University of Washington Botanic Gardens

Selected cuttings from the Washington Park Arboretum (May 13 – 26, 2013)

1)   Aesculus x carnea ‘Fort McNair’

• A hybrid between A. pavia and A. hippocastanum, it probably originated as a chance hybrid made by insects in 19th-century Germany.
• Selected at the fort of the same name in Washington, D.C., flowers are pink with a yellow throat.
• It can be found on Azalea Way, across from the Woodland Garden.

2)   Buddleja globosa

• A species of flowering plant endemic to Chile and Argentina, where it grows in dry and moist forest.

Close-up view of the unusual orange flowers of the Buddleja globosa

• It can be found at both ends of the Arboretum at the Holmdahl Rockery and in the Graham Visitor Center parking lot.

3)   Embothrium coccineum   (Chilean Fire tree)

• A small evergreen tree from the temperate forests of Chile and Argentina.
• The plant was introduced to Europe by William Lobb during his plant collecting expedition to the Valdivian temperate rain forests in 1845–1848. It was described by Kew Gardens thusly: ”Perhaps no tree cultivated in the open air in the British Isles gives so striking and brilliant a display as this does.”
• There are several small specimens in the Chilean Gateway, and one large one just north of the bus turnaround on Arboretum Drive.

4)  Rhododendron x  ‘Favor Major’

• Hybridized by L. De Rothschild, the founder of Exbury Gardens in the United Kingdom.
• A beautiful orange Azalea, located on Arboretum Drive at the Rhododendron Glen parking lots.

5)  Syringa josikaea   (Hungarian Lilac)

• A species of lilac native to central and eastern Europe, in the Carpathian Mountains in Hungary, Romania, and western Ukraine.
• Located in the Syringa Collection on Azalea Way, just south of the Woodland Garden.

1)   Acer circinatum (Vine maple)

• Taken for granted around here, this time of year our vine maple is most eye-catching in flower.
• Located throughout our native matrix as a deciduous forest understory tree.
• Vine maple is native to the North American west coast from British Columbia to California.

2)   Acer cissifolium   (Vine-leaf maple)

• Despite their similar common names, vine maple and vine-leaf maple could hardly be more different. The Acer cissifolium leaf is compound, composed of three leaflets; Acer circinatum has almost round leaves. The flowers of Acer cissifolium have four petals (unusual for a maple) and are arranged in racemes while those of Acer circinatum are five-petaled and in panicles.
• Acer cissifolium is native to Japan. In the Arboretum, it is located in Rhododendron Glen (12-3E) and in the Asiatic Maples (27-B).

3)   Broussonetia kazinoki

• The inner bark is prized in Japan for making high-quality paper.
• A related species Broussonetia paperifera (paper mulberry) is used for paper from Myanmar to Japan and in Polynesia for the paper-like “tapa cloth”.
• The fruit begin to develop before the flowers produce pollen.
• Our Broussonetia is north of the Winter Garden in 35-3E and 36-2E.

4)   Rhododendron augustinii

• Provides the mauve backdrop for the beds along Azalea Way and in Rhododendron Glen.
• One of many plants discovered by and named for Augustine Henry in western China.

5)   Viburnum macrocephalum

• A China native introduced by Robert Fortune in 1844.
• Located in the Pacific Connections China Entry Garden.

“Now it will Spring forth!”

1)  Acer macrophyllum    (Bigleaf maple)

• Taken for granted around here, this time of year our Bigleaf maple is most eye-catching in flower.
• It’s the subtle texture of its expanding leaf that drew my attention.
• Located throughout our native matrix as the dominant deciduous forest tree.

2)  Aesculus wangii

• A horse chestnut classified as vulnerable in its native habitat of Vietnam.
• Notice the flattened bract-like stipule of the newly-expanding leaves.
• Our young, marginally-hardy specimen is located in Loderi Valley.

Close-up view of Kalopanax septemlobus (Prickly castor-oil tree)

3)  Kalopanax septemlobus    (Prickly castor-oil tree)

• Deciduous tree from northeast Asia known for its “tropical” appearance in full-leaf.
• I was impressed by the size of the bud bracts and pure white indumetum of the expanding leaves.
• This specimen is located along the eastern side of Arboretum Creek, south of Boyer Ave. East

4)  Picea meyeri    (Meyer’s spruce)

• Spruce tree native to China, similar in appearance to Colorado Blue spruce.
• Quite striking, springing forth new needles in combination with red male and female cones.
• Located in the Pinetum, just west of path and south of Stone Bridge.

