The wreath has been a symbol for thousands of years. In ancient Greece and Rome, wreaths symbolized victory so were worn like a crown by soldiers returning from a war, Olympic athletes, and other contest winners. In Rome, wreaths of flowers were often worn by women during festivals and weddings and generally symbolized pride.
Wreaths today are often made of holly, pine, or other evergreen plants or tree branches. Evergreens are a symbol of eternity or life everlasting. Wreaths are usually circles. Circles symbolize something never ending, eternal. So when you combine evergreens with the circular shape you get what early Christians considered a symbol of the victory of spirit over matter or the soul over the logical mind.
Today, wreaths are made for many occasions and primarily to decorate the home, usually, with no knowledge or interest in the symbolism of the wreath. Nonetheless, the soul remembers and having spiritual symbols around helps to remind it of it’s origin in the eternal worlds of spirit.