The Beekman Native Plant Arboretum 3 acres (12,000 m²) features trees, shrubs and herbs from eight zones of the Siskiyou and Cascade mountains in southern Oregon. It is located behind the Beekman Museum House, at 352 East California Street, Jacksonville, Oregon, USA.

The Arboretum contains more than 175 species from the high deserts of Eastern Oregon, high-altitude subalpine slopes around Crater Lake, and serpentine soils of the Siskiyou Mountains. It features species from the chaparral, low-elevation forest and riparian zones, including grassland plants, lodgepole pine and sagebrush, buckwheat, penstemon and balsam root, and a bog with skunk cabbage and wild ginger. Most plants are labeled with name and habitat. Two footbridges cross a seasonal stream.

The arboretum was designed by Alan Horobin, in collaboration with the Jacksonville Woodlands Association, organized in 1989 to preserve the woodlands behind the 1875 Cornelius C. Beekman house.