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.

Coniferous Trees Highlighted in January Tours

January 6th, 2016 by Catherine Nelson, Adult Tours Program Assistant

When the Olmsted Brothers first came to the Seattle area in the early 1900s, they were impressed by the size, abundance and beauty of our native conifers. Thirty years later when they designed the collection placement for the Washington Park Arboretum, they made a point of not removing our native trees, but placing the arboretum collection within a matrix of these native conifers. Eighty years later our park abounds with these tall stately beauties.

Many of the first conifers – or (mostly) evergreen trees – acquired in the collection were placed on Foster Island at the north end of the park; this site, while picturesque, turned out to be not so good for the needs of the trees themselves. Now much of our conifer collection resides in the Pinetum, which meets the needs of these plants as it is a site with better sun exposure and soil drainage. The rest of the collection is placed throughout the arboretum in areas suited to the needs of each species.

cupressusguadaloupensisCurrently the UW Botanic Gardens conifer collection includes 41 genera of conifers, comprising 216 species (not including subspecies or varieties) and approximately 2,974 individual plants. Our Sunday Free Weekend Walks in January will focus on this extensive conifer collection. With close to three thousand plants in the collection we cannot see all of them in the 90 minutes allotted, but our guides will show and talk about many of these amazing trees as well as what makes them unique in the plant world.

CguadaloupensisOne of the conifers in our collection that I have come to admire is the Cupressus guadaloupensis var. guadaloupensis, common name Guadaloupe Cypress. We acquired three of these trees in 1989 and two are still living; these plants highlight the conservation value of our collection.

Our Guadaloupe Cypress are not very big and sit unassumingly next to a path in the Pinetum. This tree caught my eye because if its exfoliating bark, which I had never seen on a conifer before, so of course I had to do some research on this tree. I’m glad I did, because it is an interesting story.

These conifers are endemic to Guadaloupe Island in the Pacific Ocean west of the California/Mexico border. Guadaloupe is a desert island and most of its moisture is received through ocean fogs rather than rain. The Guadaloupe Cypress has been cultivated since the 1800s but is rarely used in collections as it will not set seed outside its native habitat and is not necessarily resistant to cold temperatures. In the last century the tree became critically endangered in its native habitat due to a population of feral goats on the island.

A quote from The Gymnosperm Database at Conifers.org:

“For many years the species was severely limited by the grazing of goats, which reduced its population to about 3300 individuals on about 160 ha, with negligible regeneration. However, in 2005, under the leadership of Dr. Alfonso Aguirre Muñoz, the Grupo de Ecología y Conservación de Islas, A.C. succeeded in completely eradicating the goats from this large island and the trees and vegetation are now recovering. This is an uncommon bit of good news in the generally depressing landscape of rare conifer conservation.” Good news indeed.

Arboretum Map Upgraded for Smartphones

January 5th, 2016 by Tech Librarian, Tracy Mehlin
map screenshot

The map home screen shows gardens and the highlighted collections plus parking lots. Zoom in to see plant icons.

Have you even been deep inside Rhododendron Glen at the Washington Park Arboretum and wondered which direction you should walk to get to the Lookout Gazebo? Or maybe you were standing in front the most floriferous Hydrangea you have ever seen and can’t find the identification label? If you have a smartphone in your pocket then you can use the freshly upgraded map to see where you are and what plants are near by. You can also search for plants by name, keyword or accession number. Once you find a plant you love add it to your favorites. Next time you visit the Arboretum you can call up your list of favorites and see where each one is on the map.

The map was originally created in 2014 as part of a grant from the Institute of Museum and Library Services. The map worked well on desktop computers, but was challenging to use on small smartphone screens. To improve the utility of the map for visitors actually in the Arboretum the Botanic Gardens contracted with SpatialDev, a local GIS development firm, to redesign the map to be responsive to handheld devices and to utilize the GPS location function built in to every smartphone. The redesign was partially funded by a gift from the Northwest Horticultural Society.

Want to try it? There is no app to install. Simply go to the Botanic Gardens website (uwbotanicgardens.org) and navigate to the Interactive Map under the Gardens tab.

If you want to use it again why not make a shortcut and add it to your home screen?

 

The map works on Android and Apple smartphones, tablets, and desktop computers


 

January 2016 Plant Profile: a Study on Sticks in the Witt Winter Garden

December 31st, 2015 by UWBG Communication Staff

Bare Naked in a Public Garden (a Study on Sticks in the Witt Winter Garden)

By Roy Farrow

photoI love January. The dark, wet, oppressive weather of December is past as the temperature finally drops consistently below freezing. Underfoot mud disappears overnight and we awake to glorious sunshine again. Our world seems expansive and encouraging.

