June Color Appears at the Washington Park Arboretum (Part II)

July 2nd, 2015 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (June 22 - July 5, 2015)

Selected cuttings from the Washington Park Arboretum (June 22 – July 5, 2015)

1)  Quercus gilva                    Evergreen Oak

  • Native to China and Japan
  • Reaches heights of 90-100 feet in its native range
  • Located in the Oak Collection along the South Oaks Extension Trail

2)  Rhododendron calophytum           Beautiful-face Rhododendron

  • Native to China
  • Large species rhododendron capable of becoming a tree
  • Located along trail between Loderi Valley and the Woodland Garden

3)  Sequoia sempervirons  ‘Cantab’                     Coast Redwood

  • A cultivar of the coast redwood with unique needles
  • Specimens vary in form from shrubby to tree-like
  • Located in the north end of the Pinetum, along the Pinetum Trail

4)  Thujopsis dolobrata                    Hiba Arborvitae

  • A Japanese native
  • Capable of reaching 100 feet or more in Japan, yet large specimens are rare in the Seattle area
  • Located along the south slope of the Woodland Garden

5)  Viburnum rhytidophyllum                    Leatherleaf Viburnum

  • Native to China
  • Large evergreen shrub recorded to heights of 30 feet
  • Located along the trail through the Viburnum Collection

March Color Appears at the Washington Park Arboretum

March 9th, 2014 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (March 3 - 16, 2014)

Selected cuttings from the Washington Park Arboretum (March 3 – 16, 2014)

1)   Berberis fortunei      (Chinese Mahonia)

  • Previously categorized in the genus, Mahonia
  • Characterized by narrow, serrated evergreen leaves
  • Located in the Sino-Himalayan hillside

2)   Grevillea victoriae      (Mountain Grevillea)

  • Australian shrub, growing up to four meters
  • Named for Queen Victoria
  • Located in the Pacific Connections – Australia Entry Garden

3)   Lomatia myricoides      (River Lomatia)

  • Originally placed in the genus, Embothrium
  • Specific epithet refers to foliage similar to the genus, Myrica
  • Located near the Pacific Connections – New Zealand Forest

4)   Morella californica      (California Bayberry)

  • Formerly of the genus, Myrica
  • A Pacific Coast native shrub that is well suited for borders and hedges
  • Located in the Pacific Connections – Cascadia Entry Garden

5)   Podocarpus macrophyllus      (Kusamaki)

  • Japanese conifer, sometimes referred to as Buddhist Pine
  • Known by carpenters for termite resistant wood
  • Located near the junction of the Middle Trail and Lower Trail

February Color Appears at the Washington Park Arboretum (Part II)

February 23rd, 2014 by Pat Chinn-Sloan


“Spring Buds”


Selected cuttings from the Washington Park Arboretum (February 17 - March 2, 2014)

Selected cuttings from the Washington Park Arboretum             (February 17 – March 2, 2014)


1)   Acer monspessulanum var. turcomanicum
Montpelier maple

  • An elegant, compact tree reaching 23-33 feet tall.
  • Suitable for warm climates and adapted to calcareous and stony soils.
  • A mature individual is growing in the Mediterranean bed along Arboretum Drive.

2)   Magnolia kobus                Kobushi Magnolia

  • Blooms in early spring and bears pleasantly fragrant white flowers.
  • Native to Japan and cultivated in temperate climates.
  • A lovely, large specimen sits in the Arboretum Magnolia Collection.

3)   Rhodondendron ‘Directeur Moerlands’
Azalea ‘Directeur Moerlands’

  • Derived from crosses between Japanese azaleas and Chinese azaleas.
  • Known for their excellent fall color and unsurpassed springs flowers.
  • Azalea Way is loaded with beautiful azaleas just ready to explode for spring.

4)   Ribes sanguineum ‘Henry Henneman’           Henry Henneman Winter Currant

  • Studded with a cap-burst of color at a botanically bereft time of year.
  • Easy to grow, well-mannered and amenable to pruning.
  • The Cascadian Entry Garden boast several cultivars of this wonderful, early blooming shrub.

