Meenal Harankhedkar, Director of Horticulture

Jul 31, 20202 min

Botanist's Lens: Black-Eyed Susan

A sunny aster of the prairies, open pastures and even eroded soils.

Mass planting of Black-eyed Susan in the ornamental gardens. This area is a perfect example of how Rudbeckia sps., a biennial, acts as a perennial when in the right habit. This mass border is less than three years old and was started with a handful of healthy Rudbeckias. Thanks to the Chaney Foundation and Unity Gardens for the start of a pollinator oasis.

Rudbeckia sps., Black-eyed Susan - the State flower of Maryland - is a rewarding robust perennial aster that every sunny garden should adorn. Each flower head has close to 500 small flowers and to numerous pollinators, this sunny aster is nectar heaven!

It belongs to the aster family, enjoys full sun, open areas and even disturbed soils. With tolerance to drought, disturbed soils, and the added benefit of self seeding, Rudbeckias make for an extremely rewarding plant. For a larger impact, plant them in mass borders, but they can also create good impact in a small sun pocket window.

Lemon Lime wonders in the woodland gardens sun pocket: Hakonechloa grass (lime green) with Black-eyed Susan flowers planted in a border.

Most of the Rudbeckias at London Town are in the driest, sunniest spot, but there are a few tucked into the woodland gardens, in small sun pockets. The color lasts for long, and it brightens up the woods. In the woodland gardens at London Town, one of the sun pockets has chartreuse green Hakonechola and Rudbeckias mixed in a border, it makes for a lemon lime color palette to enjoy throughout summer. Also with Tiger Lilies in the back drop, it is a pollinator oasis.

Skipper moth relishing the Black-eyed Susan nectar

"Most are considered perennial; however, there are some annual species, such as R. hirta. Species that are commonly available are R. hirta, R. fulgida, R. grandiflora, and R. triloba." https://hgic.clemson.edu/factsheet/rudbeckia/

"Black-Eyed Susan matures rapidly in average, well-drained soil in sun to partial shade. Because it blooms in the first year when planted from seed in early spring, it is seen as an annual. However, it freely self-seeds and usually remains in the garden." https://plants.ces.ncsu.edu/plants/rudbeckia-hirta/

Black-eyed Susan bud

Watch out though, all the qualities - including drought and disturbed soil tolerance, full sun and, ability to self seed very easily - make for a concoction of an invasive/aggressive habit. A plant that can survive and thrive in neglect is usually the one that could flourish and out compete the other needy plants. But when you have a sunny golden flower that helps local pollinators, adds ornamental value, and isn't leggy or unsightly, it can still pass with flying colors and make it to every garden, even while having an invasive tendency.

Rudbeckias enjoy open disturbed soils but will flourish when given the room to thrive. It is a biennial that can act as a perennial when in a happy spot. Having rhizomatous roots makes it difficult to remove, and its self seeding ability adds to yearly recurrence in the same spot or more. Now to me, that's a happy problem to have in case of Black-eyed Susan's, because who doesn't want a beautiful sunny golden daisy border that will also feed the local pollinators for many summers to come.

Rudbeckia maxima: http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c864

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