Scientific name: Prunus species
Various species:
P. Sato-zakura Group: Cultivars: ‘Shirotae’, ‘Shoetsu’, ‘Ukon’ ‘Chosho-Hizakura’, Sekiyama’
‘Ohochin’ ‘Oeshokun’
P. serrulata: Cultivars: ‘Asagi’ ‘Iohiyo’, ‘Shirofugen’, ‘Tai-Haku’, ‘Taoyome’ ‘Wase-Miyako’ ‘Horinji’
P. subhirtella: Cultivars: ‘Eureka Weeping’ ‘Pendula’ ‘Rosea’ ‘Stellata’ ‘Higan Weeping’ ‘Whitcomb’
P. sargentii: Cultivar: ‘Pink Flair’
Prunus x yedoensis: Cultivar: ‘Akebono’, ‘Shidare-yoshino’, ‘Somei-Yoshino’
P. x juddii
Common name: Japanese Ornamental Cherry
Family: Rosaceae
Native Range: Japan
In the Arboretum: Along Azalea Way
Issues: brown rot, cherry bark tortrix larvae, crown gall, root rot, low tolerance of compacted or wet soils

During spring’s first blossoms, I brag to anyone who will listen that the Japanese ornamental cherries at the Washington Park Arboretum are the most amazing display in the city and that they MUST go for a walk along Azalea Way to view this splendor. 

Scientific name: Trochodendron aralioides
Synonyms: Trochodendron longifolium
Common name: Wheel tree, parasol tree, birdlime tree, yamaguruma, nagaba-no-yamguruma, kun lan shu, ka-tang-lai
Family: Trochodendraceae
Native Range: Japan (south of Yamagata), Kyushu, Shikoku, Ryuku Islands, Taiwan
Height and Spread: May grow from 60-75 tall feet in the wild with trunks as large as 16 feet in diameter, typically 20-25 feet tall by 10-15 feet wide in cultivation. 

Scientific name: Ailanthus altissima
Common name: Tree of Heaven, Stinking Sumac, Paradise Tree
Family: Simaroubaceae
Native Range: Taiwan and China, hardy to USDA Zone 4
Habit: Grows between 60-90 feet tall and can grow to around 25 feet in a single year. The bark is smooth and tan to gray in early growth. With age, bark will become rugged with heart-shaped leaf scars. 

Scientific name: Cornus mas 
Common name: Cornelian cherry, European cornel, Cornelian cherry dogwood
Family: Cornaceae (Dogwoods)
Native range: Southern and central Europe to western Asia
Location: At the Center for Urban Horticulture, there is a grove located in the northern lawn area along the central drive and the trees’ accession numbers are 87-90. At the Arboretum, there are three specimens under the accession number of 704-38 (grid 33-B) from the original planting of the Woodland Garden in 1938. 

Hardy Fuchsia love sun and do fine in part shade.  Once established they tend to be drought hardy plants – I have one in my yard that I never water in summer and it has thrived over the past 15 years.  They are the hardiest species of the Fuchsia genus and are rated for USDA Zones 6 & 7.

In Japan, the seeds of the nutmeg yew are desirable to be roasted and eaten or used to produce a cooking oil with a subtle nutty flavor highly prized in some circles for tempura. The ‘nuts’ are rich in vitamin E as well as sciadonic acid, known to reduce cholesterol.

As Spring arrives, we here in the Pacific Northwest are gifted the opportunity to observe a wide variety of plant species we may not have noticed before. This month, we are focusing in on a beautiful, rare, San Francisco Bay-area endemic shrub. Dirca occidentalis can be found in the Washington Park Arboretum, but wait… what is it doing here?

The Baker cypress, the most northern and hardiest cypress in North America is a tree with a challenging future ahead of it. Within its native range of southern Oregon and northern California there are several populations, many a long distance separate from others.

What better time than winter to highlight one of the Arboretum’s conifer specimens? January is also an excellent time to take a trip out to Foster Island to walk amongst some of the many birds that make the Arboretum home. Beside the path on Foster Island – just before you cross under the 520 bridge – you will find a pair of Pinus rigida. The species name rigida refers to its stiff and sharp cone scales and needles. The tree’s common name – pitch pine – derives from the high resin content in its wood.

We added an interesting specimen this year as a foundation tree in the newly renovated Soest Herbaceous Display Garden bed 3. Our Bronze Loquat was grown from seed that was wild collected by Dan Hinckley at higher elevation in the mountains of Taiwan. We received a sapling from Dan in 2014 and have grown it to larger size in our nursery before planting earlier this year.