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A palm tree seen in a park in Dartmouth, N.S. on Wednesday, Aug. 1, 2018. Halifax Regional Municipality planted the trees which are known to be hardy and to thrive in colder climes. THE CANADIAN PRESS/Andrew Vaughan
Andrew Vaughan/The Canadian Press
Atlantic Canada’s largest city has a new, and highly unlikely, tropical flavour.
Nine palm trees have been planted in four Halifax parks, although the jury is out on whether they can survive winter in a North Atlantic city known as the Warden of the North.
The parks, all on the Dartmouth side of Halifax Harbour, now feature cold-hardy palm varieties that can grow in more northerly climates of Asia such as China and Japan, or from areas of the continent with high altitudes such as northern India.
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The varieties include windmill and miniature Chusan palm, which are native to parts of Asia; needle palm, which is found in the southern U.S. states like Florida; and pindo palm, native to South America.
Municipal horticulturalist Chris Poole said aside from wanting to see if the palms can survive, it’s also part of his job to create public interest, and to encourage people to enjoy the city’s public spaces.
“I think by planting these palms around we’ve certainly achieved that and more,” said Poole, who noted windmill palms as a tall variety that look like a typical palm tree.
“They are certainly the ones that are creating the most buzz because when you take one look at them it just looks as if you are in a different part of the world,” he said.
Palms are grown elsewhere in certain parts of Canada, most successfully in Vancouver — one of the warmest of the country’s big cities during winter.
By contrast, the minimum daily temperature in Dartmouth averages minus -8 C in January and February, according to data from Environment Canada. And temperatures can dip well below that during typical cold snaps.
Ben Freeman, a post-doctoral researcher at the University of British Columbia’s Biodiversity Research Centre, is skeptical of Halifax’s palm plan although he “applauds the ambition.”
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He said the trees’ keys to survival in more northerly climates are cold and frost tolerance.
“Unless you actually go and try you don’t know whether they will survive, but I’m guessing that Halifax is too big a jump right now with current climates for palms,” Freeman said.
Still, Freeman thinks Halifax’s experiment is “pretty interesting,” because climate change has made colder places a little bit warmer.
“It really is true that you can plant palm trees a little bit further north than you used to be able to 50 years ago,” he said. “But I don’t have high hopes for the long-term survival of palm trees in Halifax.”
Egan Davis, lead instructor of horticulture training at UBC Botanical Garden in Vancouver, said he sees the windmill palm as the only species with a chance of surviving a winter climate like Halifax.
“Halifax has a pretty harsh climate even though technically the lows are not as cold as in other places where you can grow palms,” said Davis. “It’s just the harshness there, the storms and the amount of snow and the wetness over the winter.”
Poole acknowledges that cities such as Vancouver are in a “whole different climate zone,” but he points out that palm trees have been grown in different parts of Ontario.
“They [palms] are certainly being planted in some challenging areas and with a lot of success so we are hoping to do the same,” said Poole.
The supplier of Halifax’s trees is a Montreal-based company.
Sam Austin, a Dartmouth Councillor, said he has received a lot of positive public feedback about the palms.
“We’ve got a long tradition of showing off species that aren’t native as part of our parks program,” said Austin. “Not everyone has the chance to travel and now they can come see a palm tree without necessarily flying several thousand kilometres.”
Halifax has planted exotic species with various degrees of success in the past, including coffee and pineapple.
Most recently, an agave bloomed last month in the city’s renowned Public Gardens. The plant had spent most of its life in the city greenhouse before being transplanted outside this spring, drawing curious crowds.
Poole said the palm trees will likely require protective measures this winter. Those include mulching around the base of the trees to protect roots, wrapping the trunks, and tying the leaves into a tight mass to keep the crowns dry.
Poole said the needle palm can withstand temperatures in the -18 to 23 C range, while the windmill palms may need some kind of structure around them to protect from wind and severe temperature fluctuations.
However, the pindo palms will likely need to be housed in the greenhouse for the winter, Poole said.
If the experiment proves to be a success, Poole said there will likely be more palms doting Halifax’s landscape.
“I don’t think you are going to see them planted en masse by any means, but to have a focal point here and there in our park systems I think is the goal,” he said.
