Core Collection Highlight: Viburnum

April 5th, 2015 by UWBG Horticulturist
Selected cuttings from the Viburnum Collection at the Washington Park Arboretum (3/30/15-4/13/15)

Selected cuttings from the Viburnum Collection at the Washington Park Arboretum (3/30/15 – 4/13/15)

Our Viburnum Collection is recognized as one of the top three national collections. Our taxonomic display currently is home to over 100 different kinds and 330 living specimens.
[Description references: “Viburnums — Shrubs for Every Season” by Michael Dirr.]
Here are a few samples of this diverse and ornamental shrub.

1)  Viburnum carlesii var. bitchiuense        Bitchu Viburnum

  • Wonderfully fragrant flowers in early spring.
  • Closely allied to V. carlesii.  Botanists still debate whether to “split” or “lump”.
  • Located across from the Graham Visitor Center in full flower. Grid: 40-3E

2)  Viburnum macrocephalum       Chinese Snowball Viburnum

  • 6’-10’ rounded shrub.
  • Known for 3″ – 8″ wide, hemispherical cymes, hence the name “Snowball”.
  • Located along maintenance facility mixed-shrub border fence. Grid: 43-5E

3)  Viburnum propinquum

  • Large evergreen shrub with glossy three-veined leaves.
  • Known to be tender in cold Pacific Northwest winters.
  • Located in the Rhododendron Glen parking lot landscape. Grid: 12-8E

4)  Viburnum x rhytidophylloides ‘Alleghany’        Lantanaphyllum Viburnum

  • National Arboretum introduction in 1958.
  • Handsome dense evergreen shrub with abundant inflorescences.
  • Located in Viburnum Collection. Grid: 25-5W

5)  Viburnum utile        Service Viburnum

  • Rare in commerce, but important evergreen species for breeding.
  • Dirr doesn’t think it has much ornamental value. I (David Zuckerman) disagree.
  • Located in Viburnum Collection. Grid: 26-4W

Exploding trees, now showing at your local Arboretum

April 1st, 2015 by Kathleen DeMaria, Arboretum Gardener

March did not go out like a lamb, nor did it end with a whimper. No, this lion ended with a grand BANG!

A lightning strike from the massive thunderstorm that roared through Seattle yesterday was a direct hit on one of our largest trees in the Washington Park Arboretum.

Lighting strike as seen from the Columbia Tower. Photo courtesy of KOMO

Lighting strike as seen from a helicopter and from the Columbia Tower. Photos courtesy of KOMO

 

A Grand Fir located in the Oak grove at the north end of the Arboretum was obliterated with one flash. All that remains of a tree that was easily over 100 feet tall is a jagged snag and a circular field of debris extending at least 150 feet in all directions.

Lightning Strike 3.31.15 002

 

Electricity always takes the path of least resistance, so arborists in places where lightning is common will install tree protection systems. These usually are metal rods affixed to the top of the tree with a metal cable running down the tree to a ground rod buried deep in the soil. This system allows the tree to avoid catastrophic explosions like the one we had yesterday. Lightning is relatively uncommon in the Seattle area, so none of our trees have lightning protection systems.

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So why did the tree explode instead of just breaking or cracking? Good question. A lightning bolt is hotter than the surface of the sun and has a strong electric current. The current is carried through the tree by the sapwood below the bark. This sapwood is composed of mostly water and when the bolt’s heat and electrical charge hit the tree, the water boils instantly and turns to steam; just like a pressure cooker, except the tree doesn’t have a steam release valve on top. So the result of the excessive heat and  pressure causes the tree to explode. This is not common, but the results are spectacular!

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We will never know why this tree was hit, but we have had a day full of speculation and mitigating safety hazards. Was the lightning attracted to this metal bolt inside the tree from a former cable?

Lightning Strike 3.31.15 020

Was it just a case of being in the wrong place at the wrong time? Was it the high volume of spring sap running? Was it because it was the tallest tree in an open area near water? Was it all of these factors and some unknown? We may never know but we will never forget.

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One odd bonus of this amazing event is that lightning strikes are one of a few (non-synthetic) ways to fix nitrogen in the soil. Along with nitrogen-fixing bacteria and algae, the heat of a lightning flash causes atmospheric nitrogen to combine with oxygen to form nitrogen oxides. These oxides then combine with atmospheric moisture and are then delivered to the soil by rain, where it is transformed by microorganisms into nitrates that can be taken up by plant roots. Fascinating.

We know you never need an excuse to visit the Washington Park Arboretum, but we plan to keep the debris field intact for a few more days so any curious onlookers can come and check out our exploding tree. For your own safety, please stay behind the barriers, and enjoy the show.

