Ministry of Agriculture, Food and Rural Affairs

Ontario Weeds: Black eyed susan

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Stems and Leaves
6. Flowers and Fruit
7. Habitat
8. Similar Species
9. For more information...

Name: Black-eyed Susan, Rudbeckia serotina Nutt.,

Other Names: Coneflower, Yellow-daisy, rudbeckie herissée, marguerite jaune, marguerite orangée

Family: Composite or Aster Family (Compositae) 

General Description: Perennial or sometimes biennial, reproducing only by seed. Photos and Pictures

Black eyed susan.

Stems & Leaves: Stems are erect, 30 -100 cm (12 - 40 in.) high, single or with a few branches in the upper parts, more or less rough-hairy throughout. Leaves are alternate (1 per node); lower leaves long-elliptic, tapering to a long stalk (a); upper leaves (b) narrow, stalkless, smooth-margined or somewhat coarsely toothed; all leaves rough-hairy and usually dark green;

Flowers & Fruit: Flower heads large and showy at the ends of long, thin, erect branches, 2.5 -7.5 cm (1 -3 in.) in diameter with ray florets (c) orange to orange-yellow and spreading like spokes of a wheel; disk florets (d) dark purple or blackish, individually very small and tightly packed on a conic receptacle forming a prominent, hard, dark, raised centre in the head, like the hub of a wheel; seeds black, 4-angled with fine lengthwise lines. Flowers from mid-June to September.

Habitat: Black-eyed Susan is a native plant in the Great Plains but was introduced into Ontario and has spread aggressively throughout the province in meadows, pastures, edges of woods, river valleys, lakeshores and roadsides, usually in coarse-textured soils.

Similar Species: It is distinguished by its long-elliptic, rough-hairy leaves, and showy, long-stemmed flower heads with bright yellow ray florets and dark purplish to blackish disk florets.

Related Links

... on general Weed topics
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control

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