22 July 2014

Milkweed in midsummer

The timing varies with latitude and microclimate, but in general, common milkweed reaches its floral maximum in midsummer.    It would be a bit of an exaggeration to call the plants "magnificent" or "stately," but they are certainly impressive, rising 4-5 feet high with a thick stem to help support a half-dozen blossoms as big as softballs.

Through the summer months those compound blossoms provide an abundance of nectar and pollen not just for the Monarchs, but for other butterflies and innumerable solitary bees and other insects. 

I posted earlier this summer about the complex morphology of the blossoms and how their strategy for pollination makes the blossom occasionally lethal to unwary small insects.  That is an uncommon occurrence, and for the most part when one wanders through a patch of mature milkweed, there is an abundance of small insects hovering nearby (and often a resident crab spider lurking in the flower). 

The fragrance is strong and reasonably pleasant, but not a prominent feature of the plant.  Midsummer will also find the plant hosting a variety of other insects - aphids tended by ants, milkweed beetles and milkweed bugs, lacewings and their eggs, and the milkweed tussock moth.  The ecology is complex and worthy of a separate post (next summer).

Next step:  the spectacle of seed production.


  1. ours has larger/fewer white flowers.

    draws hummingbird moths.

  2. I'm wanting to plant a milkweed patch, any suggestions on where to pick up some seeds?

  3. I remember as a child finding mature, dried milkweed pods and breaking them open to find the silky floss inside. It was so soft.

  4. We have no milkweed, but recently planted a Passiflora incarnata. A week or so ago, I noticed its leaves were being eaten, and further examination showed a large number of bristly orange caterpillars. I looked them up, and discovered that passion vines are toxic to most insects, producing a cyanic compound. but are fed on by the caterpillars of the Gulf Fritillary, which superficially resemble the Monarch.
    I thought.... I'll keep an eye on those and photograph them for Minnesotastan, but when about a week later, I went to show my wife.... No caterpillars! There must have been about fifty, now I could see none.
    I discover that the caterpillars, by virtue of their solely passiflora diet, are toxic to most predators, so where did they all go? I see no chrysalis nearby.
    A possible culprit might be the little geckos, abundant around here. I don't know.
    But we're aiming to plant more native wildflowers,especially milkweed, for next year.
    If I find them, I'll photograph and report.

  5. I believe I've never seen a milkweed plant before. I used to live in Philadelphia and now live near Houston. Poor areas for sightings perhaps?

    1. Not really:



      - but you'd have to get away from TYWKIWDBI and your computer and go outdoors.


  6. They're here (Houston), but don't look like the northern species. (See above). They are a species of disturbed environments, like recent construction. Look for the sunflowers or passionflower vines and you'll find them.


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