Capital Daily

Southern Vancouver Island's Exotic Plants

Episode Summary

We have a conversation about the various types of plant life that thrive in our mild climate. Also, we explore if we should focus more on preserving our unique native species as climate change presents an uncertain future.

Episode Notes

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Episode Transcription

Disclaimer: This conversation has been edited for length and clarity

Jackie: My name is Jackie Lamport. Today is Tuesday, May 11th. Welcome to the Capital Daily podcast. Southern Vancouver Island is rich with unique plant life. Native and non-native species thrive in the warmer, drier climate. We speak to Forest Ecologist Andy MacKinnon about the species that grow here and why it's important to preserve our native plants.

Jackie: The windmill palm, known scientifically as Trachycarpus fortunei, has become a regular fixture in certain areas on Southern Vancouver Island, and surprise surprise, the tree is not actually native to the ecosystem. The tree hails from parts of China, Japan, Myanmar and India. It is one of the hardiest palms in the world, with an adult specimen being able to withstand temperatures of up to -20 degrees celsius. Given the mild winters on Southern Vancouver Island, the plant adapts nicely here. The fact that a palm tree grows so successfully in Canada is clearly a bragging right for us on the Pacific Northwest, but the incredible ecosystem we’re so lucky to call home has much more to offer. Today’s conversation is with Forest Ecologist Andy MacKinnon. He and I discussed the native and introduced species that thrive here and highlight some of the unique plants from the island at risk.

Jackie: Andy, thank you so much for taking some time for us today.

Andy: Happy to be here, Jackie. Thanks for the invitation.

Jackie: I want to start by talking about some of the plants that are commonplace, and they become kind of an identifier of the island but aren't actually native. My mind immediately goes to the blackberries, which I recently learned were not native.

Andy: Oh yes, we have a wonderful climate here for people and invasive species. Certainly, the blackberries you enjoy so much, but many other common shrubs like a scotch broom, gorse, spurge, morel. And then a lot of smaller plants, like dandelions, a lot of the little things that look like dandelions, a lot of mustard family plants. So there were lots and lots of introduced species around Victoria.

Jackie: Are most of those intentionally introduced or accidentally?

Andy: Well, it's really a mix of both, and a lot of them have been accidentally introduced. We have also accidentally introduced spiders, for example, and fungi, but we're talking about plants today. Most of the plants, the introduced plants, and certainly the introduced invasive plants were introduced accidentally. But we have a lot of introduced plants that people have deliberately introduced, which would include most things probably in your garden. A lot of our boulevard and yard trees, fruit trees, shrubs and things like that, that we quite enjoy.

Jackie: One of the types of plants that we have purposely introduced is the different types of palm species on the island. Can you first just explain a bit more about the different species that we do have and where they come from?

Andy: Well, there's a number of different palm species that all come from warmer, drier climates, a number of them from the Middle East, some from North Africa. One of the reasons people like to grow them here on southeastern Vancouver Island is because they can't. So there aren't a lot of climates in Canada that would support palm trees and southeastern Vancouver Island, and the Southern Gulf Island happens to be one of those areas. So a lot of gardeners will take that either as a challenge or as a chance to perhaps show off to relatives in eastern Canada that they're living someplace where you can grow palm trees. But there's a number of different species that people grow on Southeastern Vancouver Island.

Jackie: Let's move on to the monkey puzzle tree. What can you tell me about those ones, and when were they introduced to the island?

Andy: Well, the earliest monkey puzzle trees that are the oldest ones I've seen are over 100 years old. So they were introduced sometime near the beginning of the 20th century; there may be older ones that I haven't seen yet. They're a species that I've observed in Chile and Argentina and a beautiful, beautiful specimen tree. The one that does very well in our climate, a really exotic-looking tree. A lot of gardeners wanted to have something in their garden or in their yard that can demonstrate their progress as gardening or, perhaps, show an unusual plant that other people don't have in their gardens. I think a number of people I've talked to that planted monkey puzzle trees for that reason. It's just such a spectacular and different and weird-looking tree. As I mentioned, I've been fortunate enough to see woodlands have monkey puzzle trees in their native habitat, and it's quite a spectacular sight.

Jackie: Yeah, they're definitely eye-catching it. They're so unique. In my opinion, it's probably one of the most unique plants that I've seen on the island.

Andy: Well, you can imagine forests of them in a landscape with volcanoes and lots of parrots and parakeets.

Jackie: Sounds wonderful.

Andy: It is, and it's a lot more enjoyable than simply seeing a single monkey puzzle tree in the middle of someone's yard.

Jackie: I bet.

Andy: It's a nice surprise in Victoria too.

Jackie: Yeah, for sure. What are some of your favourite exotic plants that have been introduced to the island?