I’ve come to understand that an important part of this feeling is due to the presence of “dormant” plants in the landscape. Dormant, or deciduous, plants allow the light from our very-low-on-the-horizon sun to penetrate our gardens and thus our inner beings. I qualify the word dormant because a walk through the Witt Winter Garden demonstrates that indeed it can be the leafless that are having the most fun this time of year.

As I walked through the garden this morning, my attention was torn between the just-beginning-to-crawl-out-of-their-buds witch hazels (Hamamelis sp.) and the pair of ruby-crowned kinglets gleaning from the mosaic of moss and lichen on the stems. As the birds flitted, about my eye was stolen by the multitude of buds of the winter hazel (Corylopsis sp.) and catkins of the giant filbert (Corylus maxima ‘Atropurpurea Superba’).

Magnolia stellata with frost

Quickly demanding my attention was the early winter diva Viburnum x bodnantense, of which there are three cultivars in the Witt Winter Garden: V. x bodnantense ‘Dawn’, ‘Deben’ and ‘Charles Lamont’. Other Viburnum such as V. farreri ‘Candidissimum’ and V. grandiflorum forma foetens (synonym V. foetens) will soon be following with their own fragrant display of naked gaiety. All other fragrances will eventually be forced aside by the aromatically dominant winter sweet (Chimonanthus praecox), now just a bird’s nest of sticks.

Corylus maxima 'Atropurpurea Superba'

Speaking of sticks, I often thank Miss Nature for populating our world with the many plants, particularly willows and dogwoods which are simply decorous without any adornment beyond their own skin. No one can enter the garden without their eye being caught by the midwinter fire dogwood (Cornus sanguinea ‘Midwinter Fire’). Once there, your eye may also appreciate the elegance of the bluestem willow, Salix irrorata with its white bloom and the bright golden-yellow of Salix alba ‘Vitellina’ behind it. Two newcomer willows to the Witt Winter Garden are Salix fargesii and Salix ‘Swizzle Stick’. The sleek, naked stems and large, red buds of Salix fargesii are difficult to describe without using the word “gorgeous” and the swizzle stick willow has an upright, contorted form which is colorfully impressive.

Salix 'Swizle Stick'

There are plenty more examples of naked fun to be enjoyed over the next few months, including the berries of Ilex verticillata ‘Red Sprite’, the playfully fuzzy buds of Magnolia stellata and the brief, but powerfully fragrant flowers of Abeliophyllum distichum. Last, but not least is the royal trifecta of stunning mature bark: Stewartia monadelpha, Betula albosinensis var. septentrionalis and Acer griseum. Please visit repeatedly as the Witt Winter Garden is quite dynamic and no two weeks will display the same show. Enjoy the cold!

Betula albosinensis var septentrionalis

Ilex verticillata 'Red Sprite'

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.

Glimpse into the past – Trees Have a Habit of Growing

December 17th, 2015 by Jessica Farmer, Adult Education Supervisor

By John A. Wott, Director Emeritus

It is said that humans “have a habit of growing.” We grow tall in our formative years, and most of us also grow wider in the later years. We could also say that trees have a habit of growing. Tree species grow to specific heights and widths. Some smaller trees obtain their normal mature size in a few years, while the larger species may grow for years and years. In fact some large forest trees may continue to grow for hundreds of years.

In our urban sites, native conifers are capable of continuing their growth for hundreds of years. Any time the temperatures are in the 40s or above (which happens just about every day of the year here), the chlorophyll molecules are busy manufacturing sugars.

When we visit a park on a regular basis, we are very unaware that the trees we see are growing larger every day. I remember someone once saying, “I visit the Arboretum every year, and the plants have not changed at all over the last 25 years.” Rubbish! The Arboretum changes daily due to this continuous tree growth. The conifers gradually grow larger and larger and suddenly, their size can “ambush” us. I am sure most of us have had the experience of suddenly realizing that the cute little evergreen we planted 20 years ago is now overpowering the house.

View of Section C, Nursery and Seedling beds

1. A view of Section C Nursery and the Seedling Beds where thousands of plants have been started. Fred Leissler, asst. dir. 1935- 37

This series of pictures shows such a progression of growth. The first picture above, taken by Fred Leissler, Assistant Park Director in 1935, shows seedling trees of western hemlock (Tsuga heterophylla)  planted along Section C of the Nursery and Seedling Beds as a screen and windbreak. The picture notes indicate that thousands of plants had been started there in those sunny beds. Note that Arboretum Drive E. is a wide lane.