5)   Sambucus racemosa              Red Elderberry

  • Grows in riparian environments, woodlands and in generally moist areas.
  • Many parts of the plant are poisonous and have been used as an emetic.
  • Native to the Pacific Northwest, elderberry bushes dot the Arboretum. Birds love the seeds.

February Color Appears at the Washington Park Arboretum

February 6th, 2014 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (February 3 - 16, 2014)

Selected cuttings from the Washington Park Arboretum             (February 3 – 16, 2014)

1) Chimonanthus praecox  Wintersweet

  • With exceedingly fragrant yellow flowers borne on the bare shoots in winter, C. praecox has a suitable home here within the Witt Winter Garden.
  • Chimonanthus is the Chinese counterpart of the North American genus, Calycanthus.

2)  Lonicera standishii Winter Honeysuckle

  • A native of China, L. standishii is a perennial favorite because of its charming fragrance.
  • This specimen can be found in the Witt Winter Garden.

3)  Pieris japonica ‘Valentine’s Day’

  • Known commonly as ‘Lily of the Valley’, P. japonica is an evergreen shrub of low habit. The clustered panicles of this particular cultivar are a dark, dusky red color, giving it plenty of mid-winter attraction.
  • Located near the south end of the Lilac Collection along Azalea Way.

4)  Prunus x subhirtella ‘Rosea’

  • Native to Japan, this relatively small flowering cherry has begun to show us its rose-pink blossoms.
  • Several specimens can be found throughout the Arboretum, including one along the trail that leads from here to the Winter Garden.

5)  Viburnum specimens

  • V. farreri ‘Candidissimum’
  • V. foetens
  • V. x bodnantense ‘Deben’

January Color Appears at the Washington Park Arboretum

January 13th, 2014 by Pat Chinn-Sloan
Selected cuttings from the Witt Winter Garden at the Washington Park Arboretum (January 6 - 19, 2014)

Selected cuttings from the Witt Winter Garden at the Washington Park Arboretum (January 6 – 19, 2014)

Witt Winter Garden

1)  Calluna vulgaris ‘Robert Chapman’            Heather, Ling

  • This monotypic genus is native from northwestern Europe, through Siberia and Turkey, all the way to Morocco and the Azores.
  • The species has over 500 cultivars – some noted for spectacular flower displays in summer, while others display fantastic foliage coloration in winter.
  • C.v. ‘Robert Chapman’ has golden foliage throughout summer, which turns red in winter and spring.

2)  Cornus sanguinea ‘Midwinter Fire’           Bloodtwig Dogwood

  • In winter, the yellow stems of this twiggy shrub brighten to a stunning display of reds and oranges, depending on sun exposure.

3)  Danae racemosa           Alexandrian, Poet’s Laurel

  • This native of Iran and Turkey has no true leaves, only leaf-like modified stem tissue called phylloclades.
  • Tiny, yellow flowers that grow directly on the stem produce dramatic red fruits in winter.
  • Poet’s Laurel was used by the Romans and Greeks to crown exemplary athletes, orators and poets.

4)  Garrya x issaquahensis ‘Carl English’           Silk Tassel

  • A hybrid of G. elliptica and G. fremontii, this Garrya bears purple-tinged silvery flower tassels in winter.
  • Both parents are native to the west coast of the United States.

5)  Hamamelis mollis           Witch Hazel

  • This Chinese witch hazel has large, very fragrant, golden-yellow flowers in early winter.

December Color Appears at the Washington Park Arboretum (Part II)

December 16th, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (December 9 - 23, 2013)

Selected cuttings from the Washington Park Arboretum (December 9 – 23, 2013)

1)   Abies balsamea   (Balsam fir)

  • Pitch from almost every conifer is used to seal and protect wood.
  • “Canada Balsam” from the Balsam Fir is used to cement together the lens elements in optical equipment and to mount specimens for microscopy.
  • It is North America’s most popular Christmas tree, but only newly planted in the Arboretum in grid 42-4W.
  • Native to eastern North America

2)   Cedrus libani   (Cedar of Lebanon)

  • “Cedar oil” is distilled from several conifers, mostly not Cedrus, the “true cedar”.
  • Cedar oil has insecticidal properties, was used in ancient embalming, and is currently used as immersion oil in microscopy and to mask surface flaws in emeralds.
  • Several of our true cedars – Cedar of Lebanon, Atlas Cedar, and Deodar Cedar are located along the Lynn Street entrance, west of the Wilcox foot bridge.

