A Subtle Side of Spring

March 28th, 2016 by UWBG Horticulturist

Spring is not typically known for its subtlety around these parts, but upon its early awakening many plants warrant a closer look. Enjoy!

Selected cuttings from the Washington Park Arboretum, March 21, 2016 - April 4, 2016

Selected cuttings from the Washington Park Arboretum,
March 21, 2016 – April 4, 2016

1)  Acer palmatum ‘Katsura’                     Katsura Maple

Close-up of Acer palmatum 'Katsura'

Close-up of Acer palmatum ‘Katsura’

  • One of the first Japanese maples to leaf out each spring. The small, five-lobed leaves emerge pale yellow-orange, with brighter orange margins.
  • Found in the semi-dwarf group of Japanese maples.
  • Specimen 19-10*A is located in grid 30-4E.

2)  Ginkgo biloba                     Maidenhair Tree

  • Emerging leaves are “mini-mes” of the actual size.
  • Also seen are emerging male cones.
  • This sample is taken from the Graham Visitor Center specimen located in the northwestern corner of the parking lot.

3)  Larix laricina                     Tamarack or Eastern Larch

  • Deciduous conifer native to eastern North America
  • Cutting sample shows newly emerging needles and last year’s cones.
  • Specimen is located in grid 33-5W, Pinetum.

4)  Photinia beauverdiana var. notabilis

  • Rose family deciduous shrub from China
  • Hairy, white newly-emerging leaves and flowers on cutting sample
  • Specimen is located in grid 33-5W, Pinetum.

5)  Ribes sp. (maybe R. menziesii)                     Gooseberry (maybe Canyon Gooseberry)

  • Though this Ribes sp. has not been positively ID’d, it is indeed a gooseberry because it has spines.
  • Not the eye-catching Ribes sanguineum flowers, but beautiful nevertheless.
  • Thicket is located behind the Stone Cottage.

March 2016 Plant Profile: Abies grandis

March 1st, 2016 by UWBG Horticulturist

By Ryan Garrison, UW Botanic Gardens Horticulturist

There is a tree on the bank of Arboretum Creek that has seen the entire history of the Washington Park Arboretum, being almost certainly a legacy of the historic site vegetation.1 The seed that would eventually become this giant likely fell to the ground about the year 1896 when the site was logged by its previous owner, the Puget Mill Company.  It would have been a tiny seedling when the land was acquired by the City of Seattle in a series of purchases in 1900 – 1904. It probably went unnoticed by John C. Olmsted and his assistant, Percy Jones, when they arrived in Seattle on April 30, 1903.2 Within a month they had outlined a plan for the City’s future park system, including Lake Washington Boulevard, a mere stone’s throw from this tree. It somehow managed to survive the myriad trials that a tree must overcome to reach maturity. It has endured such adversities as snowstorms, temperatures as low as 0°F, and hurricane force winds. Through it all, it has reached inexorably upwards, and now towers above everything around it.

Grand_fir_398

This remarkable tree is known as a Grand fir (Abies grandis), and this particular specimen truly lives up to its common name. Grand fir grows in the stream bottoms, valleys, and mountain slopes of the northwestern United States and southern British Columbia.3 It is not for board feet, but for its beauty that this tree is valued. The wood is too soft, yet too heavy in proportion to its little strength, to make first class lumber. Pulpwood offers its only commercial future, and there are so many finer pulping species that Grand Fir is little felled for any purpose and is usually left in the forest to make music and distill incense.4

Grand_fir_combo_598

Common Name: Grand, White, Silver, Yellow, or Stinking Fir

Location:  The bank of Arboretum Creek, in grid # 22-4W. It can be seen from many places in the Arboretum, towering over its neighbors.

Origin: Northwestern United States and southern British Columbia

Height and Spread: On optimum sites in the coastal lowlands of Washington, mature grand firs reach heights of 43 to 61 m (140 to 200 ft) at 51 to 102 cm (20 to 40 in) d.b.h.; occasionally they reach 76 m (250 ft) in height and 152 cm (60 in) in d.b.h.  This tree is approximately 140 feet tall and 4.1 feet in diameter.

