San Francisco Botanical Garden - Gardens

Rhododendrons can be found in the Rhododendron Garden (beds 72A-D, 73A-F, 28); Vireya Rhododendrons are located in the Southeast Asia Cloud Forest (Beds 78E-I); Additional specimens are in bed 49A-I.

Scientific Name	Rhododendron spp.
Common Name	Rhododendron, Rose Tree, Rosebay
Family	Ericaceae
Plant Type	Evergreen or deciduous shrubs (sometimes trees or epiphytes)
Environment	Filtered shade, moist conditions, does well in our foggy climate, thrives in well amended acid soil, does not like alkaline conditions or heavy clay. Because of the shallow root system, does best without competition from aggressive ground covers or surface rooting trees.
Bloom	Rounded clusters "trusses" of tubular flowers with a wide color range from white, pink, yellow and salmon through dark reds and purples, depending on the variety.
Uses	Superb plant for beauty in moist, shady or foggy sites. Caution: the mature leaves are poisonous, flowers and their honey can be toxic.
More Info	Vireya Rhododendrons in SFBG's Southeast Asian Cloud Forest Vireya.net: comprehensive site for Vireya Rhododendrons with more than 900 images. Fragrant rhododenrons! Our local chapter of the American Rhododendron Society

Profile Contributor: Fred Bové

Rhododendron
'Rose Tree,' 'Rosebay'

China was called the "mother of gardens" by English plant explorers of the 19th century and contains three-fourths of the species of rhododendrons found in the world. The majority are located in Yunnan Province in southwestern China, and are most abundant between altitudes of 8,000 to 11,500 feet. The large, spectacular blooms range in colors of red, pink, white, and even yellow (R. macabeanum.) Some are a few inches high and hug the ground, others are 100 foot giants.

R. arboreum (tree-like) was introduced in 1811 to England. After it was hybridized with hardy R. catawbiense from the southern Appalachians, an "ironclad" group of hybrids was developed, able to survive English winters. Another species hybrid is R. 'Fragrantissimum' (a cross between R. edgeworthii and R. formosum) and has intense perfume.

R. maddenii clings as an epiphyte to the limbs of trees in the Himalayan forests. Here, in our mild climate with its foggy days, it grows as a shrub, and its fragrance and delicate white to pink blooms have made it a favorite for hybridization. Our botanical garden has the finest collection of Maddenii rhododendrons in North America.

Rhododendrons are mostly evergreen shrubs with a variety of leaf sizes and flower shapes. All require rich soil, light shade and moisture. Besides Asia and the islands of the Pacific, they are also found in Europe, Canada, Alaska, along our West Coast, and in the Middle Atlantic States.

Available at our next plant sale