with more petals and larger leaves than brown-eyed Susans, although certain cultivars are the exception to this. Additionally, brown-eyed Susans tend to have longer bloom periods than most black-eyed Susans. A few Rudbeckia species are also sometimes referred to as gloriosa daisies or coneflowers even though coneflower is traditionally a common name for the distinct genus, Echinacea. Black-eyed Susans are notable for being more daisy-like in appearance than other coneflowers.
Rudbeckias are mainly short-lived perennials while some are considered annuals or biennials. These perennials tend to die out after a couple of seasons but the plants do self-seed very easily given the right conditions, so they can manifest in a sustainable population for future generations to come. The group is generally a hardy, low-maintenance plant, which grows across North America and is especially common in the eastern United States. It grows relatively well in both damp and drier soil conditions but prefers consistent and moderate moisture as well as full sun conditions as much as possible.
Rudbeckia fulgida var. fulgida is commonly known as Black-eyed Susan or orange coneflower. It is found both in gardens and in prairies across the continent. It has a smaller central floret, that is a unique brownish purple, and iconic bright yellow petals. These black-eyed Susans grow rather quickly to around 2–3 feet and flower soon after. Similar to prairie coneflower, these plants tolerate harsher sun and can grow in dry soils.
Rudbeckia subtomentosa ‘Henry Eilers’ (sweet coneflower)
Rudbeckia subtomentosa ‘Henry Eilers’ is a variety of Rudbeckia with unique stand-out petals. This is one of the nine different types of Rudbeckia found at the Arboretum that includes five unique species. It is commonly known as sweet coneflower and is noteworthy for its thin petals. Like other Rudbeckias, this flower can be found in the Pollinator and Bird Garden and in the Childhood’s Gate Children’s Garden (look just across from the quaking aspens)! R. subtomentosa translates to ‘hair like,’ with petals that appear long and skinny (especially pronounced in ‘Henry Eilers’) compared to other coneflowers. These flowers are often chosen by gardeners for both their distinctive look and their pleasant aroma.
Rudbeckia triloba (brown-eyed Susan)
Rubeckia triloba (pictured above) is commonly known as brown-eyed Susan and has specific qualities that set it apart from others in its genus. These are not limited to just its appearance however, with brown-eyed Susans being classified as shorter-lived perennials or as annuals. This plant’s leaves stand out, being a darker shade of green, while the plant is also taller than most black-eyed Susans. The flowers themselves are similar to other Rudbeckias, but they are noticeably smaller and more clustered.
Rudbeckia laciniata ‘Herbstsonne’ (cutleaf coneflower)
Another unique species is Rudbeckia laciniata, known as cutleaf coneflower. Another common name is green-headed coneflower, which describe the flower’s green floret that helps differentiate it from others. Cutleaf coneflowers can grow much taller, usually between three and ten feet off the ground. Additionally, these flowers bloom beginning in June and last until November, which makes it a great pick if you’re looking to extend the color in your garden into autumn.
Rudbeckia hirta ‘Autumn Colors’ (black-eyed Susan)
Like Rudbeckia triloba, Rudbeckia hirta is also a short-lived perennial plant. This flower is commonly referred to as just black-eyed Susan, and most varieties of the species look like variations of the typical flower. R. hirta has relatively shorter, rounded flowers. While flowers are usually shades of yellow, the variety R. hirta ‘Autumn Colors’ (pictured above) has shades of yellow, orange, and red across their leaves. Keep an eye out for other colorful cultivars, such as Rudbeckia hirta ‘Cherokee Sunset,’ in our upcoming seasonal fall displays in the gardens — these are great picks for harvest season containers or bouquets!
Regardless of the species chosen, there are several benefits to all Rudbeckia. If you’re looking for a durable and self-sowing plant that can tolerate hotter temperatures and sunlight while blooming all summer long and even into fall, then you might want to consider this plant for your next garden addition. As an added bonus, like many other plants in the Asteraceae family, they also attract many pollinators with their pollen and nectar offerings, including bees, butterflies, and birds. Keep an eye out for these blooms during your late summer/early autumn stroll and don’t forget to access the Arboretum Explorer Tool on your mobile device to find the locations and more information on these plants in the gardens!
Rudbeckia fulgida var. fulgida (black-eyed Susan)