garden cornflower
Family
AsteraceaeScientific Name
Centaurea cyanusOther Common Names:
garden cornflower
Synonyms (former Scientific Names):
Leucacantha cyanus
Habit
Erect winter annual that grows to 1.2 m tall with a taproot and often a weed in small grains.
Leaves
Leaves are alternate approximately 5 to 15 cm long and 1 cm wide, lance shaped to linear, hairy, and has entire or slightly toothed margins. Due to the leaf appearance, these plants are often confused for a grass.
Identifying Characteristics
An erect winter annual with long white hairs and blue, white, or pink flowers. Plants may reach 3.5 feet in height.This weed is sometimes confused with both Spotted Knapweed (Centaurea maculosa) and corn cockle (Agrostemma githago). However, spotted knapweed forms a basal rosette of leaves during the first year of growth and its leaves are much more deeply lobed than those of cornflower. Additionally, the leaves of corn cockle are joined across the stem and the stems of this plant are swollen at the nodes whereas neither of these characteristics occurs with spotted knapweed or cornflower.
Flower Seed Head
Many solitary heads are produced on long flower stalks (peduncles). Flowers are 2.5 to 5 cm wide and 1.5 to 3 cm long.They are pink, purple, white, and sometimes blue in color.
Seed Fruit
The seed is an achene that is about 4 mm long and 2 mm wide, and is gray in the middle and yellow brown on the ends with pubescense on one end.
Where Found
Found throughout the eastern half of the United States and also in the western states from California to Washington.
Growth Habit
upright and nonwoody
Thorns or Spines
not present
Approximate Flower Diameter
Varies:
quarter,
half dollar,
larger
Dominant Flower Color
Varies:
white,
blue,
purple,
pink
Flower Symmetry
radial symmetery
Leaf Hairs
has hairs
Leaf Shape
Varies:
needle,
lance
Leaf Arrangement
alternate
Leaf Margin
Varies:
entire,
serrated
Leaf Structure
simple
Leaf Stalk
none
Stem Hairs
has hairs
Stem Cross Section
round or oval
Milky Sap
not present
Root Structure
taproot
Life Cycle
winter annual
Ochrea
not present
Plant Type
Herb