Beginning in the nineteenth century, color plays an important role in the development of garden design. Gardens began to incorporate contrasting and complementary hues, thus instilling new artistic principles which gave rise to the beginning of color theory in the landscape. Its significance can be best appreciated while understanding the painting movements which influenced the gardens of four case studies. The history of color theory will be addressed in the thesis, as well as the garden designs of Gertrude Jekyll, Roberto Burle Marx, and the partnership of Wolfgang Oehme and James van Sweden. The thesis concludes with an analysis of five criteria which show the similarities and differences between the usage of color found in the four case studies designs.