Lots of people know milkweed (Asclepias spp.) as the plant that Monarch butterflies need, or recognize its unique seed pods which open to release many silky little parachutes in the fall and early winter – but there’s so much more to this versatile and essential native plant. Let’s explore some important milkweed species, the insects that rely on them, how to eat them as a vegetable, and more!
Out of 70 or so species of the Asclepias genus native to North America, there are about 13 native to New York State; at least three of these are known to be naturally present here in St. Lawrence County. Common milkweed (A. syriaca) is the most prevalent of these, thriving in successional fields, disturbed areas like roadsides, and occasionally in forest clearings.
Next is swamp milkweed (A. incarnata), in particular the ‘western’ variety (A. incarnata var. incarnata). As the name ‘swamp’ suggests, this species prefers low, wet areas like marshes and swamps, edges of ponds and streams, and poorly-drained parts of fields.
Finally, there is forest milkweed or poke milkweed (A. exaltata), which grows mostly in deciduous forests, especially along roads and paths. It’s not as common as the other two in our area, but you might find some.
Some of the species that are native to other parts of NYS might also be found in our area, due to human cultivation. A couple of these include whorled milkweed (A. verticillata) from the Hudson Valley, Catskills, and Greater Niagara regions; and butterfly weed (A. tuberosa), very popular with gardeners for its striking orange blossoms which are unique among milkweeds. Its native range reaches most of the state, but might not normally come as far north as St. Lawrence County.
Every species of milkweed provides an essential food source to pollinator populations. They attract all the usual suspects – Bumblebees, Honey bees, other native bees and wasps, and Hummingbirds – as well as supporting lots of butterflies and moths.
The native Asclepias in our area, especially common and swamp milkweed, support 12 species of lepidopterans (butterflies and moths). Milkweed is the sole food source for the larvae of Monarch butterflies (Danaus plexippus), but that’s far from all. The Unexpected Cycnia (Cycnia inopinatus) and Milkweed Tussock Moth or Milkweed Tiger Moth (Euchaetes egle) also exclusively rely on milkweed as a host, and it’s crucial to the Delicate Cycnia or Dogbane Tiger Moth (Cycnia tenera) and Lined Ruby Tiger Moth (Phragmatobia lineata) as one of only two or three host plant genera that they use.
Anyone who has grown or been around milkweed has likely seen some other reddish-orange and black insects that frequent these plants. One is the Milkweed Longhorn (Tetraopes spp.), a type of beetle that has specialized to feed on milkweed plants. Its larvae bore into the roots of the plant to feed and overwinter there, and when the adults emerge in late spring they eat the leaves. There are at least three species in the eastern United States – they are very similar, but vary in their amount of black spotting.
If you have seen dense clusters of orange-and black insects on a plant, they were likely Large Milkweed Bugs (Oncopeltus fasciatus). The ½ to ¾ inch long adult insects will remain hidden for most of the year. They emerge for about a month when milkweed develops seed pods, and swarm on the plants to feed on the seeds and reproduce. This typically does no significant damage to the milkweed plant, and since the bugs are highly specialized to this diet, they should not harm any other plants. It’s generally advisable to leave them alone, as they are just another native species that milkweed supports; but if the gardener finds it necessary, consider controls that won’t harm caterpillars.
There’s a fascinating common thread here among insects that feed on milkweed. A majority of them, including Monarchs and some other lepidopterans, as well as this beetle and bug, respectively, use the same orange-and-black color scheme for their aposematic coloring – a pattern meant to warn predators that they are poisonous or just taste bad. They all get this defense mechanism from eating milkweed, and concentrating the toxic substances it produces for its own defense in their bodies.
Despite long-standing misconceptions about its level of toxicity, common milkweed and some of the other broad-leaved species are safe for human consumption as long as they are cooked; Native Americans used them as a food source since well before European settlers arrived. The plant does contain some toxins, including a cardiac glycoside, but light cooking is enough to break those toxins down to safe levels for most people. Young leaves, shoots, flower buds, and immature pods can all be blanched and eaten as a vegetable, while more mature flowers take on a sweeter taste, and can be used in things like syrups.
Some sources still claim that multiple rounds of boiling are required to render milkweed safe to eat, but many people in the foraging community have shown that this isn’t necessarily true, eating lightly cooked milkweed on a regular basis with no ill effects. Still, some people are more sensitive to its effects, and as with any wild food, it’s advisable to use caution and do your research. As with foraging any new plant, try small amounts first to observe how your body responds.
- Note: Milkweed is toxic if eaten raw, and the sap may also cause skin irritation. Narrow-leaved species, such as butterfly weed (A. tuberosa), contain much higher levels of the same toxins, and are not safe to eat, even if thoroughly cooked. Milkweed is also extremely toxic to some animals such as dogs, possibly even when cooked enough to be safe for humans.
When harvesting from the wild, it’s important to follow general rules of responsible foraging:
- only harvest from well-established populations,
- leave enough for the plant or patch to recover, and enough for the insects or other wildlife that depend on it
- only take as much as you will use.
Putting these in practice will mean different limits for each type of plant. Milkweed is pretty resilient and can even re-sprout from the base a few times in a year, if shoots are harvested or a patch has the misfortune to get mowed over.
It is also important to have positive identification when harvesting milkweed to eat, because it does have a look-alike. Dogbane, another plant in the same family, can be confused for common milkweed when young, but is more toxic and inedible. There are ways to tell them apart, though; for example, milkweed stems are slightly fuzzy while dogbane is smooth, as well as other differences like branching pattern and flower arrangement, which become clear in more mature plants.
Some other ways milkweed can be used besides food involve the fine fluff meant to carry its seeds on the wind. These tufts of fluff attached to each seed are sometimes referred to as silk or floss, or their more technical name, coma. Whatever you call them, these fine fibers produced in mature milkweed seed pods have seen various uses by humans. During World War II, children were encouraged to contribute to the war effort by collecting these pods, so the silk could be used for stuffing life vests. Now, they are still sometimes used as a filling for pillows and comforters.
The most versatile species to cultivate in the North Country is probably common milkweed, since it is native here, and is the most tolerant of varied conditions. It’s also a great option because of its attractive blossoms and their strong sweet fragrance, as well as its potential as a vegetable. Here in the pollinator garden at the Extension Learning Farm, it has bloomed from June 20 through July 15 in past seasons, then seed pods appeared about a week later. Other sources state it can bloom anytime throughout June, July, and August. It prefers full sun and moist soil, but otherwise tolerates a wide variety of soil types. Since it naturally spreads by rhizomes, producing clones of itself, a recommended method of propagation is to cut and transplant some rhizomes in the spring. Of course, you can also grow it from seed if you prefer. Enjoy!
Resources:
- Asclepias syriaca (Common milkweed) | Native Plants of North America
- Asclepias tuberosa (Butterflyweed) | Native Plants of North America
- Search Results – NYFA: New York Flora Atlas
- USDA Plants Database Plant Profile General
- Foraging and Cooking Milkweed
About pollinators and other insects:
- Plant Information – Native Plants Finder
- Milkweed Longhorns
- Milkweed Bug | NC State Extension Publications
Amalia Kanitz grew up on a small farm in De Kalb NY and is currently a rising sophomore at St. Lawrence University. She was involved in 4-H for many years, and participated in horticultural knowledge competitions up to the national level. This summer, she is the SLU Public Interest Corps Garden-to-Table intern at CCE, helping with the Master Gardener Volunteer and Master Food Preserver programs. Amalia enjoys making visual art and music, learning about native plants and foraging, and appreciating the little things in nature.