Wednesday, June 30, 2010


Milkweeds are champions at attracting a wide variety of insect species. There are the casual visitors that come to the plant just for food, as well as an entire menagerie of species that are intimately tied to milkweeds for their survival. When out walking, I always check the milkweeds to see what animal life can be found. A variety of tiny flies were visiting this bloom.

Common Milkweed, Asclepias syriaca, is a plant of the open fields. Many people tell me that milkweeds growing in the field are a sign of mismanagement. It seems to confuse them when I suggest that the presence of milkweeds only signifies poor management if you are managing for a condition that doesn’t include milkweeds. Milkweeds in a pasture or hay field indicate poor management, but milkweeds in a field being managed for diverse native grassland species do not, so don’t use that as an argument that I’m not caring for my fields. This is the point at which I turn the conversation towards the weather, which my daughter says is the only subject I’m capable of handling in social situations.

The fully opened milkweed blossom is a nectar factory that feeds a multitude of different species. I’m especially interested in pollinators and spend a lot of time watching the native bees. A few weeks ago I was with some backyard fruit growers who were lamenting the decline of the European Honeybee and wondering how their flowers would be pollinated if things didn’t improve. When I suggested they try managing for native bees that could provide the same pollination service, they looked at me as if my hair had caught fire. Apparently, any acceptable substitute had to share the honeybee’s ability to work on demand as well as produce a marketable byproduct.

This grasshopper is eating a portion of the flower. Milkweeds contain steroid glycosides and other toxic substances that make the plant unpalatable to all but a few species that have evolved to deal with the toxins. The concentrations of toxins vary throughout the plant, so the grasshopper may be feeding in a less dangerous area. The tiny white spot on the grasshopper’s back is the empty skin of a tachinid fly egg. The larva has recently hatched and made its way inside the grasshopper, where it will feed until ready to pupate. The grasshopper will not survive the activities of this parasite. Perhaps milkweed toxin is a remedy to tachinid fly infestation.

The flowers are even attractive pre-bloom. Like many plants with multiple blooms, the flowers develop and open in succession, so the blooming and pollination activities occur over a long period.

The underside of the Common Milkweed leaf reminds me of a thick carpet. You certainly wouldn’t imagine these tough, hairy, poisonous leaves to be something edible. I wonder what was after these plants that made them evolve such a collection of defensive mechanisms.


  1. Quite an interesting post today, Steve. I always learn something when I visit. You crack me up with your sense of humor. So, how IS the weather? I've had similar responses when I've suggested similar ideas to people. But then again, I see beautiful flowers where others see weeds! ~karen

  2. Milkweed seems to just pop up out of nowhere here!!! I simply love the blooms and the sent is so nice floating on a summer breeze!!! I have eaten the pods while real small cooked and they taste something like asparagus...I'm am still alive....;} They are supposed to be edible...what do you know on the subject!! """ Oh I would never say you where not caring for your fields""" :} :}

  3. Hi, Karen. The weather is great. Thanks to an inflow of Canadian air, 70's and sunny tomorrow. Warming for the weekend, but no rain in sight. Hurricane Alex may swing up and pay us a visit next week. Am I not a brilliant conversationalist?

    grammie g - Milkweed sprouts easily from seed and established plants send out long rhizomes that can put up shoots several feet away. There's not much prettier than a milkweed patch.