Why are hockey rinks called gardens?

The word "garden" also used to mean a large area for public events. For many of these arenas, it's a holdover from when they were built, as the meaning of the word was still popular at that time. For others, it's an homage to a previous building built back when that meaning of garden was still popular. For still others, it's used just because it sounds nice, even if nobody really uses "garden" for that meaning anymore.