 

 

 

Glimpse into the Past – Thirty Years of Horticultural Outreach

March 31st, 2015 by UWBG Communication Staff

By John A. Wott, Director Emeritus.

When the Center for Urban Horticulture was established in the early 1980s, one of the programmatic goals was to create and carry out a comprehensive public outreach program into the community for gardeners and professionals. The University of Washington is not part of the federal land grant system and thus receives no federal or state monies for such programs, as is the case for Washington State University. Thus any resources and programs developed had to be self-supporting.

Private funds were found to assemble the buildings on the UW East campus, which were built from 1984-1987. The addition of the Graham Visitors Center in 1986 at the Washington Park Arboretum added an additional site for Arboretum focused programs.  As programs grew, so did the staff to support them.  In the late 1980s and 1990s,  the annual total number of participants in classes, facility inquiry visits, tours, school programs, telephone inquiries, public open houses, library visits, as well as community lectures and tours at both the Center for Urban Horticulture and Washington Park Arboretum reached into the thousands.

The addition of Washington State Master Gardening clinics, classes and lectures greatly expanded both community gardening and professional landscape and nursery programs.  The school programs increased at the Washington Park Arboretum. Both programs became year round.  In the 1990’s, we often boasted that we were “second” in UW community outreach numbers, although quite some distance behind the UW Athletic events.

Since the beginning and continuing today, these programs have been lead by a talented group of staff.   Many people have started their careers with us and then gone onto “greener pastures,” making their mark throughout the country.

staff photo

Early outreach staff at the Center for Urban Horticulture in 1992: Jean Robins – Office Coordinator and Administrator; Larry Vickerman – graduate student and Class Coordinator; Dave Stockdale – Outreach Coordinator; Lynda Ransley – GVC Manager and Washington Park Arboretum Program Leader; Fran (Trinder) Myer – Budget and Fiscal Analyst; Rebecca Johnson – Building Rental Coordinator

In thirty years, there have been changes in the horticulture outreach environment:  public budgets have decreased; there is now a plethora of gardening information on the internet; and there is increasing emphasis on environmental, conservation, and restoration issues.  The baby boomer generation is retiring and today’s consumers have less interest in large gardens although they are more food and environmentally conscious.

Annual reports of specific numbers and program themes are archived in both the Miller Library and UW Archives.  The included photos are one glimpse of the continuing education and outreach staff  taken in December 1992.

staff photo

Early staff for Center for Urban Horticulture outreach program in 1992: Jean Robins – Office Coordinator and Administrator; Larry Vickerman – grad student and Class Coordinator; Professor John Wott, Faculty Supervisor; Lynda Ransley – GVC Manager and Washington Park Arboretum Program Leader; Fran (Trinder) Myer – Budget and Fiscal Analyst; Rebecca Johnson – Building Rental Coordinator.

Getting Low On Plants? Our Plant Sale Calendar Will Help!

March 30th, 2015 by Tech Librarian, Tracy Mehlin

Believe it or not, there are over 100 plant sales in the Pacific Northwest in April. Find rare dahlias or fuchsias at specialty sales or tried and true annuals and perennials at general sales. The Elisabeth C. Miller Library compiles a list of regional plant sales and garden tours so when you get tired of weeding, consult the calendar and go buy plants instead!

A few of our favorite sales:

  • FlorAbundance at Warren G. Magnuson Park, Building 30, Saturday, April 25, 9 am to 5 pm Sunday, April 26, 10 am to 2 pm; Benefits the Washington Park Arboretum
  • Master Gardener Foundation Plant Sale at the Center for Urban Horticulture, Saturday,  May 2,  9 am to 5 pm and Sunday, May 3, 11 am to 3 pm
  • Hardy Fern Foundation’s Fern Festival 2015, Center for Urban Horticulture, Friday, June 5, noon to 6:30 pm and Saturday June 6, 9 am to 2 pm
photo

Shop for rare plants and support a good cause at the Florabundance Plant Sale! Photo courtesy of Arboretum Foundation.

Encouraging Native Pollinators at the UW Farm

March 27th, 2015 by Jenelle Clark

University of Washington graduate student Nicolette Neumann Levi is looking for ways to bring more native pollinators to the UW Farm. Nicolette recently obtained a $1,000 UW Campus Sustainability Fund (UWCSF) grant to help support the installation of several new native pollinator plantings at the UW Farm, Center for Urban Horticulture site. Nicolette is embarking on this endeavor as part of her thesis project as a candidate for the Master of Environmental Horticulture degree. Her funding will support the installation of a herbaceous perennial garden with plantings specifically chosen to attract native pollinators, as well as a pollinator hedge that will further provide food and habitat for beneficial pollinator insects.

