Eatin' Weeds

As the Museum’s botanist it is important for me to know not just how to identify plants but also how people traditionally and contemporarily use wild and weedy plants. Although I am familiar with the edible fruit and nut plants of the prairies (and am quite enthusiastic about eating them!), I have been less inclined to try the edible wild greens. The main reason behind my reluctance had to do with the fact that I wasn’t quite sure when and how to harvest and prepare said greens.  When I heard that an acquaintance of mine, Laura Reeves, offered workshops on how to prepare and eat wild edible plants (amusingly called “you can eat that?”), I determined that it would be beneficial for me to get some first-hand instruction.

One of the plants with a wide variety of uses is cattail (Typha spp.). First Nations traditionally ate cattails, which are also an important food source for animals like muskrats and geese. Our morning began by removing and munching on a few cattail shoots, which were crunchy yet tender and reminiscent of cucumber. We then proceeded to carefully dug up a few roots which we later washed to remove the starch; the wet starch was used later to make cattail pancakes. Cattail pollen can also be used as “flour” and the green flower heads (which we couldn’t try because there weren’t any yet) can apparently be eaten like corn on the cob.

We went on to harvest the roots of burdock (Arctium lappa), sweet cicely (Osmorhiza claytoni), caraway (Carum carvi), and dandelion (Taraxacum officinale), the spring shoots of milkweed (Asclepias syriaca), the leaves of basswood (Tilia americana), stinging nettle (Urtica dioica), lamb’s quarter’s (Chenopodium album), maple-leaf goosefoot (Chenopodium simplex), and stinkweed (Thlaspi arvensis), and the flowers of caragana (Caragana arborescens). With our buckets full of wild plants we went on to wash, rub, scrape, chop, roast, boil, steam, and bake our plants into a delicious meal of:

Basket of washed dandelion roots ready for roasting.

For the last several months I have been helping to organize the 23rd North American Prairie Conference (NAPC) (click here for conference details) which will be held at the University of Manitoba from August 6-10. This is first time that this conference has been held in western Canada (it is usually held in the mid to western U.S.). I’m looking forward to learning more about prairie conservation and restoration initiatives from other Canadians  as well as our American neighbours. This conference will feature a number of prominent prairie enthusiasts including Canadian authors Sharon Butala and Candace Savage as well as Dr. Wes Jackson from the Land Institute in Kansas and Dr. David Young from the Natural Resources Institute in Winnipeg. Ojibway elder David Daniels will be talking about Canada’s native plants and their traditional use.

Conferences like this provide a great opportunity for professionals to meet and exchange information that will assist with their work. But it is also a chance for people who are just concerned about prairie conservation to learn more about these beautiful and intricate habitats that are now almost gone. Hope to see you there!

On occasion I’ve met people who would ask, in reference to a plant that I was studying, “what good is it?”. I was initially somewhat baffled because I assumed that most people knew that plants are needed for an ecosystem to function properly, and that since ecosystems provide humans with clean water and air, they are important. But sadly many people view species from a complete utilitarian viewpoint, assuming that if you can’t eat it or cut it down to make furniture, it is useless and therefore expendable. One argument for the conservation of all plants is that we simply don’t know which ones may yield chemicals potentially useful to humans. What is considered a useless plant one day could be a life saver on another.

The Pacific Yew tree (Taxus brevifolia) was long considered a “weed” by foresters. In the 1960’s an extract from this species called paclitaxel was found to kill cancer cells. The drug Taxol was approved by the FDA in 1992 and is now a commonly used in the treatment of ovarian and breast cancer.

It was nice to hear that another much maligned plant, namely the common dandelion (Taraxacum officinale), is also being investigated for its anti-cancer properties (read the CBC article here). An extract from dandelion roots dug out of the lawn by graduate students at the University of Windsor was found to kill leukemia cells but not healthy cells (see details here). I find it very ironic that a plant that people have spent thousands of dollars trying to get rid of (in the process of doing so exposing themselves to potentially cancer-causing toxic chemicals) may actually hold the key to curing a form of cancer: leukemia.

What people may not know is that dandelions have actually been used medicinally in ancient China and in Europe since at least the 11th century for its diurectic and detoxifying properties. Modern herbalists prescribe dandelion root for a variety of ailments. The dried roots are typically harvested, dried, and brewed to make a tea that tastes somewhat like coffee. Dandelion leaves are also edible and very nutritious, being especially high in vitamins A and C. You can collect the young tender leaves and throw them in a salad (just make sure they come from a lawn that hasn’t been doused with herbicides!). The roots and flowers can also be made into alcoholic beverages such as dandelion wine and root beer. Other “weedy” plants that are edible include burdock (Arctium spp.) (its roots are edible) and Lamb’s-Quarters (Chenopodium album) (it’s leaves are very nutritious). Burdock seed heads were actually the inspiration for velcro!

Ralph Waldo Emerson said that “a weed is a plant whose virtues have not yet been discovered”. It’s time for us to appreciate the virtues of weeds like the dandelion!

Nature preservation is often seen as something that is “nice” for people to do if they can afford to as it really isn’t all that important for the survival of humanity. Increasingly though scientific research is revealing that this attitude is based on an incomplete understanding of how the world works.