Pictures 2 and 3, below, show the same trees on January 15, 1950, just 15 years later, and already making a sizeable screen.

46b. Hedge of Western Hemlock, 30 ft., A. macrophyllym, 1-15-1950

Hedge of Western Hemlock (Tsuga heterophylla) outside nursery. Trees of Oregon maple (Acer macrophyllum) on left. January 15, 1950. By E.F. Marton, UW

 

Hedge of Western Hemlock (Tsuga heterophylla) outside nursery. Tallest specimen about 30 ft. January 15, 1950. By E. F. Marton, UW.

Hedge of Western Hemlock (Tsuga heterophylla) outside nursery. Tallest specimen about 30 ft. January 15, 1950. By E. F. Marton, UW.

Along Arboretum Drive, other species of conifers were planted in rows during this time and into the late 1950s. These were mostly native species, such as the Western redcedars (Thuja plicata) in pictures 4 and 5 below.

4. Hedge row of Leyland cypress, December 14, 2015

4. Hedge row of Western redcedar (Thuja plicata), December 14, 2015

 

46e 0151214_141442

5. Hedge row of Western redcedar (Thuja plicata), December 14, 2015

However, one of the final plantings of this type were of the newly introduced Leyland cypress (× Cuprocyparis leylandii), which is a cross between the Monterey Cypress (Cupressus macrocarpa) and the Alaska yellow cedar (Xanthocyparis nootkatensis). These were sent to us from Hillier Nurseries in England via the Institute of Forest Genetics in Placerville, CA. They were planted at the north end of Arboretum Drive E., just to the west of the Greenhouses (and current Plant Donations area).

These trees, while extremely fast growing, have proved to be inferior landscape trees. They have weak, soft wood, and are prone to wind damage. They are best used as a tall sheared hedge and kept under 20 feet. Our trees were planted out in the late 1950s and grew rapidly. One large specimen, shown below in picture 6, toppled on December 10, 2015, probably due to root removal by the lowering of Arboretum Drive for the construction of the Graham Visitors Center in 1985 (west side), and the recent heavy rains. This is an excellent pictorial example of continuous tree growth and how conifers grow and grow and grow. It is also an example of the need for continual evaluation and management of trees and their appropriate placement in the landscape.

6. Toppled Leyland cypress, December 10, 2015

6. Toppled Leyland cypress, December 10, 2015

 

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’?

December 2015 Plant Profile: Euonymus europaeus ‘Atrorubens’

November 26th, 2015 by Catherine Nelson, Adult Tours Program Assistant

euonymuseuropaensatrorubenseuonymuseuropaeus

Found in its native Europe, Euonymus europaeus ‘Atrorubens’, or spindle tree, is commonly seen as an understory shrub or small tree growing along deciduous woodland edges. Quite shade tolerant, it loves calcareous, well-drained base-rich soils and can grow up to 20’ tall. It is considered cold and drought tolerant. While labeled as invasive in some areas of the Northeast, it seems to behave itself here in the Pacific Northwest; the specimens in our collection have been here since the late 1940s and maintain their size at about 10’ x 6’. The easiest specimens to locate in the Washington Park Arboretum are in the Pinetum, tucked in between the cedars and the Coulter pines. You can’t miss them this time of year.

Traditionally, this plant’s stems were used to make spindles to twine wool and flax into yarn. It contains many medicinal properties in its roots and bark which were used by both Europeans and the Iroquois in Northeast America and Canada, where it spread widely after introduction to the new continent. While the fruits are eaten by a variety of animals in the plant’s native habitats, they are poisonous to humans.

The spindle tree is currently used as an ornamental garden feature, and the cultivar ‘Red Cascade’ has won the Royal Horticultural Society’s Award of Garden Merit. While its late spring flowers (small yellow cymes) are considered inconspicuous, its amazing orange fruits and pink sepals are brilliant in the fall and will persist into deep winter on the shrub. The ‘Atrorubens’ cultivar is prized for its bright red fall foliage, similar to its cousin the “burning bush” euonymus.

