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.

September Color Appears at the Washington Park Arboretum

September 23rd, 2013 by Pat Chinn-Sloan

Keystone Species of New Zealand

Keystone species of New Zealand (September 9 - 22, 2013)

               Keystone Species of New Zealand                     (September 9 – 22, 2013)

1)   Nothofagus menziesii   (Silver Beech, Tāwhai)

  • Natural range: endemic to New Zealand.  Found throughout South Island.
  • Trunk is silvery-gray and has horizontal lines (lenticels).
  • Dark-green, oval leaves are glossy and have toothed edges.
  • Largest specimen was transplanted in Autumn 2012 with help from a very large crane.

2)   Nothofagus solandri var. cliffortioides (Mountain Beech, Tawhairauriki)

  • Deep green, oval leaves have a pointed tip and rolled edges.
  • Grows in lowland mountain regions to about 65 feet.  At high altitudes, it forms a “goblin forest” where the trees are no more than 6 feet tall.
  • Two large specimens transplanted with crane in Autumn 2012.

3)   Griselinia littoralis   (New Zealand Broadleaf, Kapuka)

  • Found throughout most of New Zealand from sea level to 3000 feet.
  • Deep green, oval leaves are thick and very shiny, and this fast-growing plant is often used for hedging and shelter planting.
  • Species name ‘littoralis’ means “growing by the sea”, indicating tolerance of salt spray.

4)   Chionochloa rigida   (Narrow-leaved Snow Tussock), C. rubra  (Red Tussock)

  • Genus of Chionochloa, comprises of about 20 species – all but one are native to New Zealand.
  • Despite its name, C. rigida has a flowing habit reaching 3 feet with flowering stems reaching 5 feet.  Leaves dry out giving the plant an overall golden color.
  • C. rubra has reddish colorings with fine weeping leaves reaching 3 to 4 feet and flowering stems that rise just above the foliage.

5)   Phormium colensoi  (syn. P. cookianum) and P. tenax  (New Zealand Flax, Wharariki)

  • Both species native to New Zealand, P. colensoi is endemic;  both are widespread.
  • P. colensoi seed pods tilt downwards and twist in a spiral as they dry.  P. tenax seeds are held upright and do not twist when drying.
  • P. tenax is a larger plant with leaves reaching 9 feet and flowering stalk up to 15 feet compared to P. colensoi whose leaves reach 5 feet and flowering stalk is slightly taller at 6 feet.

September Color Appears at the Washington Park Arboretum

September 2nd, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (August 26 - September 8, 2013)

Selected cuttings from the Washington Park Arboretum (August 26 – September 8, 2013)


1)  Betulaceae          Carpinus japonica, Corylus colurna, Ostrya carpinifolia

  • Nut-bearing, often enclosed in interesting husks, cones or bracts.

2)  Fabaceae            Colutea orientalis

  • Legumes, which are dry fruit in pods that dehisce (open along a seam).

3)  Gunneraceae         Gunnera manicata

  • The fruit-bearing conical spike can reach 6 feet in length.

4)  Magnoliaceae        Magnolia grandiflora, M. officinalis var. biloba, M. sieboldii

  • Cone-like fruits, from green to red, open to display bright orange seeds.

5)  Myricaceae          Morella californica

  • The fruit is a drupe with a waxy coating that can be used to make candles.

6)  Myrtaceae           Callistemon sieberi

  • Bottlebrush seed capsules remain unopened until stimulated by fire.

7)  Paeoniaceae         Paeonia rockii, P. suffruticosa

  • Peony fruit pods will open when ripe to display black or bright red seeds.

8)  Proteaceae          Grevillea victoriae

  • The profusion of colorful fruit on this shrub outshines many flowering plants nearby.

9)  Rosaceae            Rosa corymbulosa, R. davidii, R. roxburghii, Sorbus splendida

  • Rosaceous fruit can be drupes, achenes, nuts, follicles, capsules and accessory fruits.

10)  Sapindaceae        Koelreuteria paniculata

  • Sapindaceous fruit can be berries, nuts, drupes, schizocarps, capsules or samaras.

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

August 25th, 2013 by Pat Chinn-Sloan

Selected cuttings from the Washington Park Arboretum (August 19 – 25, 2013)

1)    Aralia elata (Japanese Angelica Tree)

  • Natural range: Japan, Korea, Russian Far East
  • Can be a tree more than 30 feet tall. Ours are multiple suckers from a spreading root system.
  • Located north of the Wilcox footbridge (40-3W).

2)   Bupleurum fruticosum

  • A dense, multi-stemmed shrub tolerant of exposure and poor soil.
  • Native to Southern Europe and the Mediterranean.
  • Located in our Rock Rose area west of the Sorbus Collection (21-3E).