Close-up view of the poplar, Populus sp

5)  Populus sp

• The detail and color contrast in the expanding leaf is awesome!
• This poplar is unidentified in our collections, but worthy of attention.
• Located in the Poplar Collection, south Azalea Way.

1) Azara dentata

• Native to temperate and subtropical Chile.
• Bears gold spring time flowers.
• Located in the Pacific Connections Chilean Entry Garden.

2) Liriodendron chinense

• A smaller Chinese version of the North American native tulip tree (Liriodendron tulipifera).
• Known for its unique leaf shape and tulip-shaped flower.
• Located in the Magnolia Collection.

3) Rehderodendron macrocarpum           

• A small deciduous tree native to China.
• Bears white spring flowers and kiwi-shaped fruits in the fall.
• Several specimens located along Arboretum Drive and Azalea Way.

4) Viburnum carlesii

• Native to Korea and Japan.
• Bears clusters of 2-3″ fragrant white flowers.
• Located in the Viburnum Collection.

5) Viburnum bitchiuense

• Native to Korea and Japan.
• Very similar to V. carlesii, possibly more heat tolerant.
• Located in the Viburnum Collection.

Pacific Connections Garden

1)  Corokia x virgata    ‘Sunsplash’

• An odd shrub from New Zealand with variegated foliage and wiry, twisty branches.
• This carefree evergreen tolerates some dry and looks great in containers.
• Specimens can be found in the New Zealand Entry Garden.

2)  Grevillea victoriae

• Fine-textured foliage, long thin flower clusters and drought tolerance make these evergreen shrubs very popular.
• Also known as Royal Grevillea, it is endemic to parts of Victoria in Australia.
• Several varieties of Grevillea can be found in the Australian Entry Garden.

3)  Gaultheria mucronata   ‘Rubra’ 

• A hardy evergreen shrub with pinkish-white bell-shaped flowers followed by beautiful red berries late summer through winter.
• Often referred to as “female prickly heath”, it needs a male plant to ensure fruiting.
• Beautiful masses of G. mucronata can be found in the Chilean Gateway Garden.

4)  Phyllostachys dulcis

• Sweet shoot bamboo is considered one of the best edible bamboos.
• Large drooping leaves, thick culms and a white ring at the node make this a very beautiful bamboo.
• A lovely drift graces the Chinese Entry Garden.

5)  Ribes sanguineum cv.

• Flowering current is native to western coastal North America.
• It and its varieties and cultivars are valued for their brightly-colored spring flowers and bird and habitat support.
• Enjoy the incredible display of Ribes currently blooming in the Cascadian Entry Garden.

1)  Camellia japonica  ‘High Hat’

• One of our earlier-flowering Japanese camellias.
• This specimen can be found along the west side of Arboretum Drive near the construction zone detour.

2)  Pieris japonica  ‘Valentine’s Day’

• Showing its large panicles of pink flowers.
• Can be found on Azalea Way just south of the Lilacs.

3)  Rhododendron floribundum

• Native to the Szechwan Province of China.
• Specimen currently resides along the Upper Trail near the Rhododendron seedling area.

4)  Salix irrorata

• Upright shrub with slender purple shoots and gray catkins borne before the leaves.
• Can be found in the Witt Winter Garden.

5)  Stachyurus himalaicus

• Native to western China and Taiwan.
• Spreading, deciduous shrub with arching shoots and bell-shaped flowers borne in racemes in late winter.
• Can be found on the west side of Arboretum Drive across from the double lot.

Witt Winter Garden

1) Chimonanthus praecox           Wintersweet

• Wintersweet is in the allspice family of Calycanthaceae.
• The sulfur-yellow flowers are intensely fragrant and are born on bare stems.
• This winter garden favorite is native to China.

2) Ganya x issaquahensis            Hybrid Silktassel

• This natural hybrid, between G. elliptica and G. fremontii, is native to the western U.S.
• The showy male catkins will soon produce large amounts of yellow pollen.

3) Hamamelis x intennedia ‘Pallida’           Hybrid Witch Hazel

• This cultivar produces large, pale-yellow flowers on a horizontal growing form.
• H. x intermedia is a hybrid between H. japonica and H. mollis, both native to Asia.

4) Hamamelis x intermedia ‘Winter Beauty’           Hybrid Witch Hazel

• This cultivar, though of the same parents as ‘Pallida’, has orange flowers on a taller,
  more rounded form.

5) Salix irrorata           Bluestem Willow

• The shoots of this upright shrub are purple with a distinct white bloom in the winter.
• The catkins are grey when they emerge, turning red and then quickly to yellow.

