Chartreuse and violet is one of my all time favorite color combinations, and while it can be rather jolting if used in the wrong space, it seems to be rather comfortable in an outdoor setting.
Tip: Think about the colors of your existing plants and flowers when adding furniture if you're seeking a restful, consistent flow. If you want something more vivid but don't want it to come off too strongly, try using brighter hues from the same color family of your plants.