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| Asclepias syriaca whole plant |
Asclepias syriaca is a member of the Apocynaceae (dogbane family) [2]; several genera of this family produce latex, including Asclepias spp. [3]. Asclepias syriaca also produces some chemicals (specifically cardiac glycosides) which can be quite toxic to humans and livestock, so although parts of the plant are edible, the seed pods and mature leaves are not to be consumed [4]. Seriously, the effects go all the way up to coma [5] (although it would take a very large dose to experience such serious effects [4]), don't just go chowing down on this plant despite it being listed as edible with various sources. The edible portions include the young shoots and the flower buds [4,5,6,7]. Given that they are edible, I had a taste of the flower buds. They were acceptable, but sort of bland with a vague hint of generic 'green' taste; they may be better cooked than they were raw, but some other reports suggest that though edible and nutritious, they're not really much to write home about flavour-wise [5].
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| Asclepias syriaca inflorescence |
Asclepias syriaca has a long history of use in traditional medicine for a wide range of ailments [5].
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| Asclepias syriaca inflorescence |
This plant is evidently much more palatable food to monarch butterflies (Danaus plexippus); Asclepias syriaca is the primary food source of the monarch butterfly larvae [4,5,7,8,9,10,11]. The cardiac glycosides apparently help confer a protection to the larvae and caterpillars by making them toxic [5], which is pretty cool. So I guess if you can't make a poison yourself, get poison elsewhere and incorporate it into your flesh. Pretty hardcore. Some other insects that favour this plant as a food source include the large milkweed bug, common milkweed bug, red milkweed beetle, blue milkweed beetle, bees, wasps, butterflies, moths [5,6,8,9,10]. Anecdotally, I frequently see ants collecting nectar from this plant, although I am probably witnessing nectar-robbing, as ants usually don't provide pollination services (pollen doesn't stick to their armour much, so it doesn't get transferred).
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| Asclepias syriaca being visited by ants - photo I posted in the previous post about this species |
Anyway, my point here is that although Asclepias syriaca is edible, it's not all that tasty, so you're better off leaving it to the monarch butterflies and the other insects that prefer it -- especially considering that the monarch butterfly is potentially under threat and currently being assessed for potential endangered status [12]. I will say (again, purely anecdotally), that I have seen none of the usual monarch butterflies that I am accustomed to seeing at my family's land in the Upper Gatineau; in spite of this, I am reserving judgement on the question of the species' endangerment until the assessment report is released.
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| Asclepias syriaca inflorescences |
Asclepias syriaca is a serious nectar-producer, and it certainly announces that fact loudly; it has a very strong, sweet, pleasant scent that is strong enough to be easily perceptible to humans. Given the large quantities of nectar it produces, it's no surprise that it is a very attractive plant for a whole lot of insects.
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| Asclepias syriaca - perfect flower close-up - photo posted in my previous post about this species |
The flowers of Asclepias syriaca are bisexual or perfect, meaning that they have both male and female parts [6]. This species is primarily outcrossing, meaning that it relies on pollen being brought from another individual in order to reproduce successfully [6]. Good thing it attracts so many willing assistants with the nectar reward it offers for their trouble!
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