Portland's Rose Society was founded in 1889, and the city's collection of hybrids, floribundas, and grandifloras has been growing ever since. In 1917 the International Rose Test Garden opened as a testing ground for new varieties of roses. Some of its first plantings were rose refugees from Europe during World War I. Today, over 10,000 plants and 550 species slope towards the city's downtown horizon.
In the early 1900s, Portland was already known as "The City of Roses," thanks to 20 miles of rose-bordered streets (planted for the 1905 Lewis & Clark Exposition) and lots of local rose lovers. The Portland Rose Society was founded in 1889.