“Scratch and Sniff”

1)  Abies amabilis (Pacific Silver Fir)

• Pacific Northwestern native growing up to 250 feet tall in the wild, but is often short-lived in gardens.
• Its crushed needles smell like orange peel.
• The easiest of the Arboretum specimens to find is on the Upper Trail below the Peony bed.

2)  Cupressus goveniana var. pygmaea (Mendocino Cypress)

• The “pygmy” stature occurs in this tree’s native habitat: infertile ancient sand dunes above the Pacific Ocean near Mendocino. In normal soil, it can exceed 100 feet.
• The crushed needles smell like lemon peel.
• It is located on Arboretum Drive near the south end.

3)  Laureliopsis philippiana

• Native to Chile and Argentina.
• Crushed leaves smell like orange.
• It is located in the Pacific Connections Entry Garden and on Arboretum Drive in grid  9-4E.

4)  Morella pensylvanica (Bayberry)

• Formerly Myrica, native to the east coast of North America from Canada to Florida.
• The fragrant, waxy berries were made into candles.
• Located in 43-B in the Arboretum’s Oak Collection.

5)  Pseudotsuga menziesii (Douglas Fir)

• For Northwesterners, this is the essential smell of Christmas in the winter and the forest in summer.  It is native to the North American west coast and self-sows freely in the Arboretum.

“Judge a Plant by Its Cover”:  Twigs and Bark

Photo of Acer buergerianum (Trident Maple) trunk (#1)

1)   Acer buergerianum (Trident Maple) – photo of trunk (to the right)

• Move over Stewartia pseudocamellia, at least for the time being.
• Exceptional mottled flakey, lighter gray-brown bark on this young Asian maple.
• Makes a good street tree in Seattle, tolerant of a wide-range of stress factors.

2)   Acer caesium ssp. giraldii

• Maple featuring young branches covered with a whitish bloom (DO NOT TOUCH)
• Native to the Himalaya region of China (Shaanxi and Yunnan provinces)
• Specimen located along Arboretum Drive in the Peonies

Photo of Betula albo-sinensis var. septentrionalis (Chinese Red Birch) trunk (#3)

3)   Betula albo-sinensis var. septentrionalis (Chinese Red Birch) – photo of trunk (to the right)

• “The bark is singularly lovely, being a rich orange-red or orange-brown and peels off in sheets, each no thicker than fine tissue paper, and each successive layer is clothed with a white glaucous bloom.”  – E.H. Wilson, Aristocrats of the Trees
• Please resist the temptation to tear, pull, rub… the bark.  It is disrespectful, potentially harmful to the tree, and a crime to deface public property.
• Grove located in the Witt Winter Garden.

Samples of #2, #4, and #5

4)   Cornus sanguinea   ‘Midwinter Fire’

• A multi-colored thicket-forming dogwood.
• Brightens up ones’ spirits on any dark and gloomy winter Seattle day.
• Located in the twig bed of the Witt Winter Garden.

5)   Prunus maackii   (Manchurian or Goldbark Cherry)

• Not as common as the Birchbark Cherry, but has brighter honey-brown bark.
• Located on the north toe of Yew hill, grid 30-3W.

Seize the Bay!

1)   Bay Laurel    (Laurus nobilis)

• From the Mediterranean region
• A plant of great cultural significance (culinary uses, literary references, etc.)
• Marginally hardy in the Washington Park Arboretum, located in the Mediterranean Bed (grid 21-3E)

2)   California Bay Laurel    (Umbellularia californica)

• Native to the Pacific Coast, Oregon through California
• Crushed leaves have intense odor
• Re-seeds freely in the Washington Park Arboretum
• Located near the Mediterranean Bed (grid 20-3E)

3)   Redbay    (Persea borbonia)

• A relative of the avocado, native to southeastern U.S.
• Used as an emetic (vomit inducer) by indigenous people
• Located in the the Camellia Collection near the Reebs memorial bench (grid 11-4E)

4)   Rosebay    (Rhododendron maximum)

• Native to eastern U.S.
• Used in the early days of Rhododendron hybridizing to develop hardy hybrids
• Growing steadily in the Rhododendron Seedling Bed (grid 22-1E)

5)   Sweet Bay    (Magnolia virginiana)

• Eastern U.S. native
• Typically evergreen in Seattle, but can be deciduous, semi-deciduous, or evergreen depending on climate
• Located in the Magnolia Collection (grid 28-3E)