Ontario Weeds: Black eyed
susan
Table of Contents
- Name
- Other Names
- Family
- General Description
- Stems and Leaves
- Flowers and Fruit
- Habitat
- Similar Species
- 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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