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.
Photos:
Leaves: "Rudbeckia hirta (4991891142)" by Matt Lavin is licensed under flickr.
Spent bloom detail: "Withered Rudbeckia - Rudbeckia flétrie" by Monteregina (Nicole) is licensed under flickr.
All other photos by TELCS.
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