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

 

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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.

“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/

 

 

2016 Family Nature Classes Open for Registration

November 18th, 2015 by Sasha McGuire, Education Program Assistant

Join us for a Family Nature Class and make connections with the natural world that will last a lifetime! Through science-based exploration and outdoor play preschoolers and their caregivers will experience the UW Botanic Gardens using their senses. We’ll explore sight, hearing, touch and smell, as well as delve into mud, trees, and what exactly happens in winter!

Here is what some previous families have said about Family Nature Class:

kids with binosI liked everything! I thought it was great how all the books and games during each class was specific to the topic of the class.”

“We all had a wonderful time. You had so many engaging activities for the kids and I liked how you had creative ways to incorporate the adults into the fun as well.”

“We really found the class inspiring and fun.”

Come see what all the fuss is about!

WHO: Children ages 2-8 and their caregivers.

WHEN: Thursday, Friday or Saturday from 9:30-11:30am  for 2-5 year olds
OR Fridays, 1-3pm, for 4-8 year olds.
WHERE: Washington Park Arboretum (2300 Arboretum Dr E, Seattle), under the white tent behind the greenhouse

SERIES: Sign up for 6 or more classes (any day of the week) $14/class for 1 adult and 1 child. Additional child: $7/class (children must be attending with the same adult to receive the second child discount). Additional adults are free!

INDIVIDUAL CLASSES: $18/class for 1 adult and 1 child. Additional child: $9/class (children must be attending with the same adult to receive the second child discount). Additional adults are free!

Register Online, or call 206-685-8033.

More information…

November Color Appears at the Washington Park Arboretum

November 11th, 2015 by UWBG Arborist, Chris Watson
Selected cuttings from the Washington Park Arboretum (November 2 - 15, 2015)

Selected cuttings from the Washington Park Arboretum
(November 2 – 15, 2015)

1)  Berberis fortunei             Fortune’s Mahonia

  • Native to China, this shrub sports deep-red new growth when grown in sunnier locations.
  • The mature size is 6-12 feet tall and just as wide.
  • This specimen is located in the Sino-Himalayan Collection (Grid 25-1W).

2)  Buxus wallichiana             Himalayan Boxwood

  • A large shrub or small tree native to the northwestern Himalaya and known for very dense, hard wood.
  • Trained as a small tree, our specimen is nearing its mature size at 10 feet.
  • This specimen is located in the Pinetum near the Wilcox Footbridge (Grid 39-4W).

3)  Illicum henryi             Henry Anise Tree

  • Native to China, this evergreen shrub has excellent, glossy foliage and small-but-noticeable red flowers that turn to unique star-shaped fruit in the fall.
  • This species is related to the plant from which the anise spice is derived.
  • This specimen is located along the Ridgetop Trail near the Magnolia and Asiatic Maple Collections (Grid 24-1W).

4)  Lithocarpus henryi             Henry’s Stone Oak

  • An evergreen tree native to China, the large, lance-shaped leaves give this tree a unique appearance.
  • This tree can reach heights of 60 feet in its native range.
  • This specimen is located along the service road, east of the Sino-Himalayan Collection (Grid 24-B).

5)  Stachyurus yunnanensis             Yunnan Stachyurus

  • The new growth of this Chinese shrub emerges pinkish-red and fades to green throughout the summer.
  • The new stems remain red until the following spring.
  • Located in the Sino-Himalayan Collection (Grid 25-1W)

Fiddleheads Forest School Fall Fair

November 5th, 2015 by Sarah Heller, Community Programs Coordinator & Fiddleheads Forest School Director

Walking with Parents through the woodsFiddleheads Forest School is hosting a Fall Fair at the Graham Visitor Center from 1-3pm on Nov. 14th!

Currently enrolled families and those interested in being a part of our Fiddleheads community are welcome to attend, rain or shine. The fair is family friendly and will feature:
-Fall Crafts
-Fiddleheads Science and Exploration Activities
-Hot Cedar Tea and Treats
-Forest Grove tours throughout the morning

Support our efforts and learn about: SPrOut (Study of Preschoolers Outdoors), a new research opportunity developed by Dr. Pooja Tandon of Seattle Children’s and the University of Washington in collaboration with Sarah Heller and Kit Harrington of Fiddleheads. Families enrolled or interested in Fiddleheads with preschool-age students will have the opportunity to participate this spring, 2016!

Fiddleheads is committed to developing evidence-based practice and encourages research efforts to better understand the benefits and impacts of outdoor learning and the Fiddleheads approach to education

Please share our event and help spread the word!

Fall Fair Flyer (image)Fall Fair Flyer