Bloom Time: Time of flowering may vary over several months, depending on temperatures during the weeks preceding flowering. Flowering occurs from late March to mid-May at lower elevations of most coastal locations, and in June at the higher elevations of the inland locations. The cones, mostly yellowish-green and occasionally greenish-purple, ripen from August to September of the same year, and seeds are dispersed approximately 1 month later.

 

  1. Hitchin, R., “The native forest vegetation in the Washington Park Arboretum: community analysis and curatorial recommendations”, (MA thesis, University of Washington, 1998), 49.
  2. Washington Park Arboretum Historic Review, September 2003.
  3. http://www.na.fs.fed.us/pubs/silvics_manual/Volume_1/abies/grandis.htm
  4. Peattie, Donald Culross, and Paul Landacre. A Natural History of North American Trees. Boston: Houghton Mifflin, 2007.

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

February 29th, 2016 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum (February 22, 2016 - March 7, 2016)

Selected cuttings from the Washington Park Arboretum
(February 22, 2016 – March 7, 2016)

1)  Chaenomeles cathayensis                   Chinese Quince

  • This deciduous shrub is native to slopes and forest margins in western Hubei Province.
  • Light pink flowers in spring are followed by large oblong fruit which are unpalatable raw, but make fragrant jams and jellies when cooked.
  • Like other quince, Chaenomeles cathayensis’ arching branches are armed with stiff thorns.
  • Two specimens can be seen in the old field nursery south of the Crab Apple Meadow near Arboretum Drive.

2)  Corylopsis glabrescens         Japanese Winter Hazel

  • A broadly-spreading deciduous shrub native to Korea and Japan, this plant is noted for its graceful habit and fragrant yellow flowers in late winter.
  • A relative of witch hazel, Corylopsis are a great way to extend the bloom time of the winter landscape.
  • Some beautiful specimens can be seen on the trail to Azalea Way, west of the Witt Winter Garden.

3)  Cryptomeria japonica  ‘Nana’                     Dwarf Japanese Cedar

  • Introduced to England from China by Robert Fortune in 1842, this slow-growing conifer is one of the earliest cultivars.
  • Our specimen, planted in 1960, is located north of the grove of Sequoia sempervirens in the Pinetum.

4)  Osmanthus x burkwoodii                      Hybrid Sweet Olive

  • A hybrid of Osmanthus delevayi and Osmanthus decorus, this large evergreen shrub boasts the beauty of the former with the toughness and adaptability of the latter.
  • Small tubular white flowers exude a powerful jasmine fragrance in spring.
  • Several specimens can be seen along Foster Island Drive near the entrance to the maintenance yard.

5)  Sequoia sempervirens  ‘Henderson’s Blue’                    Henderson’s Blue Coast Redwood

  • This vigorous, blue-gray needled tree is a cultivar of the species native to the central and northern California coast.
  • The species is in the family Taxodiaceae, which also includes Sequoiadendron giganteum and Taxodium distichum, two important North American natives.
  • Located north of the grove of Sequoia sempervirens in the Pinetum.

February Color Appears at the Washington Park Arboretum

February 14th, 2016 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum, February 8 - 21, 2015

Selected cuttings from the Washington Park Arboretum,
February 8 – 21, 2015

1)  Pinus greggii

  • This three-needle pine from northeastern Mexico is closely akin to P. patula but less ornamental.  Its oval-conical cone clusters stay closed on the branch for several years.  This specimen and the others described here can be found within Crabapple Meadow, along the east side of Arboretum Drive.

2)  Pinus jeffreyi

  • Native mainly of California in the Sierra Nevada and Siskiyous, this lofty tree is said to grow to 200 feet in the wild.  P. jeffreyi is closely allied to P. ponderosa and at one time, it was normal to regard it as a variety of that species.  Its three-needle bundles are said to give off a fruity scent when bruised.
Close-up of cones from Pinus greggii

Close-up of Pinus greggii cones

3)  Pinus montezumae var. lindleyi

  • This five-needle pine is native to southern and central Mexico at subtropical and cool temperate altitudes, with its best development at 7,000 to 8,000 ft.  Its flexible, pendulous leaves (growing to 14 inches or longer) along with its broad, dome-shaped crown give it a distinct look.