3)   Picea sitchensis   (Sitka spruce)

  • Before the introduction of chicle, North Americans (both natives and immigrants) chewed spruce gum.
  • Spruce roots are used for stitching bark canoes and weaving hats and baskets.
  • The famous “Spruce Goose” was not spruce but acquired its alliterative sobriquet because early airplane builders valued spruce’s high strength-to-weight ratio.
  • Our best Sitka spruce is in 15-B on Azalea Way.

4)   Pinus monticola   (Western white pine)

  • The Lower Kootenay Band of the Ktunaxa Nation made bark canoes from white pine bark.   See the website: sturgeon-nose-creations.com
  • Industrially, pine extracts make pine tar, turpentine, pitch, and rosin for violin bows, ballet shoes, baseball bats, and soldering flux.
  • Pinus monticola is in the Pinetum in grid 35-6W.

5)   Quercus suber   (Cork oak)

  • Quercus = oak, suber = cork. Location: Rock Roses on Arboretum Drive.
  • Any questions?

December Color Appears at the Washington Park Arboretum

December 1st, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (November 26, 2013 - December 9, 2013)

Selected cuttings from the Washington Park Arboretum (November 26, 2013 – December 9, 2013)

“Berry Best from Hollywood”

1)   Ilex aquifolium   ‘Ferox Argentea’   (Variegated Porcupine Holly)

  • This “Punk” star is a sterile male with spiny leaves, but obviously no berries.
  • But this means it doesn’t contribute to English holly’s invasiveness in the Pacific Northwest.
  • Old cultivar in England, first reported in 1662 (Galle).
  • Specimen is located in the Eurasian clade (family), W. berm, of the Ilex Collection.

2)   Ilex maximowicziana var. kanehirae

  • This “Mod” diva has a tidy upright form with black berries.
  • Native to China and Japan
  • Has gone through many name changes, intermediate between I. crenata and I. triflora.
  • Specimen is located in the Asian/North American clade of the Ilex Collection.

3)   Ilex opaca  ‘Boyce Thompson Xanthocarpa’

  • An American holly celebrity which dares to be different, sporting yellow berries.
  • Reported to have been discovered in the wild, Mount Vernon, VA, late 1920’s.
  • Specimen located in the American clade, S. berm, of the Ilex Collection.

4)   Ilex verticillata  ‘Winter Red’     (Winterberry cultivar)

  • You don‘t always need to be dressed in leaves, says this scarlet actress.
  • Reliable shrub with heavy, bright red fruit set and good berry retention.
  • A nice thicket is found along Azalea Way, just north of Lookout Pond.

5)   Ilex x  ‘Nellie R. Stevens’

  • This mischievous leading lady has been nothing but trouble!
  • Claiming English holly parentage, but also Chinese holly parentage. In any case, no denying she certainly resembles English holly in my book.
  • Specimen is located in the Eurasian clade, N. berm, in the Ilex Collection.

November Color Appears at the Washington Park Arboretum (Part II)

November 18th, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (November 12 - 25, 2013)

Selected cuttings from the Washington Park Arboretum (November 12 – 25, 2013)

Got Greens?

1)   Fokienia hodginsii     (Fokienia)

  • Native to China, Vietnam, and Laos
  • Extremely slow growing outside of native range
  • Specimen located in Rhododendron Glen

2)   Keteleeria evelyniana     (Keteleeria)

  • Native to China, Vietnam, and Laos
  • Thrives in warm climates, but may be considered an “herbaceous perennial” in northern climates
  • Specimen located in north Pinetum area

3)   Taiwania cryptomerioides     (Coffin Tree)

  • Native to Taiwan, China, and Vietnam
  • Considered “critically threatened” in native range
  • Specimen located near East Newton Street entrance to the Pinetum area

4)   Thujopsis dolabrata     (Lizard Tree)

  • Native to Japan
  • Thrives in moist, shady areas with rich soil
  • Specimen located among Acer Collection in the Woodland Garden

