April Color Appears at the Washington Park Arboretum

April 10th, 2016 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum, April 4 - 17, 2016

Selected cuttings from the Washington Park Arboretum,
April 4 – 17, 2016

1)  Acer mandshuricum                Manchurian Maple

  • The Manchurian Maple is native from Eastern Siberia into China and strongly resembles Acer griseum and Acer triflorum.
  • This species is located in the Asian Maples Collection.

2)  Distylium racemosum                Isu Tree

  • The flowers of Distylium racemosum are petalless, but have attractive red calyces (whorl of sepals) and purple stamens.
  • The Isu tree is native to southern Japan, but can be found in the Witt Winter Garden and in our Hamamelidaceae Collection, east of Arboretum Drive near the Pacific Connections gardens.

3)  Pieris japonica                Lily-of-the-Valley Shrub

  • This shrub from eastern China, Taiwan and Japan begins the spring with showy terminal panicles of flowers that range from white to dark-red, followed by extremely colorful new growth which will fade to green in summertime.
  • Lily-of-the-Valley can be found at the Graham Visitor Center, the Witt Winter Garden and Rhododendron Glen.

4)  Rehderodendron macrocarpum

  • This native of southwestern China and Vietnam is a member of the Styracaceae family and displays typical Styracaceous white pendent flowers in Spring.
  • Though a relatively small tree in the Pacific Northwest, Rehderodendron macrocarpum is a dominant component in its native habitat.
  • Specimens can be found along Azalea Way near our Puget Sound Rhododendron hybridizers bed as well as in the Witt Winter and Woodland Gardens.

5)  Viburnum bitchuense                Bitchiu Viburnum

  • This native of Korea and Japan has pink buds that open to wonderfully fragrant white flowers.
  • Viburnum bitchiuense can be found just across Arboretum Drive, outside the east doors of the Graham Visitor Center.

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.

Glimpse into the past – A Tale of Two Kames

March 27th, 2016 by Jessica Farmer, Adult Education Supervisor

Almost no one is aware that the Washington Park Arboretum is the location of two kames. “Kames, what is that?” everyone asks. Wikipedia tells us that “a kame is a geomorphological feature, an irregularly shaped hill or mound composed of sand, gravel and till that accumulates in a depression on a retreating glacier.”

Located just east of Lake Washington Boulevard E. and just north of the intersection with Boyer Avenue S., the two kames were given the names Honeysuckle Hill and Yew Hill. They were originally the planting sites of collections for plants in these families. To clarify the taxonomy, this is the Caprifoliaceae/Adoxaceae (Honeysuckle/Adoxa) family. If you find a plant with opposite leaves and pithy stems (the inside of the stem looks like stryofoam), this is the family. The yew family is known as the Taxaceae family, a coniferous family which includes mostly smaller evergreens. These site names were originally noted on the 1936 Dawson Plan for the Arboretum, completed by the Olmsted Brothers firm.

View across Azalea Way, west to Honeysuckle mound. April 14, 1948

View across Azalea Way, west to Honeysuckle mound. April 14, 1948

The photo above depicts a view looking west across Azalea Way, toward Honeysuckle Hill, on April 14, 1948. Notice that there is very little vegetation along Azalea Way, and the kame has been almost entirely mowed and covered with grass. A few remnant native trees remain. (Note: the photographs labeled by then-director Brian O. Mulligan called them mounds rather than hills or kames.)

View north from Honeysuckle mound to Yew mound. April 7, 1959

View north from Honeysuckle mound to Yew mound. April 7, 1959

The second photo, taken on April 7, 1959 (ten years later), is a view north from Honeysuckle Hill toward Yew Hill. Notice already how much taller the trees are and how many more trees are present. Today, these kames are almost entirely obscured by the vegetation and barely noticed by visitors. Nevertheless, they are an important geological legacy in the Arboretum.

