The Devonian Botanical Gardens are located in Edmonton, Canada. They were started in 1959, and contain over 190 acres of manicured gardens, woodlands, and hiking trails.
There are eleven featured gardens, including a butterfly house, a cactus house, an ornamental flower garden, a native Indian garden, an alpine garden, and my personal favorite, the Kurimoto Japanese Garden. The Japanese garden is five acres of ponds, waterfalls, grassy hills, and numerous Japanese sculptures.
The gardens are open every day except Thursday, from 10 AM -6 PM. Admission is free, unless you want a private guided tour. Admission for that is 13 Canadian dollars.