common milkweed
Family
AsclepiadaceaeScientific Name
Asclepias syriaca
Other Common Names:
silkweed
silky swallow-wort
Virginia silkweed
butterfly flower
Synonyms (former Scientific Names):
Asclepias kansana
Asclepias intermedia
Habit
The plant tends to bloom from around June to August but the seedlings do not flower until the second year.
Leaves
Leaves are oval shaped anywhere from 10-30 cm long and 5-11 cm wide. The lower surface of the leaves contain fine hairs while the upper portion is lacking hair structures.
Identifying Characteristics
Every part of the plant, mainly the stem, excretes a white/milky sap when broken in two. The stems are initially green but as they mature they form a red tint. The plant's root structure is a taproot with a deep rhizome.
Flower Seed Head
Flowers are in clusters of approximately 20-130, located at the end of a stem which is on a long, slender stalk. They are purple to white with a greenish look.
Seed Fruit
The fruit is hairy and teardrop-shaped, which are follicles. Each fruit contains numerous seeds of about 6-10 mm in length. The seeds are flat and brown and have some silky hairs.
Where Found
The common milkweed is found mainly in the northeastern US, Virginia to Georgia, and west to the Rocky Mountains as well. The plant has been found to grow in meadows, roadsides, reduced-tillage fields, and some other open habitats.
Growth Habit
upright and nonwoody
Thorns or Spines
not present
Approximate Flower Diameter
pencil
Dominant Flower Color
Varies:
white,
purple
Flower Symmetry
radial symmetery
Leaf Hairs
has hairs
Leaf Shape
lance
Leaf Arrangement
opposite
Leaf Margin
entire
Leaf Structure
simple
Leaf Stalk
Varies:
none,
shorter than leaf
Stem Hairs
Varies:
has hairs,
no hairs
Stem Cross Section
round or oval
Milky Sap
present
Root Structure
rhizomes present
Life Cycle
perennial
Ochrea
not present
Plant Type
Herb