Common Name: Spindle Tree

Family: Celastraceae

Family Common Name: Bittersweet Family

Locations:
Washington Park Arboretum

  • Pinetum (555-42*B & D in 38-5W)
  • Pacific Connections Garden (555-42*A in 6-1E)

Origin: Northern Europe and UK

Height and Spread: to 20’ tall x 10’ wide

Bloom Time: late spring

Glimpse into the past – a Surplus of Cedar

November 24th, 2015 by Jessica Farmer, Adult Education Supervisor
1937, splitting cedar fence uprights

1937, WPA splitting cedar fence uprights

By John A. Wott, Director Emeritus

One of the four primary forest trees of the Pacific Northwest is Thuja plicata, or the Western red cedar. There are “giants” of this species still growing after hundreds of years in protected sites in this state, but most were logged in great quantities as the lumber mills in the Pacific Northwest grew. The Washington Park Arboretum land, originally owned by the Pope Lumber company, was logged in the late 1880s and then basically clear cut of any remaining harvestable trees a few years later. Realizing that the city was growing up the hill, Pope sold the “developable” property and gave the drainage valley (now known as Arboretum Creek) to the City as open space in exchange for utilities which are all contained in the famed “Wilcox Bridge” over Lake Washington Boulevard East.

1937, WPA setting fence posts

1937, WPA setting fence posts

The red cedar produces many seeds and thus seedlings, and is an early invader of forest lands. It can germinate and grow under the dense shade of the big leaf maple (Acer macrophyllum). Since these trees are evergreen with many needles full of chlorophyll, they can photosynthesize every day of the year. They grow rapidly and tall. In the early part of the last century, Western red cedar seedlings flourished and produced many young trees in the fledgling Arboretum.

1937, WPA sawing cedar logs

1937, WPA sawing cedar logs

The University of Washington Arboretum (its original name) officially began in 1934. These were depression times, and there was little money to develop any of the ideas in the Dawson Plan which had been accepted. However, federal funds obtained through the State brought hundreds of men to work here through the Works Progress Administration (WPA) and Civilian Conservation Corps (CCC). Even though fences around the Arboretum have been a subject of controversy, there seems to have always been some type of fence along the eastern side, bordering Broadmoor Golf Course.

1937, WPA puttingup fence uprights

1937, WPA putting up fence uprights

These photos from 1937 show men (often in their hats and reasonably dressy clothes) working through the WPA sawing, spitting and building a tall cedar fence. Since cedar is an extremely durable wood for use in northwest climates, the fence lasted for years as shown in a picture from 1951. Eventually it deteriorated and has been replaced by a tall rather unsightly wire fence.

When an inventory of the native matrix of trees was conducted in the 1990s, it was obvious that there was a ten year dearth of missing cedar trees, proving that the lumber for the fence was cut in the Arboretum. Another side bar is that many of the original drainage pipes were hollow cedar logs, some of which are still in use in the Arboretum. What a novel idea, using our own ecosystem for beauty as well as worth.

1951, from Sequoia to Deutzia, Phila.....note fence

1951, from Sequoia to Deutzia, Phila…..note fence

Introducing – Free First Thursday Tram Tours

November 23rd, 2015 by Jessica Farmer, Adult Education Supervisor
Photo by Cit-E-Car electric vehicles

Photo by Cit-E-Car electric vehicles

We are excited to announce the arrival of a new 13-passenger tram at the Washington Park Arboretum. This tram will allow visitors with limited mobility to explore more of the Arboretum, and will offer all riders the chance to travel from the Graham Visitors Center to the Pacific Connections Garden (and other south-end collections) in less time and with more comfort! With the arrival of the tram, we are piloting free tours on the first Thursday of each month, starting in December 2015 and running through March 2016. The tram is open-air and does not have a heater, so riders will want to bundle up!

**UPDATE 2/4/16: We will be continuing the First Thursday Tram Tours throughout 2016, and likely beyond. Check our events calendar for upcoming dates and to register.

What: Free First Thursday Tram Tours

When: 11:00am – 12:00pm on the first Thursday of each month

Where: Meet at the Graham Visitors Center, Washington Park Arboretum, 2300 Arboretum Drive E, Seattle, WA 98112

Why: Sit back and enjoy the ride! Learn about our seasonal highlights, new plantings, Arboretum history and educational programs.

How: Register through our public class registration page. Space is limited to 13 participants per tour.
Your registration helps us plan for the space. Please only register if you will be here. Registration will be open until 8:30am the morning of the tour.

In addition to our previously offered walking tours, groups may now choose to schedule a private tour on the tram. All tours are led by knowledgeable tour guides, and pricing is based on the size of the group. Learn more about booking a private tour for your group.