5)   Torreya taxifolia     (Stinking Cedar)

  • Native to southeastern U.S. (Florida)
  • Very rare in native range due to a fungal pathogen
  • Specimen located between Loderi Valley and the Woodland Garden

November Color Appears at the Washington Park Arboretum

November 3rd, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (October 28, 2013 - November 11, 2013)

Selected cuttings from the Washington Park Arboretum (October 28, 2013 – November 11, 2013)

1)  Arbutus unedo   (Strawberry Tree)

  • One of the many species described by Carl Linnaeus in his 1753 landmark work, Species Plantarum.
  • An amazing plant with 4-season interest, including fruits and flowers at the same time.
  • Serves as a bee plant for honey production and the fruits are food for birds.

2)  Camellia wabisuki   (Wabisuki Camellia)

  • A Sukiya variety with single, pinkish-white flowers and an open growth habit.
  • A 70-year-old specimen heralds the magnificent seasonal display in the Witt Winter Garden.
  • The flowers of Wabisuki are often used in decorations for Japanese tea ceremonies.

3)  Drimys winterii   (Winter’s Bark or Canelo)

  • A slender tree growing to 60’ feet and native to the temperate rain forests of Chile.
  • For centuries, Winter’s Bark was esteemed as a preventative remedy for scurvy before vitamin C was isolated.
  • Grown as an ornamental plant for its reddish-brown bark, and clusters of creamy white jasmine-scented flowers.

4)  Franklinia alatamaha   (Franklin Tree)

  • The sole species in this genus, commonly called the Franklin Tree.
  • Commercially available for garden cultivation and prized for its fragrant white flowers
  • Botanist, William Bartram named this elegant tree in honor of his father’s friend, Benjamin Franklin.

5)  Rhododendron occidentale   (Western Azalea)

  • There is considerable diversity in form and appearance of this species.
  • Tolerant of serpentine soils, it is part of the unique plant community found in the Siskiyou Mountains.
  • The Western Azalea was an early contributor in the development of hybrid azaleas.

October Color Appears at the Washington Park Arboretum

October 7th, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (September 30 - October 13, 2013)

Selected cuttings from the Washington Park Arboretum (September 30 – October 13, 2013)

The Good, The Bad and The Ugly (Minus the Good)

1)  Cherry Brown Rot

  • A fungal disease of the Prunus species caused by Monilina fructicola and Monilina laxa.
  • The first symptoms often seen are browning and collapse of the blossoms, followed closely by death of the small twigs.

2)  Dogwood Anthracnose

  • Dogwood anthracnose is a disease of flowering and pacific dogwoods (Cornus florida and C. nuttallii).
  • An anthracnose fungus, Discula sp., has been identified as the causal agent.
  • Infection of dogwoods is favored by cool, wet spring and fall weather, but can occur throughout the growing season.

3)  Elm Leaf Miner

  • Elm leaf miner, Fenusa ulmi, is a pest that feeds on the tissues in between the outer layers of elm leaves, causing browning and leaf drop. Although primarily an aesthetic pest, leaf miner damage can stunt or weaken a tree when the population in the tree is high.
  • The elm leaf miner has been in the Northwest for a few years, but recent expansion has been noticeable in Washington and Oregon recently.

4)  Powdery Mildew on Rhododendron

  • The fungus Microsphaera azalae is found throughout the Pacific Northwest on Rhododendron species and hybrids.
  • Contrary to popular opinion, powdery mildew outbreaks are not favored by rainy weather. Steady rain tends to wash mildew spores off the foliage before they have a chance to penetrate the tissue. Mildew is more commonly associated with high relative humidity and the light coating of dew that forms on leaves when cool nights follow warm days.

5)  Sorbus Sawfly

  • The Sorbus Sawfly (Pristiphora geniculate) is a new pest in western Washington. It was first noticed in the spring of 2009 in the Everett, Lynnwood and Monroe areas.
  • Sawflies that are new to an area tend to build up in large numbers and can cause significant defoliation. Sawfly larvae typically eat continuously and then drop out of sight (to pupate in the soil). Damage appears to occur overnight. Control of the first generation will reduce the number and severity of defoliation by the second and third generations.