By Barry Cottam

Invasive dog-strangling vine. Photo: Brewer Park Community Garden

Invasive dog-strangling vine (Cynanchum rossicum & C. louiseae) is being removed throughout Ottawa. Photo: Brewer Park Community Garden

Dr. Steven Chatfield’s presentation at the OFNC monthly meeting on June 5 was the result of a long molecular chain whose first component was his visit to the Fletcher Wildlife Garden the previous summer. Steven had come to the FWG to ask about collecting some seeds and find out how we dealt with dog-strangling vine, something that confronted him in good supply when he took over an abandoned garden near the biology building at Carleton University.

He had the good fortune to run into a particularly enterprising volunteer, Lynn Ovenden, who leveraged his query into a visit for FWG volunteers to his new research garden and the nearby greenhouses that house plants that make interesting chemicals, and he even offered to talk to the OFNC about them. We learned yet another way to handle dog-strangling vine: use a front-end loader. Alas, while it worked for Steven, it’s not something we’re ready to try yet at the FWG. He’s got us thinking, though.

Steven’s presentation will get you thinking about the microscopic and fascinating universe of plant defences. Anyone who thinks of plants as passive because they are sessile doesn’t get what’s going on: it’s a chemical war out there in Plant World, with tens if not hundreds of thousands of chemicals “talking” to one another in complex and myriad ways. These chemicals are produced primarily as secondary lines of defence in plants’ efforts to ward off attack from herbivores and competing plants.

Peppermint owes its aromas to terpenes, which also attract pollinators and warn insects/herbivores. Photo: Google

Peppermint owes its aromas to terpenes, which also attract pollinators and warn insects/herbivores. Photo: Google

Building on this, Steven went on to discuss the uses to which humans have put these defences. In human terms, plant defences have produced everything from medicines to hallucinogens, construction materials to perfumes, foods to the deadliest poisons. How humans over the millennia have steered their way through the plant kingdom to figure these things out is a topic for another day, although he does provide some hints at potential future uses. So click here and check out Steven’s presentation from the monthly meeting – you’ll learn a lot, find lots of things to follow up, maybe even get converted to studying botany, often and erroneously considered a modest cousin in the family of life sciences. Now, about that dog-strangling vine…

Postscript: The presentation ends with two references to TVO online videos; the url for Pain, Pus and Poison has been changed to