3)   Kalopanax septemlobus

  • A member of the Aralia family (Araliaceae), it grows to 100 feet. Its lobed leaves might be mistaken for maple until the umbels of flowers appear in July and August.
  • Native to Japan, Korea, and the Russian Far East.
  • Our best is located west of Azalea Way in 15-1W.

4)   Poliothyrsis sinensis

  • Native to the Chinese province of Hupeh
  • Bears clusters of fragrant white flowers
  • Located south of the Woodland Garden near other so-called primitive trees: Trochodendron, Tetracentron, and Euptelia.

5)   Rosa sp. with Spiny Rose Gall

  • These galls are caused by a tiny wasp, probably Dipolepis bicolor, which lays its eggs in the rose’s leaves. The larvae live in the galls until the following spring.
  • This plant is located in 25-1E at the intersection of the Upper and Lower Trails.

August Color Appears at the Washington Park Arboretum

August 2nd, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (7/29/13 - 8/12/13)

Selected cuttings from the Washington Park Arboretum (7/29/13 – 8/12/13)

“Can You Smell That Smell?”

1)   Clerodendrum trichotomum 
(Peanut-Butter Tree)

  • Repugnant, peanut-butter odor when leaves are bruised!
  • Cats are attracted to the smell.
  • See our suckering forest of young trees along the path leading down to the WPA horticultural crew barn.

2)   Prostanthera cuneata      (Alpine Mint-Bush)

  • This low-growing shrub is from Australia and is in the Mint family.
  • When leaves are crushed, they emit a strong fragrance that some liken to eucalyptol and smelly socks.
  • Located in the Australian exhibit of the Pacific Connections Garden.

3)   Ribes malvaceum var. viridifolium   ‘Ortega Beauty’      (Chapparal Current)

  • Native to the coastal mountains of southern California.
  • Malodorous skunky scent when leaves are rubbed like many plants in a chapparal community.
  • Located in the Cascadian entry exhibit of the Pacific Connections Garden.

4)   Umbellularia californica      (Headache Tree)

  • Large broadleaf evergreen tree.
  • Most odoriferous tree in our plant collections by far.
  • Take a deep whiff of the crushed leaves and you’ll know right away why it’s called the headache tree!

5)   Vitex agnus-castus      (Monk’s Pepper)

  • Peppery-smelling leaves some folks compare to Cannabis.
  • An ornamental summer-flowering shrub with many medicinal qualities.
  • Located along Azalea Way at the SE entrance to the Woodland Garden.

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

July 18th, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (July 15 - 31, 2013)

Selected cuttings from the Washington Park Arboretum   (July 15-31, 2013)

“Quirky Oaks”

1)   Quercus x bushii ‘Seattle Trident’
(Seattle Trident Hybrid Red Oak)

  • Cultivar of a Black Oak and Blackjack Oak hybrid.
  • Developed in Sir Hillier Gardens and Arboretum in England from scion wood collected at Washington Park Arboretum.
  • Located in the Oak Collection, northwest of Azalea Way service road intersection.

2)   Quercus dentata     (Daimyo Oak)

  • Asian native (China, Korea, Japan, Mongolia)
  • Develops an unusually large leaf; occasionally used as a vegetable in native range.
  • Located in the Oak Collection on hillside near Foster Island Road.

3)   Quercus macrocarpa       (Bur Oak)

  • Native to Eastern and Midwestern U.S.
  • Develops a distinct broad canopy as tree matures.
  • Located in the Oak Collection along ridge west of Azalea Way.

4)   Quercus muhlenbergii      (Chinquapin Oak)

  • Broad, native range spanning from New England to northeast Mexico.
  • Large, slow growing tree with chestnut-like foliage.
  • Located in the Oak Collection along ridge west of Azalea Way, north of the Bur Oak.

5)   Quercus pontica      (Armenian Oak)

  • Native to the Caucasus Mountain region of Eastern Europe.
  • Shrubby oak: leaves on new wood remain evergreen, yet older wood becomes deciduous.
  • Located in the Oak Collection near entrance to the Graham Visitor’s Center.

July Color Appears at the Washington Park Arboretum

July 6th, 2013 by Pat Chinn-Sloan

Chile in Seattle

Selected cuttings from the Chilean Gateway Garden in the Washington Park Arboretum (July 1 - 15, 2013)

Selected cuttings from the Chilean Gateway Garden in the Washington Park Arboretum (July 1-15, 2013)

1)  Alstroemeria sp.