Andy: Well, you mentioned you were a fan of the Himalayan blackberry. Now, I love blackberry pie and blackberry wine as much as anybody. And I'm going to incur the wrath of a lot of your listeners by saying so because I've also spent an awful lot of time working with other people to try and clear blackberry from natural areas where its growth excludes the native plant species. So if you're picking a few blackberries from it, making some wine or something like that, it’s a very nice plant. But like some of the other introduced species, it can be very invasive to the point where it displaces our native plants. So maybe I better not say I like blackberries. Certainly, a lot of the fruit trees are favourites of mine. Gosh, introduced species. Well, everybody's got their favourite spectacular garden plants. Even though we have spectacular native plants in British Columbia, very few people use them in gardening. There are a group of people who garden with our native plants and have some of the most spectacular gardens, I think around Victoria, but most people don't. Most people have introduced plant species dominating most or all of their garden and introduced grass species making up their lawn.

Jackie: Wow, grass too. Okay, interesting.

Andy: Well, there are native grasses, but a lot of our native grasses are bunch grasses and not particularly well suited to making the green lawns that a lot of people want to drive tractors on.

Jackie: Yes. I will say I think one of the favourites that is the least controversial is probably the cherry blossom tree.

Andy: Yeah, and that's extraordinarily popular around Victoria. Even introduced tree species will bring with them oftentimes other species. I'm the past President of the South Vancouver Island Mycological Society, the mushroom club. And every late summer and early autumn here in Victoria, there are lots of news items about the death cap mushroom. The death cap mushroom, the fungus that produces that mushroom grows attached to the roots of introduced European trees. So the people who brought the hornbeams and the English oaks and sweet chestnuts here, in a few cases, brought with them the fungus that produces the death cap mushroom. So sometimes, these introduced species will bring other species along with them.

Jackie: That was actually going to be my next question. What are the dangers of introducing species to our environment? Is there any other examples that you have?

Andy: Well, I think the main danger is that some of these introduced species are very invasive. So sometimes, people think all of our introduced species are invasive. But, for example, people use the example of windmill pumps. We're not concerned about windmill palms taking over our parks and displacing our native vegetation. It's the species like broom, spurge, laurel, and blackberries that can be very invasive and can cover 100% of the ground and exclude our native plants. That's probably the biggest danger. I know people will think of things like the introduced death cap mushroom that came with these trees as a danger to human health. But I think a much greater danger in a lot of ways is the danger to our native vegetation and ecosystems posed by these introduced invasive plant species.

Jackie: Yeah, I could see some people not necessarily seeing the value in protecting our native species. Just as you know, things evolve, and we introduce new plants. What's the importance? What's the danger if we neglect protecting our native species?

Andy: Well, I think that the important thing, for me at least, is to think of each species. We're talking plant species here, right?

Jackie: Yeah.

Andy: But you could make the same argument for animals or fungi. Each of these plant species is in itself a little ecosystem. It has fungi and probably bacteria and other creatures that grow with its roots. It has fungi that grow inside, in its stems and its leaves. It has pollinators that depend upon these plants. And for some of the moths and butterflies, there's a very close relationship with individual plant species or genera. We have flowers that produce fruit, that's an important food for a lot of animals around here. So if you lose a plant, you don't just lose that plant; you lose all of the other species of plants and animals and fungi that are part of that plant's ecosystem. You begin to lose the biodiversity, the diversity of species ecosystems and processes in an area. Anytime people move into an area, they're going to change it. So the concern for a lot of people is to try and keep some good examples of our native plants.

Jackie: That actually kind of brings me to another question I wanted to ask. During some research for this episode, I came across a past controversy over promoting the sale of planting palms instead of native species. And this is specifically referencing an annual palm tree sale that was supposed to happen in Oak Bay. This was back in 2012, but it was cancelled after the council denied access to municipal grounds, citing that the native Garry oak should be taking precedence. “We shouldn't be encouraging people to plant palm trees, and we should be encouraging them to plant the Garry oak.” Is this something that's valid?

Andy: I think it's a spot-on argument, Jackie. I think we need more people paying attention to our native species for all of the services they provide here for being part of our native flora. For all of the species that depend upon them, it would be a sad day if Oak Bay lost its oaks, let's say. Certainly, there are a lot fewer oaks in Oak Bay now than there were when Europeans first arrived and almost certainly, there will be fewer in the future. So we don't need to encourage people to replace our native flora with introduced species; quite the contrary. You know, a couple of native plant nurseries around Victoria provide exceptional service, but they're dwarfed by the number of introduced species nurseries. So I think there are groups like the habitat acquisition trust, who have a lot of expertise in helping people grow native plants, and making their yards at least as spectacular as if they were growing introduced species.

Jackie: I want to focus on the palm tree because that's where the point of controversy was. The palm tree is something that, like you said, there's a lot of reasons people want to plant it. Number one, it looks cool. Number two is just, “wow, we can plant palm trees in Canada.” Is that something you've noticed has become more popular, and more people are seeking to grow those plants in their gardens or homes?

Andy: Not that I've noticed any great trend, Jackie. People have been planting palms in Victoria since at least the middle of the 20th century and perhaps probably before that. It demonstrates that we can perhaps, even if climate change projections are accurate, this might become a better place for growing palms in the future. But that's no reason for displacing our native vegetation. A palm tree here, a palm tree there; it's not going to be invasive, and it's not going to displace the native plants in Uplands Park, for example. Not like scotch brooms might do or some of the other introduced species.

