Abstract: A corner brace for use in constructing a planter or enclosure is provided. In the preferred embodiment of the invention the corner brace comprises a first vertical plate, second vertical plate, transverse connecting bottom plate, and a bracket-forming internal support structure. In use, each corner brace supports and restricts the ends of at least two sidewalls of a planter or enclosure. A first sidewall is supported between the first vertical plate and one side of the internal support structure. A second sidewall is supported between the second vertical plate and a second side of said internal support structure. Preferably, the sidewalls comprise a resilient yet slightly flexible material such as wood, recycled plastic lumber or other similar materials.