Rudbeckias (Rudbeckia spp.), also commonly called black-eyed Susan or coneflower, among other names, are American natives beloved for their cheerful yellow and orange daisy-like flowers. The rudbeckia family includes perennials, biennials and annuals, all easy to grow in full sun and tolerant of a wide range of soil conditions. Rudbeckias attract butterflies to the garden, and make good cut flower subjects.
Most often called the black-eyed Susan or orange coneflower, plants of Rudbeckia fulgida feature 2-inch-wide yellow flowers with either brown or black centers, and deep green, lance-shaped leaves covered with fine hairs. This perennial is reliably hardy in zones 3 through 9. The species form of Rudbeckia fulgida grows up to 3 feet by 3 feet, although cultivars are slightly smaller. Popular choices include “Goldsturm," with bright orange-yellow blooms produced for 7 to 8 weeks beginning in mid-summer, and “Viette’s Little Suzy,” with petite yellow flowers on a plant only 10 to 14 inches high.
Plants of Rudbeckia laciniata, or cut-leaf coneflower, are descended from American wildflowers of the eastern U.S. and hardy in zones 3 through 9. These rudbeckias take their name from their deeply-lobed leaves. The species plant can reach large proportions, as high as 10 feet and 4 feet around, and is better planted in a meadow than a garden border. A more refined cultivar is the 7-foot-high “Herbstonne,” which sends up long flower stalks in late summer to early autumn. Each flower's lemon-yellow rays droop downward while the central green cone rises prominently above. “Goldquelle,” only 3 feet high and 1 1/2 feet wide, has double blooms of lemon-yellow.
Rudbeckia hirta, also called the gloriosa daisy or black-eyed Susan, is a biennial or a short-lived perennial hardy in zones 3 through 7, but it’s often treated as an annual throughout the U.S. because it will bloom in its first season. This rudbeckia has an upright habit, reaching from 3 to 4 feet tall and 1 1/2 feet wide. Cultivars include “Irish Eyes,” featuring golden flowers with a light green cone; “Cherokee Sunset,” with semi-double flowers in rich autumn shades of yellow, orange, bronze and brown; and “Cherry Brandy,” with unusual blooms of bright cherry red that deepens to maroon toward the flower’s black-coned center.
Other rudbeckia species include Rudbeckia maxima, also called giant coneflower or black-eyed Susan, which grows from 3 to 6 feet high and is hardy in zones 4 through 8. Rudbeckia triloba, or brown-eyed Susan, is hardy in zones 4 through 7, and produces delicate sprays of yellow flowers with purple-black centers. This biennial self-sows in the garden. Rudbeckia subtomentosa, or sweet coneflower, is hardy in zones 4 through 8, and takes its common name from the vanilla-anise scent of its downy leaves. Its flowers are golden yellow with a brownish-purple cone.
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