Interesting thread, I recall the numerous palms in Vancouver when I was there on several visits in years past. As far as natural environment, they felt entirely natural in the Vancouver area. I lived on the west coast during summer 07 to spring 08 and I clearly remember that region having a Mediterranean climate during the entire middle part of the year and is extremely dry, while out east you get lots of storms in the summer months. In Ontario I think it does feel a bit 'unnatural' by comparison, but I'm not opposed to trying to grow some if we can!
BTW, a lot of the Great Lakes beaches in the area have tropical-like grasses and the summers are warm enough here to give a nice feeling in the outdoors. Vancouver, from what I gather, is generally chillier during the summer months than southern Ontario because of it's relation to the cool north Pacific waters. But it is much milder during winter as we all know...
The summers aren't that cool here, I took a snapshot of this weather forecast back in July in the Buffalo and Niagara areas as an example of what it was like this year.
You rarely get that long of a period of consistently burning hot weather in Vancouver, no? 91F is 32C, and the humidex would generally be over 40 each day.