Asclepias syriaca

Common milkweed flowering

Common milkweed flowering

This native perennial plant is 2-6′ tall and unbranched, except sometimes toward the apex, where the flowers occur. The central stem is relative stout, pale green, terete, and usually short-pubescent (less often glabrous). The opposite leaves are up to 8″ long and 3½” wide, broadly oblong in shape, and smooth along their margins. The upper leaf surface is pale-medium to dark green and hairless above, while the lower leaf surface is densely covered with woolly hairs that are very short. There is a prominent central vein along the length of each leaf, and finer side veins that radiate outward toward the smooth margins. When either the central stem or leaves are torn, a milky sap oozes out that has variable toxicity in the form of cardiac glycosides.

The flowers are very popular with many kinds of insects, especially long-tongued bees, wasps, flies, skippers, and butterflies, which seek nectar.

Phenophases

  1. First Flower: Date the first flowers are fully open. When open, you will see the stamens among the unfolded petals.
  2. Full Flower: Date when half or more of the flowers are completely open
  3. First Ripe Fruit: Date when you notice the first fruits becoming fully ripe or seeds dropping naturally from the plant. Ripening is indicated by the berries turning red, yellow, orange, or maroon.
  4. Full Fruiting: Date when half or more of the fruits are completely ripe or seeds are dropping naturally from the plant.
  5. All Leaves Withered: Date when most or all of the leaves that developed this season, have lost green color or are dried and dead.

Information from: www.wildflower.org and www.illinoiswildflowers.info

 

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