Famous Rose Test Garden Oregon References. The international rose test garden and its preservation of a great variety of roses began with the onset of world war one. The site is popular around the globe and is the oldest, continuously operated public rose test garden in the united states.

Web the international rose test garden was founded in 1917 and is the oldest continuously operated public rose test garden in the united states. Washington park brings in 3.5 million visitors annually. The oldest official continuously operated public rose test garden in the united states, the portland international rose test garden in washington park features more than 10,000 roses, great.