This is the most northern garden I have ever visited.
Fortunately, because of the moderating effect of the ocean,
it is very similar to the growing conditions in Portland or
Seattle. The garden has a wide array of temperate zone
plants and one of the features is the tree root planters.
Someone got the idea of turning a tree upside down and using
the root area as a place for holding potting soil and
trailing plants. Pretty neat.