Rudbeckia hirta


Cottage gardens and perennial borders cannot exist without Rudbeckia hirta. Okay, that is an overstatement, but their daisy-like flowers are hard to resist, right up there with Echinacea and Helianthus, among others. Native to the Midwest, their informality lends themselves to another design aesthetic, the prairie garden.


The University of Minnesota Extension defines prairies as "ecosystems that grow where the climate dictates limited rainfall, hot summers and cold winters. Plants growing in prairies are typically non-woody, or herbaceous plants. Trees are rare in a prairie and are confined to wet areas or along rivers or streams." California has similar ecosystems, albeit not as cold and wet as Minnesota. For ornamental landscapes, however, we can mimic the necessary conditions while adapting the plant palette to local needs. For example, California has its own native black-eyed Susan, known as Rudbeckia californica. I have grown it quite successfully, except now the wild rabbits keep eating it. In a small way, this illustrates both the purpose of a prairie and an apparent need by local wildlife.


If I were to design in the prairie style, I would consider the use of other forbs, which like Rudbeckias are herbaceous perennials that are not grasses. Grasses, known as graminoids, would be included, too, and I would limit the amount of trees if I wanted to be literal to the form. Prairies typically have few if any trees with a focus on grasses and wildflowers. This is separate from a meadow, having very low growing and spreading species.


In my imagination, I see replacing useless lawns (keeping useful lawns) with meadows, and add prairie plants in masses as a transitional zone to woodland or forest, depending upon the scale of the project of course. Forbs and graminoids are also popular for designing into rain gardens, a type of green stormwater infrastructure (GSI). Depending upon the species, their roots can absorb pollutants found in the stormwater, complimenting the designs that clean the water before entering a local waterway.


As with many herbaceous perennials, R. hirta and its kind are winter dormant. At first frost, the foliage will wither, although flower stalks might linger. This is the time to prune back to the ground and expect them to regrow next spring. While winter landscapes may look barren (Minnesota should be covered in snow), their worth the wait for all the prolific blooms next year.


facts

Botanical Name: Rudbeckia hirta

Rudbeckia: Honorees, father/son scientists Olaus Johannes Rudbeck and Olaus Olai Rudbeck.

Hirta: Hairy

Common Name: Black-eyed Susan

Family Name: Asteraceae


Origin: Central United States


design considerations


Positioning: Foreground, slope

Garden Themes: Prairie, cottage, cutting, perennial, pollinator

Uses: Cut flowers, border, foundation, mass


identifying characteristics


Type: Herbaceous perennial

Form: Clump, erect, may be open

Texture: Medium

Size: 4' with blooms (often smaller) by 2' wide


Outstanding Feature(s): Flower


Stem: Green, pubescent

Leaf:

  • Type: Simple

  • Arrangement: Alternate

  • Shape: Spatulate, lanceolate, or ovate

  • Margin: Serrate to entire

  • Color: Dark green to medium green

  • Surface: Pubescent

Flower: Sprint to summer. Composite, radial, showy, gold, yellow, orange, red, burgundy, two-tone, per cultivar.

Fruit: Summer to fall. Brown capsule.


cultural requirements, tolerances & problems


Sunset Zones: 1-24 (winter annual in zones 12 & 13)

USDA Zones: 3-8


Light: Sun

WUCOLS SF Bay Area Hydro Zone: Moderate

Soil:

  • Texture: Sand, loam, clay

  • Moisture Retention: Well-drained with brief periods of dryness

  • pH: Highly acidic to highly alkaline

Tolerances: Deer, drought, salt

Problems: Slugs, snails (on young leaves), may reseed in favorable conditions

  • Branch Strength: N/A

  • Insects: Tent caterpillars

  • Disease: Powdery mildew


citations & attributions


Bayton, R. (2019). The Royal Horticultural Society's the Gardener's Botanical: An Encyclopedia of Latin Plant Names. London: Mitchell Beazley.


Extension Gardener. "Rudbeckia hirta." North Carolina State University, Raleigh. Accessed on August 25, 2021, from https://plants.ces.ncsu.edu/plants/rudbeckia-hirta/.


Norris Brenzel, K. (Ed.). (2012). The New Sunset Western Garden Book. New York: Time Home Entertainment, Inc.


Plant Finder. "Rudbeckia hirta." Missouri Botanical Garden, St. Louis. Accessed on August 25, 2021, from "https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=277225.


Planting and Growing Guides. "Planting and maintaining a prairie garden." University of Minnesota Extension, Minneapolis. Accessed on August 25, 2021, from https://extension.umn.edu/planting-and-growing-guides/planting-and-maintaining-prairie-garden.


Water Use Classification of Landscape Species. "WUCOLS IV Plant List." University of California, Division of Agriculture and Natural Resources, Davis. Accessed on July 27, 2021.

https://ucanr.edu/sites/WUCOLS/Download_WUCOLS_IV_List/.


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