For the last several years I have been studying the interactions between insect pollinators and wild plants. I’ve discovered that plants do not depend on just one pollinator; they are pollinated by multiple species of insects. In turn, these pollinating insects depend on a multitude of plant species to help them survive. The end result is an intricate web of interactions, much like a social network, where the health of the entire system depends on the health of each individual species. If any species are lost, the web becomes weakened and less resilient in the face of unusual events, like severe droughts, and climatic changes. Computer models suggest that the loss of species engaging in the most interactions (such as bees) will result in a more rapid cascade of secondary extinctions than species with fewer interactions (1).

Measures that protect nature can also help to save human lives. Pesticides can negatively affect human health; measures that restrict or control their use are therefore of direct benefit to humans (7). Conservation of wetlands can help reduce flooding and improve air and water quality, outcomes that also help protect human health. Our species needs to protect and find ways to work with, not against, natural systems as doing so is ultimately in our own self-interest.

References

1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691904/pdf/15615687.pdf
2. http://nature.berkeley.edu/kremenlab/Articles/Value%20of%20Wildland%20Habitat%20for%20Supplying%20Pollination%20Services%20to%20Californian%20Agriculture.pdf
3. http://www.ufz.de/export/data/1/22686_Potts_et_al_2010.pdf
4. http://www.uoguelph.ca/canpolin/Publications/Poll_decline_ENG_MC3-1.pdf
5. http://onlinelibrary.wiley.com/doi/10.1111/j.2007.0030-1299.16303.x/abstract
6. http://www.jstor.org/discover/10.2307/4543402?uid=3739408&uid=2129&uid=2&uid=70&uid=3737720&uid=4&sid=47698832505157
7. http://www.hartfordhospital.org/Portals/1/Images/22/PerinatalSymposium2011/Pesticides%20and%20Health%20Risks.pdf

For the last several years I have been studying the pollination ecology in Birds Hill Provincial Park focusing specifically on the rare Western Silvery Aster (Symphyotrichum sericeum) plant. I discovered that this species is self-incompatible (meaning it can’t fertilize its own eggs), and visited by a wide range of insect pollinators, including both flies and bees.

I also discovered that although this rare plant competes for pollinators with the much more common Showy Goldenrod (Solidago nemoralis) plant, a negative effect on seed production only occurs when their blooming periods overlap.

My first thought was that reducing the number of Showy Goldenrod plants in the community would result in more insect visitations for the rare plant but then I reconsidered as this did not intuitively seem like the right course of action. I wondered if removing plants would actually end up reducing the local insect population by reducing the quantity of nectar available. Perhaps the plants aren’t really competing at all but rather working together to support their mutual pollinators throughout the year. I also considered that any plant species that completes its flowering before Western Silvery Aster begins blooming would not be competing with it for pollinators at all. In fact, you could argue that the common plants facilitate insect visitation to the rare plant by providing nectar to their shared pollinators. Purple Prairie Clover provides nectar to Western Silvery Aster’s pollinators in July.

I decided to test this hypothesis by recording the insect visitors to other plant species before Western Silvery Aster even begins to flower. So far I have obtained some interesting results. One of the most important insect visitor species, a bumblebee (Bombus bifarius), was observed visiting five species of plants in June and July in addition to Western Silvery Aster. A second species, a bee fly (Anastoechus barbatus), was observed as early as July 12, pollinating three other plant species. It appears that when plants share pollinators, staggered flowering helps to (a) decrease competition, and (b) sustain pollinating insects throughout their active season.

I think that there is a tendency for western scientists to place too much emphasize on competition when interpreting the results of their research. We need to remember that co-operation, if it results in both species increasing their offspring, is also a beneficial strategy for survival.

For the last two years I have been searching for four species of rare Bugseed (Corispermum spp.) plants. Historically these plants were found in sand dunes and along the beaches of Lakes Winnipeg and Manitoba. Unfortunately there were very few recently collected specimens; most had been collected over 40 years ago. Attempts to determine the rarity status of these plants were hampered due to this lack of information.

During my field work I relocated fewer than half of the historical populations of Bugseeds indicating a substantial loss of habitat. In some cases, dune stabilization appears to have resulted in the loss of habitat for these species, which grow in bare sand. Flooding along the Red River and on Lakes Manitoba and Winnipeg in 2010 and 2011 may have also caused the loss of habitat as several historical populations had been previously found on the beaches, dunes and sandbars along the south shore of these lakes. Balancing out the losses a bit was the discovery of seven new localities in the province including a very large population of Hairy Bugseed (C. villosum) in the sand dunes in Grand Beach Provincial Park.

Unfortunately, I could not locate any Pallas Bugseed (C. pallasii) at the three sites where it was historically found although I did find some American Bugseed (C. americanum) at two of the sites. Pallas Bugseed is still present in other Canadian provinces so it is not extirpated in the country. It is possible that this species spread into Manitoba from other provinces where it is native along railways and then subsequently disappeared as more hardy weeds took over the habitat. As the seeds of these species are quite long lived and tolerant of burial, Pallas Bugseed may still be here in the province, hiding in the soil and waiting for the right conditions to germinate.