4)  Pinus pinaster

  • Commonly known as the Maritime Pine, this specimen is native to southwestern Europe and north Africa.  The glossy green leaves of this pine are the largest and stoutest of all two-needle pines, and it is said to be one of the best for light sandy soils.  As its common name implies, it thrives in coastal maritime localities.

5)  Pinus strobus ‘Fastigiata’

  • A native of eastern North America, P. strobus has proven to be a valuable timber tree and one of the richest assets of our country.  Its bluish-green five-needle clusters are three to five inches long, with lines of white stomata on the inner sides.  Once again, all of these specimens listed here can be found within Crabapple Meadow, along the east side of Arboretum Drive.

Late January Color Appears at the Washington Park Arboretum

January 31st, 2016 by UWBG Horticulturist

Sleeping Beauties

Selected cuttings from the Washington Park Arboretum (January 25 - February 7, 2016)

Selected cuttings from the Washington Park Arboretum
(January 25 – February 7, 2016)

1)  Oemleria cerasiformis                Indian Plum

  • The Indian Plum adheres to Benjamin Franklin’s advice in Poor Richards Almanac: “Early to bed, early to rise. . . .”  This shrub goes to sleep early, beginning to slowly defoliate in late summer.  However, it is one of the first to leaf out, and flowers early in the spring.  It can be found throughout the Arboretum, and is just beginning to awaken.

2)  Ophiopogon planiscapus ‘Nigrescens’                          Black Mondo Grass

3)  Magnolia × soulangeana                Saucer Magnolia

  • The Saucer Magnolia wraps its flower buds in a fuzzy blanket for its winter nap.  As winter draws to a close and spring approaches, these buds will swell and open into a glorious pink and white show.  You can find this and many other specimens of this wonderful genus in our nationally-recognized Magnolia Collection (http://depts.washington.edu/uwbg/gardens/wpa/collections.php).

4)  Polystichum munitum                Western Sword Fern

  • The Western Sword Fern spends its winter in a tightly coiled bunch.  As they unfurl in spring, these are called fiddleheads, as they resemble the curled ornamentation (called a scroll) on the end of a stringed instrument, such as a violin.  Fiddleheads also just happens to be the name of the UW Botanic Gardens’ Nature Preschool Program (http://depts.washington.edu/uwbg/education/Youth/nature_preschool.shtml).

5)  Tsuga heterophylla                Western Hemlock

  • Not all the plants in the Arboretum are providing shade for Little Nemo in Slumberland.  Some plants, such as conifers like the Western Hemlock, do not go to sleep during the winter.  As long as it is not too cold, they will happily photosynthesize, converting water and air into sugar.

January Color Brings in the New Year at the Washington Park Arboretum

January 16th, 2016 by UWBG Horticulturist
Selected cuttings from the Witt Winter Garden at the Washington Park Arboretum (January 11-24, 2016)

Selected cuttings from the Witt Winter Garden at the Washington Park Arboretum (January 11-24, 2016)

Witt Winter Garden

1)  Cornus sanguinea ‘Midwinter Fire’
Midwinter Fire Dogwood

  • Though the species normally has red twigs and purple fall color, this outstanding cultivar has golden-yellow fall color followed by red-blushed, yellow twigs.
  • This dogwood is native to northern Europe into northwestern Asia.
  • Full sun is required to obtain the best winter stem color and this dogwood will slowly colonize an area via suckers from its shallow roots unless controlled.

2)  Corylus maxima  ‘Atropurpurea Superba’                Purple Giant Filbert

  • This excellent selection of the Giant Filbert produces long purple catkins in winter followed by large purple-red leaves in spring.
  • From what we have observed in the Witt Winter Garden, this specimen is resistant to eastern filbert twig blight, caused by the fungus Anisogramma anomala.

3)  Daphne bholua  ‘Jacqueline Postill’                Lokta, Paper Daphne

  • The specific epithet “bholua” comes from “bhulu swa”, the Nepalese name for the species.
  • Despite having a native range to 12,000 feet in the Himalayas, this species of Daphne is just as hardy in Seattle and requires a protected placement in the garden.