Spoiler alert, palm trees cannot grow unprotected outdoors in Canada except for a couple notable exceptions. These exceptions include zone 8 areas around Vancouver and Vancouver island or if you have a "micro-climate" in your zone 6/7 yard.
What about the rest of Canada? For 99% of the people reading this article, you are located in zone 5, 6, or 7 and you CAN grow palm trees outdoors using special protection techniques known as "zone-pushing". You can learn more about zone-pushing in our tutorial here: How to winterize cold hardy palm trees outdoors anywhere in Canada.
What kind of palm trees are suitable for zone-pushing? Truly tropical palms like a coconut palm will languish and almost certainly die during our harsh winters even when protected. To be successful, you'll need to select a cold-hardy palm which is rated for zone 7, 8, or even 9. Here are some of the best options broken down by difficulty:
ZONE 7 PALMS (BEGINNER)
Choose an appropriate well-draining planting site and protect for winter properly, and these palms have a very high chance of success. Zone 7 palms can be left unprotected late into the fall until double-digit negative temperatures approach. No need to plug in supplemental heating on a thermocube once protected unless temperature dip below -10C. (Save power!)
Needle Palm (Rhapidophyllum Hystrix)
Windmill Palm (Tracycarpus Fortunei)
Waggie Palm (Tracycarpus Wagnerianus)
Dwarf Palmetto (Sabal Minor)
ZONE 8 PALMS (INTERMEDIATE)
Zone 8 palms also have fairly high success rates, but are less forgiving to poor planting sites, improper and late protection. These palms cam handle a light frost, but be diligent to get them protected before even colder temperature approach. Keep these plugged into supplemental heating on a thermocube for the entire winter to ensure they are protected.
European Fan Palm (Chamaerops Humilis)
Pindo Palm (Butia Capitata)
Mexican Fan Palm (Washingtonia Robusta)
Saw Palmetto (Serenoa Repens)
Canary Island Date Palm (Phoenix Canariensis)
Sylvester Date Palm (Phoenix Sylvestris)
Mule Palm (Butiagrus Nabonnandii)
Cabbage Palm (Sabal Palmetto)
ZONE 9 PALMS (ADVANCED)
There are plenty of success stories of zone-pushing zone 9 palms. However, there are also countless failures as well. Chances of success are not nearly as high as zone 7 and 8 palms. More advanced techniques may be required ranging from using twin-wall polycarbonate to allow light in, to building moisture barriers and heating in the ground surrounding the roots.
Chinese Fan Palm (Livistona Chinensis)
Lady Palm (Rhapis Excelsa)
Pygmy Date Palm (Phoenix Roebelenii)
Bismarck Palm (Bismarckia Nobilis)
Mar 21, 2018
Human-caused global warming has the potential to transform coastlines, weather patterns, and entire populations. According to a new study published in Scientific Reports, the creep of palm trees into higher latitudes could be another sign that our planet is changing. If our climate continues to warm, the tropical flora could soon be spotted as far north as Canada.
In the new study, reported by Earther, researchers from Columbia University's Lamont-Doherty Earth Observatory and two Canadian institutions looked at the temperature tolerances of palm species best suited for chillier weather. Many varieties don't need a year-round tropical climate to thrive: As long as the average temperature for the coldest month of the year for the region is above 36°F, some palms can grow in northern latitudes. This is why you can see palm trees in Greenville, North Carolina, where average temperatures for January fall above 36°F, but not Washington D.C., where average January temperatures tend to dip below that number.
But that could soon change. As is the case with most northern states, average temperatures in D.C. are rising and winters are getting milder, which means it's shaping up to be an inviting habitat for palm trees. Not all palm species tolerate the same climatic conditions, and the effects of the species' competition with native and non-native plants in more northerly regions remains to be seen. But if the palms do migrate that far north in the coming years, the Northeast, Northwest, and even parts of Canada could be next.
A future of palm trees in Canada isn't as far-fetched as it may sound. Winters in these areas are already warm enough for people to plant palm trees in their gardens. In a controlled environment, these trees can flower and spread fruit, but average temperatures will need to climb a little higher before palm seedlings can survive in the wild.
[h/t Earther]