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In Bloom

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.

Location 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.net: comprehensive site for Vireya Rhododendrons with more than 900 images. Our local chapter of the American Rhododendron Society Profile Contributor: Fred Bové

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.

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Magnolia campbellii January	Magnolia denudata February	Magnolia x veitchii March
Iris douglasiana April	Aesculus californica May	Vaccinium ovatum June

Acer palmatum 'Sango kaku' January	Magnolia campbellii 'Darjeeling' February	Bomarea spp. March
Rhododendron occidentale April	Polystichum munitum May	x Chiranthofremontia lenzii June
Salvia leucantha July	Hydrangea seemannii August	Wollemia nobilis September
Cyathea cooperi October	Pinus radiata November	Correa spp. December

Garrya elliptica January	Magnolia x soulangeana February	Senecio glastifolius March
Ribes spp. April	Oxalis oregana May	Calandrinia grandiflora June
Taxus baccata July	Romneya coulteri August	Passiflora parritae September
Malvaviscus arboreus October	Monterey Cypress November	Aloe arborescens December

Aloe plicatilis January	Banksia seminuda February	Zantedeschia aethiopica March
Magnolia laevifolia April	Araucaria heterophylla May	Toxicodendron diversilobum June
Clarkia sp. July	Agapanthus August	Brugmansia September
Cedrus spp. October	Protea repens November	Camellia sinensis December

Thujopsis dolabrata January	Gordonia longicarpa February	Rojasianthe superba March
Echium spp. April	Iris douglasiana May	Digitalis purpurea June
Felicia amelloides July	Ceroxylon quindiuense August	Amaryllis belladonna September
Ginkgo biloba October	Acer morrisonense November	Ilex aquifolium December

Picea sitchensis January	Telanthophora grandifolia February	Aeonium arboreum 'Schwartzkopf' March
Leptospermum April	Salvia gesneraeflora May	Lavandula spp. June
Pelargonium July	Fuchsia paniculata August	Luma apiculata September
Luculia October	Arbutus unedo November	Cycad December

Restionaceae January	Hellebores February	Ceanothus March
Rhododendron April	Psoralea pinnata May	Fremontodendron californicum June
Leucadendron argenteum July	Crocosmia August	Gunnera tinctoria September
Pellaea rotundifolia October	Fuchsia boliviana November	Erica canaliculata December

Magnolia campbelli January	Magnolia denudata February	Camellia March
Geranium maderense April	Acmena smithii May	Eschscholzia californica June
Dendromecon harfordii July	Romneya coulteri August	Eupatorium purpureum September
Epilobium canum sp. October	Grevillea spp. November	Drimys winteri December