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

  • The north end of the Witt Winter Garden contains many species and cultivars of witch hazel.
  • Witch hazel flowers range from sulfur-yellow to carmine-red, while their fragrance can be absent, lightly floral or an intense citrus.

5)  Sarcococca hookeriana var. digyna                Sweet Box

  • Sweet box is an often overlooked element of the Witt Winter Garden due to the diminutive size of its flowers, though no one can miss their intense fragrance.
  • Perfectly comfortable in dry shade, Sweet Box is an excellent choice for under-planting taller shrubs or small trees such as Hamamelis.

Deck the Halls

December 22nd, 2015 by UWBG Horticulturist

Boughs used as winter decoration are often from plants in the genus Ilex. Many Ilex, or holly species are dioecious, meaning that male and female reproductive organs are separated on individual plants. This trait promotes cross-fertilization which increases genetic variability, but can decrease seed-setting efficiency.  Solitary individuals are unable to be pollinated, therefore it is necessary that male and female plants grow in close proximity or female plants will not produce berries.

Selected cuttings from the Washington Park Arboretum (December 15 - 28, 2015)

Selected cuttings from the Washington Park Arboretum (December 15-28, 2015)

1)  Ilex cassine var. mexicana

  • This large, fast-growing evergreen is native to the southeastern coast of the U.S. as well as Mexico, Puerto Rico and Cuba.
  • A healthy specimen can be found in grid 13-3W, just west of Lake Washington Boulevard.

2)  Ilex verticillata  ‘Red Sprite’

  • This female, deciduous Ilex cultivar reveals large red berries when its leaves fall.
  • Our best patch can be found along the path in the Joe Witt Winter Garden planted next to the male pollinizer, Ilex verticillata ‘Jim Dandy’.

3)  Ilex opaca  ‘Boyce Thompson Xanthocarpa’

  • Evergreen tree that grows rapidly and assumes an attractive conical shape. As with most of the American Holly clade, this tree is cold hardy but not very wind-tolerant.
  • Berries can be crimson-red, yellow or orange.

4)  Ilex opaca  ‘Emily’

  • Found in the Pacific Connections Meadow plantings, this evergreen female boasts copious quantities of vivid red fruits, starting at a very young age.

5)  Ilex serrata

  • Located in the deciduous Holly clade on the west side of Lake Washington Boulevard, this holly spreads and suckers to form colonies.
  • Small red berries are revealed in late autumn after the leaves have fallen.

December Color Appears at the Washington Park Arboretum

December 11th, 2015 by UWBG Horticulturist

Conifer trees occasionally mutate into unusual forms, often slow-growing natural dwarfs. Thousands of these have been in cultivation for centuries. The Arboretum has only a few in its collection, sadly neglected in grid 37-1W – a corner of the Oaks area.  Here are five examples:

Selected cuttings from the Washington Park Arboretum (December 1 - 14, 2015)

Selected cuttings from the Washington Park Arboretum (December 1 – 14, 2015)

1)  Chamaecyparis lawsoniana  ‘Lycopodioides’

  • Translated: “a form of Lawson’s false cypress that looks like Lycopodium” – a genus of club moss that’s said to resemble a wolf’s foot.

2)  Chamaecyparis pisifera  ‘Plumosa Nana’                     Dwarf Sawara Cypress cv.

  • Dwarf (nana), feathery (plumose), pea-bearing (pisifera) false cypress

3)  Cryptomeria japonica  ‘Bandai-Sugi’                     Japanese Cedar cv.

  • The cultivar name has been shortened recently to ‘Bandai’ because Sugi is the Japanese word for Cryptomeria, therefore is redundant.
  • All parts of the flower are hidden in this genus, hence Crypto (hidden) meria (parts).

4)  Picea abies  ‘Gregoryana parsonii’                Norway Spruce cv.

  • See Arthur Lee Jacobson’s Trees of Seattle for an explanation of the botanic name.
  • Jacobson notes that only Lawson’s Cypress has more cultivars than Norway Spruce.

5)  Tsuga canadensis  ‘Hussii’                Eastern Hemlock cv.

  • Because of people’s tendency to call all conifers “pine” or “fir”, botanists adopted the Japanese name for hemlocks – Tsuga.  Does that sound too similar to ‘Sugi’?