  • Commonly called Peruvian Lily or Lily of the Incas.
  • The genus was named after Swedish baron, Claus von Alstroemer (1736-1794) by his close friend, Carolus Linnaeus.
  • Beautiful drifts grace the Chilean Gateway.

2)  Gunnera tinctoria

  • Sometimes referred to as Chilean rhubarb or dinosaur food.
  • The leaves can grow up to 2.5 meters across.
  • Several large clumps dot the Chilean Gateway hillside.

3)  Lobelia tupa

  • Its latex is used as an hallucinogen, which may explain its common name, Tobaco del Diablo.
  • The flowers are red, tubular and two-lipped and are produced in a sympodium pattern.
  • This wonderful perennial is in full bloom in the abundant Chilean Gateway Garden.

4)  Calceolaria integrifolia

  • Its puffy flowers give it its common names Slipperwort, Pocketbook Plant, Pouch Flower or Lady’s Slipper.
  • Can be transient in the garden because it is somewhat tender.
  • One big poofy plant is blooming profusely in the Chilean Gateway.

5)  Luma apiculata

  • Also known as Chilean myrtle. The Mapuche Native Americans call it “Kelumamull” or Orange Wood.
  • It is a slow-growing, evergreen tree with abundant white flowers and beautiful orange-grey bark.
  • We are fortunate to have several nice specimens in the Chilean Gateway planting.

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

June 21st, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (June 17 - 30, 2013)

Selected cuttings from the Washington Park Arboretum  (June 17 – 30, 2013)

1)  Callistemon sieberi            (Alpine Bottlebrush)

  • This small, spreading shrub is currently showing off its creamy-yellow flowers in bottlebrush-like spikes.
  • Native to Australia, C. sieberi can be found along the footpath of the Australian Entry Garden within the Pacific Connections Garden.

2)  Cytisus battandieri            (Pineapple Broom)

  • Sometimes referred to as Argyrocytisus, this genus of Brooms fall within the family, Fabaceae.
  • Native to Morocco, C. battandieri is an upright tree-like shrub with pineapple-scented flowers.
  • Located on the east side of Arboretum Drive in the Legumes.

3)  Liriodendron tulipfera         (Tulip Tree)

  • A member of the family Magnoliaceae, Liriodendron is a genus of two deciduous trees, L. chinense and L. tulipfera.
  • The solitary, cup-shaped flowers, inconspicuous from a distance, add interest in summer, but are not produced on young plants.
  • Located in the Magnolias, these cuttings came from a tree over 100 feet tall.

4)  Staphylea pinnata             (European Bladdernut)

  • The flowers of this upright shrub have come and gone, but it is the curious bladder-like fruit now on display.
  • Located near Azalea Way amongst the True Ashes.

5)  Tsuga sieboldii                (South Japan Hemlock)

  • Glossy, dark green foliage and smooth, dark gray bark give this tree some distinction within its genus.
  • This Tsuga can be found between the Woodland Garden and the top of Loderi Valley.

June Color Appears at the Washington Park Arboretum

June 10th, 2013 by Pat Chinn-Sloan
Selected cuttings from the Washington Park Arboretum (June 3 - 16, 2013)

Selected cuttings from the Washington Park Arboretum  (June 3 – 16, 2013)

1)  Illicium henryi     (Henry’s Star Anise)

  • This Chinese Illicium is a standout of the genus, as most anise have white or cream-colored flowers.
  • I. henryi can be found along the foot path of the Sino-Himalayan Hillside as well as along the Ridgetop Trail, just west of the Magnolia Collection.

2)  Kalmia latifolia     (Mountain Laurel)

  • This under-used Rhododendron relative is native to the eastern United States.
  • The color of the closed flower buds is often completely different from the open flower color, which ranges from white to deep red, often with a distinctive band inside.
  • There are several cultivars of K. latifolia in the Woodland Garden.

3)  Leptospermum scoparium     (Manuka, New Zealand Tea Tree)

  • The bloom of manuka is profuse and long lasting.
  • Captain Cook supposedly brewed tea for his crew using manuka, which is rich in vitamin C.
  • Specimens can be found in the Australian portion of the Pacific Connections Garden.

4)  Quercus robur  ‘Concordia’     (Golden English Oak)

  • The golden color of the young growth fades to green as the leaf ages.
  • Our specimen can be seen on Azalea Way just south of the Graham Visitors Center.

5)  Rhododendron  ‘Teddy Bear’

  • This cultivar of Rhododendron is a cross between R. bureavii and R. degronianum ssp. yakushimanum.
  • The thin white indumentum on the upper side of the leaf goes away in time, while the thick indumentum of the underside remains and turns brown.
  • This Rhododendron can be found in the Puget Sound Rhododendron Hybridizers Garden along Azalea Way.