Advancing the Conservation, Study, and Cultivation of the Flora of Asia

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Join us for Quarryhill's 2nd Annual Wild Collections, Expeditions for Education Fundraiser on Saturday, May 17th 5:30-8:00 PM



Quarryhill became the first ACS Reference Garden in California in 2013.


Spotlight Plant 

Magnolia kobus

(QBG #1989.205)


Collected by Mike Maunder, Bill McNamara and Shigeto Tsukie as collection number SOJA-205 on October 22, 1989 at 910 meters elevation from cultivated trees of original wild origin, growing in the Ritsurin Park, Taka-matsu City, Mount Ohtaki, Kagawa Prefecture, Shikoku Island, Japan (N 34 deg. 06', E 134 deg. 08').

Magnolia kobus is a deciduous tree in the Buergeria section of the Magnolia family, native to all principal islands of Japan, except for Shikoku, and to Chuju-Do (island) of South Korea.  It can grow to 30 m in height, with stout, glabrous branches.  Leaves are puckered, of a papery or leathery texture and obovate in shape, 6-13 cm long by 3-6 cm wide with a cuneate base and abruptly acuminate tip.  Flowers appear March - May, are precocious (appear before leaves), funnelform to lily-shaped, 7-12 cm across, erect to horizontal, often subtended by 2 small leaves, and white sometimes with rose-purple or pale green centers.  Three linear sepals are pink-ish at base and 6-8 petals are narrowly obovate, 3.5-6 cm long by 1-1.8 cm wide, spreading and usually reddish to pale greenish near base.  Stamens are creamy white, sometimes tinged light purple.  Carpels are green, and both styles and stigmas are creamy white.  The fruit is short and cylindrical, 7-10 cm long.



Founded in 1987, Quarryhill is one of the pre-eminent Asian botanical gardens globally, featuring one of the largest collections of documented, wild-collected Asian plants in the world. It is centrally located for Sonoma, Marin and Napa counties as well as greater Northern California. 

Quarryhill's core programs include:

The garden welcomes visitors and is open year-round.

Currently of Interest in the Garden
Plant Name
Common Name

Weigela hortensis



Rhododendron japonicum



Rosa odorata var. gigantea


Rosa laevigata


Kolkwitzia amabilis


IMG_1975.JPG  Rosa rugosa