poke milkweed (Asclepias exaltata)
Asclepias bicknellii Vail
Asclepias phytolaccoides Pursh
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name of poke milkweed
is Asclepias exaltata L.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL DESCRIPTION:
Habit: Poke milkweed is a tall, erect, native perennial that reaches a height
of 4 to 6 feet with a 1 to 2 feet spread and has a single primary stem con-
taining a white juice.
Leaves: Leaf arrangement is opposite with large, thin, tapering lanceolate
ovate to oblong shaped stalked leaves. Leafs are dark green, simple with
entire margins and pinnate venation and have pointed tips and bases.
Flowers: Loose, spreading few-flowered umbels have clusters of white-
pinkish to almost purplish flowers drooping elegantly on slender stalks.
Flowers complete, regular, 5 part, with stamens, petals and sepals attached
below the ovary. It has awl-shaped horns coming out of and attached well
below the hoods. Flower heads are reminiscent in form of exploding fire-
Fruit/Seeds: Flowers give way to elongated, from 6" to 10" long, erect
seed pods with silky hairs that persist all summer and well into autumn.
A dry, many-seeded fruit is composed of a single carpell and opening
along one side. Seeds are dispersed by white, parachute like hairs.
Roots: Poke milkweed has one primary root.
REGENERATION PROCESS: Poke milkweed propagates itself by re-
HABITAT TYPES: Often found in moist upland woods and openings,
particularly where there is sufficient moisture.
SITE CHARACTERISTICS: The poke milkweed is a woodland native
and easily grown in any moist (but not wet), average to rich, neutral to
slightly acidic soil in part shade, filtered light, or open bright shade.
SEASONAL DEVELOPMENT: Poke milkweed blooms in early to
mid-summer (June and July).
GENERAL DISTRIBUTION: Poke milkweed is primarly distributed
east of the Mississippi/Missouri Rivers, only occassionally extending
rather west (Minnesota and Iowa). It has not been recorded in Florida of
the maritime provinces of Canada; it has been recorded in Quebec and
Ontario. It does not naturally occur in most of the Great Plains states or
provinces, the southwest, Rocky Mountain states of provinces, or the far
western or northwestern states or provinces.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: All Genus Asclepias "milkweeds" are very
popular butterfly attractors. Poke milkweed attracts silver-spotted
skippers, pearl crescents, cloudywings, great spangled fritillaries and
tiger swallowtails to name a few. It is a larval food source for the monarch
butterfly. Milkweed contains cardenolides (cardiac-active steroids) which
are consumed by monarch caterpillars during feeding and then sequestered
in their bodies even after the adult monarchs emerge from their pupae.
These cardenolides make monarchs toxic and bitter-tasting to birds and
other vertebrate predators (see following entry for swamp milkweed for a
more comprehensive discussion of importance and uses).
Ohama Indians used to eat the root raw to stomach problems.
Poke milkweed has been used as an ornamental in woodland gardens and
shade gardens. All parts of the plant are considered poisonous in large
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