 

Construction Started to Expand Public Access at Arboretum

March 25th, 2016 by UWBG Communication Staff

Photo: The Berger Partnership Whether you’re a first-time visitor to the Washington Park Arboretum or have been coming to the gardens for decades, a new trail project will take you through plants you likely haven’t seen here before.

Construction has begun on the new Arboretum Loop Trail. Once finished, this paved, multi-use 1.2-mile trail will connect to Arboretum Drive, creating a highly accessible 2.5-mile path through plants and trees from around the world—many of which are rare or threatened species. The paved path will create more opportunities for pedestrians, wheelchair users, slow-moving bicycle riders and families with strollers to exercise and explore once-hidden parts of the Arboretum year-round.

Much of our work will benefit existing plant collections by adding new specimens, replanting with native species that provide richer food and shelter for wildlife, and removing unhealthy and invasive plants. Portions of Arboretum

Detail of the construction map. Source: City of Seattle

Detail of the construction map. Source: City of Seattle

Creek will be day-lighted, and important wetland habitat will be restored.

Throughout planning, design and construction, the health of Seattle’s flagship public garden has been a top priority. We moved what we could, propagated what we couldn’t, and rerouted the Loop Trail to protect rare, unusual or very large trees that could not be moved. In total, just 137 of the Arboretum’s 10,000+ trees will be removed, and we intend to reuse all of the tree material onsite in restoration projects and other work.

As part of mitigation for the current phase of the SR 520 bridge project, the Washington State Department of Transportation is providing $7.8 million to help complete portions of the arboretum’s 20-year master plan, which was adopted in 2001 after years of public input. This paved path is a jewel of the master plan.

More information is available on the City of Seattle project site.

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.

Glimpse into the past – Seeps and shifting soils

February 3rd, 2016 by Jessica Farmer, Adult Education Supervisor

by John A. Wott, Director Emeritus

Last month we discussed how rapidly trees grow and change the landscape.  It is interesting how physical landscapes also change and often actually shift and move due to changes in temperatures. Visitors to the Pacific Connection Gardens, specifically the New Zealand Forest, have seen the renovation of the Lookout which restored its former shape and size. It is perched high above a steep bluff which looks northward over Azalea Way and the large pond with the University of Washington in the distance.

The steep wall was buttressed by stone work, and originally a pathway allowed visitors to precariously descend from the area of the Lookout to the green grassy basin surrounding the pond.

Bank before reconstruction, 7/2/1967

Bank before reconstruction, 7/2/1967. Photo by B. O. Mulligan.

This entire hillside “sheds” much water and after every rain, it is quite squishy and treacherous. In fact, sometimes you can even see slippage cracks. The Works Progress Administration men laid a series of wooden pipes to assist in drainage but these have almost totally failed. Thus it has been a challenge to manage this entire rockery and drainage system.

Originally built in the 1940s, the photos shown here detail a reconstruction project of the bank and pathway in July 1967. The first photo above is before reconstruction.  The others detail the new path and stone work, all taken on July 13, 1967.

Upper portion of new steps, 7/14/1967. Photo by B.O. Mulligan.

Upper portion of new steps, 7/14/1967. Photo by B. O. Mulligan.

 

New steps down bank, 7/14/1967. Photo by B.O. Mulligan.

New steps down bank, 7/14/1967. Photo by B. O. Mulligan.

 

New steps constructed on bank, 7/13/1967. Photo by B. O. Mulligan.

New steps constructed on bank, 7/13/1967. Photo by B. O. Mulligan.

 

Top of bank after clearing and new rock work. Photo by B. O. Mulligan.

Top of bank after clearing and new rock work. Photo by B. O. Mulligan.

As you can see, it has very uneven steps, typical of the designs of that day. Over the years, there have been many slippages and the path has been closed due to safety issues.  Currently there is no easy way to ascend/descend that slope.

The current photo taken on January 24, 2016, shows a view of the rockery which obscures most of its beauty.