In Canada, Garry oaks grow only on southeastern Vancouver Island and the Southern Gulf Islands. It's like arbutus in a lot of ways and a few dry places on the mainland. It's characteristic and distinctive for this part of the world in all of Canada. It's those special things about this climatic zone, these ecosystems that I'd like to see people valuing a bit more, not just protecting but promoting. So yeah, I agree 100% with the Oak Bay council that it's time that people spend a lot more time planting Garry oaks and a lot less time planting palms.

Jackie: You mentioned the Arbutus tree, and that's one that I wanted to mention as well because it's having some trouble this year. Can you explain a little bit of the troubles that it's facing?

Andy: The Arbutus trees throughout the rains in British Columbia, but especially on Southern Vancouver Island, are being attacked by fungal parasites called leaf blights that damage and kill the leaves. Arbutus trees normally have leaf plates, but they don't cause as much damage as we're seeing right now on Southern Vancouver Island. This happened again about maybe five or six years ago and some of the Arbutus trees at the time were so damaged that they died. And I fear that the Arbutus we're seeing now with the attack of the leaf blights, it's certainly going to defoliate a lot of them. Some will recover, but some will die. It’s a real problem, and people can see it in a lot of areas in Southern Vancouver Island. You probably see the Arbutus trees with the leaves that are all brown and curled up, and that's leaf blight fungal parasites killing the leaves. The tree will be defoliated, and if the tree is healthy enough, it should be able to grow a new crop of leaves and carry on if it doesn't get defoliated again. But if it's at all stressed, some of the trees may very well succumb to this blight.

Jackie: Overall, is this tree species at risk?

Andy: You know, I wouldn't have thought so, but there are lots of surprises out there with what I expect is evidence of a changing climate in this part of the world. We saw it first with the death of an awful lot of our Western red cedar trees; that was kind of predicted. This past year, we've been losing a lot of Douglas fir trees on some of the Southern Gulf Islands and a lot of our beautiful trees, obviously on Southern Vancouver Island. Some of these things, for example, the cedar die-off was predicted based on climate projections. Other things are coming as more of a surprise. I would put the leaf blight in that category. Also, there's been a massive decline of Yellow cedar from lower subalpine elevations from the central coast of British Columbia to Southeast Alaska on Haida Gwaii. So lots of surprises out there as the climate is changing, things that we might not have anticipated.

Jackie: Given that and given the fact that Victoria does seem to like our exotic species, do you think that it's time for a shift to focus more on our native species and to try and start preserving them and protecting them because they are at risk?

Andy: Yes, absolutely. I think everybody should be doing more to promote the use of our native species. But we also have to watch quite carefully because it's entirely possible in 50 years that if climate projections are correct, that this may not be a good place for Western red cedar or Douglas fir to grow. So for now, I think more people should spend time learning about our native flora, growing our native plants in their yards and in their gardens. And if they're really enthusiastic, working with local friends and natural history societies, to remove some of these invasive species, especially from our protected areas and parks.

Jackie: I'm assuming you're begrudgingly hinting toward the blackberries.

Andy: The blackberries, you know, it's always easier to get groups of people to remove spurge, laurel gorse and broom than it is to get groups of people to remove blackberries.

Jackie: It's bittersweet. They're a nice snack.

Andy: Well, I think for two reasons. One is indeed they're a very nice snack. The other is I've never emerged from blackberry removal adventures without blood all over me. So it’s a difficult task.

Jackie: I can imagine. Well, are there any other native species that you wanted to mention that we're at risk?

Andy: I think like a lot of people interested in plants. In this part of the world, it's really hard to beat the spectacular species of the Garry oak meadows. And Garry oak meadows used to cover a lot more of Southern Vancouver Island than they do today. One estimate is that about 97% of the range to these oak meadows is gone now. I happen to think that Garry oak is just a gorgeous tree. They’re craggy, spectacular, and beautiful, of course. They’re a lot of people's favourite trees. These oak meadows are open areas with Garry oak in them. The most magnificent, low elevation wildflower displays in British Columbia were camas fields described by some of the first Europeans to arrive here as looking like the lakes on hillsides with shooting stars. Western buttercup and a whole host of other species mixed in together; it’s hard to beat a Garry oak meadow, Jackie.

Jackie: Yeah, for sure. Thank you so much for joining the podcast. This has been an incredibly fascinating conversation. I'm a big fan of the plant life that we have on the island. It's such a unique place, and it's so awesome to see all of the different things that can grow here. So I really appreciate you taking the time to talk to me about them.

Andy: It's a very special part of the world, Jackie, and I think everybody listening has a good chance to help take care of it. So thanks for getting the word out.

Jackie: Thank you so much for spending some of your time with us today. If you enjoyed the show, please share so that other people can find the podcast. Also, rate review and subscribe so that you don't miss any episodes going forward. We post new shows every Monday to Friday. My name is Jackie Lamport. This is the Capital Daily podcast. We'll talk to you tomorrow.