“Happy Thanksgiving!”
Native Plants of Cape Cod

November 23rd, 2015 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum, November 16 - 29, 2015

Selected cuttings from the Washington Park Arboretum, November 16 – 29, 2015

1)  Arctostaphylus uva-ursi                                                   ‘Vancouver Jade’            Kinnikinnick or Bearberry

  • Broadleaf evergreen and creeping groundcover with circumpolar distribution in northern hemisphere often found growing in association with Pitch Pine
  • If there were still bears on Cape Cod, it would be a favorite food source for them.
  • This cultivar, ‘Vancouver Jade’ is growing in containers outside the Graham Visitor Center.

2)  Juniperus virginiana  ‘Blue Coast’                               Eastern Red Cedar

  • A low growing, blue form of the Eastern Red Cedar
  • Pioneer species found in mixed stands with Pitch Pine, reclaiming abandoned farms and grasslands
  • Found growing under Pines in grid 36-4E, along nursery road

3)  Morella pensylvanica                Bayberry

Photo demonstrating the straightness of Arrowwood stems and their usage in making arrows

Photo demonstrating the straightness of Arrowwood stems and their usage in making arrows

  • Berries boiled to extract sweet-smelling wax used to make clean-burning candles
  • Found growing in dry open sites along with Bearberry, Eastern Red Cedar and Pitch Pine
  • Mass growing in Oaks Collection in grid 43-B

4)  Pinus rigida                Pitch Pine

  • Rigid cone scales and stiff needles, hence its Latin specific epithet
  • Used during days of wooden ships due to its resistance to decay
  • Several young specimens in our Pinetum, grid 37-4W

5)  Viburnum dentatum var. pubescens                Arrowwood

  • Large deciduous shrub with fruit a food source for songbirds
  • Common name refers to Native American use of straight young stems as arrow shafts
  • Old specimens located in southeastern Viburnum bed, grid 24-4W

Reference: http://www.na.fs.fed.us/pubs/

 

 

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

October 20th, 2015 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum (October 19, 2015 - November 1, 2015)

Selected cuttings from the Washington Park Arboretum (October 19, 2015 – November 1, 2015)

1)  Cupressus (Hesperocyparis) bakeri                               Modoc Cedar

  • A moderately-sized coniferous tree with greyish-green scale-like foliage that is dotted with white resin. It is native to the Siskiyou and Sierra Nevada Mountain ranges. A slow growing tree, usually under 90 feet over many decades.
  • Considered vulnerable to extinction in the wild in the medium term.
  • Located in the Pacific Connections Garden Cascadia Focal Forest above the Chilean Gateway.

2)  Euonymus myrianthus                Evergreen Spindle Tree

  • A member of the same family as burning bush, this large shrub was discovered in western China and introduced into cultivation by famed plantsman, E.H. Wilson.
  • This plant has insignificant flowers in spring and bares conspicuous yellow fruit in fall, which persist well into winter.
  • Located with the Asiatic Maples collection, north of where the upper and lower trails meet.

3)  Notholithocarpus densiflorus var. densiflorus                Tan Oak

  • Native to the mountains from southwestern Oregon through central California.
  • A natural source of tannin, Tan Oak bark was used in the process of tanning leather.
  • This species is particularly susceptible to “sudden oak death” Phytophthora ramorum.
  • Located in Pacific Connections Garden Cascadia Focal Forest above the Chilean Gateway.

4)  Picea breweriana                             Brewer’s Weeping Spruce

  • Native to the Siskiyou Mountains, this large coniferous tree is slow growing and adapted to extreme cold. The tough flexible branches are held horizontally, forming curtains of foliage. The stiff flattened needles are dark green with two white bands of stomata on the undersides.
  • Located in the Pacific Connections Garden Cascadia Entry Garden near Arboretum Drive.

5)  Magnolia grandiflora ‘Monlia’                Southern Magnolia

  • A medium-sized evergreen tree to 50 feet, it has large green leaves with brown indumentum covering the undersides. Large fragrant white flowers in summer are followed by large upright fruit. The species is native to the southeastern United States.
  • Located at the south end of the Graham Visitors Center parking lot.