Current view of rockery, Lookout above, 1/24/2016. Photo by John A. Wott.

Current view of rockery, Lookout above, 1/24/2016. Photo by John A. Wott.

The last photo shows water gushing from old pipes and seepage ways.

Water gushing from hill side and banks, 1/24/2016. Photo by John A. Wott.

Water gushing from hill side and banks, 1/24/2016. Photo by John A. Wott.

UW Botanic Gardens staff is currently reviewing this entire area in order to restore its integrity, handle the drainage issues, and eventually make it all more easily accessible.

 

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.

February 2016 Plant Profile: Taiwania cryptomerioides

January 29th, 2016 by UWBG Communication Staff

By Ray Larson, Curator

Coffin tree branchesWhile there is an abundance of early blooms, bright bark and fragrance elsewhere in the Arboretum this time of year (particularly in the Winter Garden and Camellia Collection), winter is also a time to appreciate conifers.  One of the best and most unusual for foliar effects in February is Taiwania cryptomerioides, the Coffin tree.  We have three accessions totaling 8 trees in the Arboretum.  There are two from 1969 (Accession #315-69 A&B), four from 1996 (Accession #119-96 A-D) and two in the old nursery from 1974 (Accession #465-74 B&C).  The 1969 accessions are just south of the main Sequoiadendron grove just off Arboretum Drive E, and the 1996 plantings are at the Newton Street entrance in the Pinetum.  Using the interactive map on our website is a great way to easily locate plants.

From a distance Taiwania cryptomerioides looks a little in habit like a young western red cedar or false cypress.  But closer in its visual affinity to Cryptomeria becomes more apparent, hence the specific epithet meaning “resembling a Cryptomeria,” or Japanese cedar.  The Coffin tree is the only species in the genus Taiwania and hence is known as a monotypic genus.  The common name comes from the practice of some native peoples in its natural range using the trees for making coffins.  A tree is chosen at birth to be carved into a person’s coffin in old age.   The grove in the Pinetum is part of the ½ mile long interpretive trail, and selected specimens along the route feature information about the tree and its uses in small interpretive panels.

Coffin tree grouping

In older forests, trees with trunks up to 10 feet wide are not uncommon.  However the species is listed as Vulnerable to extensive logging in its native range.  Populations 500 years ago were much more robust and widespread.  The species is long-lived, and some older populations in Taiwan are now protected.

Ornamentally the tree has much to offer.  Perhaps most striking is the array of blue-green needles along the somewhat drooping branches.  They look sharp and stiff, but are surprisingly soft and flexible.  The textural effect is outstanding, and the narrow shape accentuates the somewhat weeping effect.  It is most attractive throughout the winter and spring seasons, and new growth is a brighter blue.  Like many conifers, older foliage does turn a brownish yellow before dropping, and this is usually most noticeable in late summer and early fall.  It does best in full sun.  In its native lands, it grows in mid to upper elevations in areas of summer and autumn rainfall but drier winters.  Despite this, it seems to do very well for us with our dry summers and wet winters.

Coffin tree needles

Next time you are in the Pinetum or near the giant Sequoias along Arboretum Drive, be sure to look for this species.  The ones at the Newton Street entrance are probably easiest to find, and if you haven’t been to this minor entrance from the Montlake Neighborhood, you’ll notice is reached from a quiet street end.

Common name:  Coffin tree
Family:  Cupressaceae
Location:  Grids 19-4E in the Sequoiadendron section, Grids 33-7E and 34-7E in the Pinetum at the Newton Street entrance
Origin:  Taiwan, northern Vietnam, Myanmar (Burma) and Yunnan, China.  Populations elsewhere in south-central China are believed to have been introduced.
Height and spread:  A large tree, that can reach over 200 feet in the wild.  It is fairly narrow in youth, and in cultivation is slower growing.  Considered the largest tree native to Asia
Hardiness:  Cold hardy to USDA Zone 8

Coffin tree with sign