Nicolette_1

Recently Nicolette had the opportunity to meet with UWBG curation staff and horticulturists to discuss plant choices, especially options that would be easy to grow and maintain while providing the most benefit to the pollinators. Some of the preliminary plant ideas include grasses, violets, trilliums, sunflowers, and irises for the herbaceous perennial gardens, and evergreen huckleberry and grasses for the hedgerow. The concept is to use all local, native plantings in these gardens to lower maintenance needs and avoid the requirement to directly irrigate.

Work on the project will start this spring with the preparation and planting of two patches at the north end of the farm for perennial flowers. Over the summer, Nicolette also plans to install plastic film to solarize the areas at the southern edge of the farm where the pollinator hedge is slated to be planted. This will utilize passive solar heat to remove pests and pathogens prior to planting.

Working with Native Pollinators

By planting exclusively native plants, Nicolette hopes to attract a wide variety of the native pollinators found in the Seattle area. “The idea is to use native plants to attract what would naturally be around the [local] area.” she explains. Some of the local pollinators she is hoping to see more of at the Farm include honey bees, orchard mason bees, butterflies, and hummingbirds. While each of these pollinators have specific native plants that they prefer, Nicolette is utilizing a diverse palette of plants with blooming times staggered throughout the growing season to try to consistently attract as many pollinators as possible. “Overall it’s healthier to have a more diverse mix of insect,” she explains.

Nicolette is hoping that by bringing in a diverse mix of pollinators it will have measurable impacts on the Farm’s overall crop yield too. She will be measuring this impact as a part of her thesis work, as well as continuing to do frequent pollinator counts to see if her efforts are making a difference. Nicolette does have high hopes for the impact the perennial gardens and pollinator hedge will have on the UW Farm:

“Many farms will have to bring in on a yearly basis a box of bees. By trying to attract the native pollinators you don’t have to do that and spend all that money every year. You can maintain the populations and have a place for them to overwinter. It saves money.”

Not only will the plants in the garden and hedge provide pollen for the pollinators, they will also be chosen to support these beneficial insects in their various life-stages (i.e. larval, such as a caterpillar) and provide food, habitat, shelter, and hiding for adults. The hope is that these new plantings will also provide over-wintering habitat for the pollinators so that the Farm can start to grow a larger base population of pollinators right where they need them

A Network of Green Spaces

One of the challenges facing pollinators today, especially in urban areas like Seattle, is habitat fragmentation and the loss of green spaces. An exciting possible benefit of this project is its ability to provide a vital patch of habitat, for many types of pollinators, right in the heart of the University District. “The flight range or movement [for pollinators] between different patches is not so big, so you end up with these isolated patches,” Nicolette explains. “You miss out on the opportunity to have pollinators moving through a mosaic of habitat patches. Having one more pollinator garden adds one more place for the population to move to and grow”.

Pollinator Garden

National groups such as the Pollinator Pathway and the Xerces Society are working to bring awareness to the importance of habitat patches and are focused on promoting more urban gardens with plantings tailored towards the needs of native pollinators. Home gardeners can get involved too and help to provide vital habitat patches by fine-tuning their own growing spaces to meet the needs of more pollinators. Nicolette recommends that home gardeners, “try to use plants that would naturally be growing [in our region] and blooms that are in a variety of colors.” She also encourages, “using plants that bloom at different times during the growing season,” to consistently attract pollinators throughout the season. Bee boxes, such as those made for mason bees, could be something a home gardener could use.

The most important thing is to make sure that the plants chosen match up well with the needs of our local pollinators. Starting with native plants is a good place to begin, but Nicolette also recommends checking with your local nursery or gardening outreach program (like the Center for Urban Horticulture) to get more ideas and guidance with setting up your own pollinator garden.

The Elisabeth C. Miller Library has a list of recommended books on Pollinators and Pollination.

Weekend Family Fun!

March 26th, 2015 by Sasha McGuire, Education Program Assistant

Get outside and explore the Botanic Gardens by day or by night with these new family-friendly hikes.

Park in the Dark

Night Hike ImageNight time is special at the Arboretum – the people and cars are gone, and the nocturnal animals move about. Night hikes are a chance for us to explore our senses, search for crepuscular and nocturnal movements in the forest and learn about night-related animal adaptations. Programs are designed for families with children aged 5-12 and run from 7:30-9pm on the 2nd Saturday of the month. Meet at the Graham Visitors Center!
Cost is $8/person
Register online or call 206-685-8033

Dates (all programs are from 7:30-9pm)

  • April 11th
  • May 9th
  • June 13th

birdkids

Family Nature Walks

Family Nature Walks focus on discovering the wonders of nature through fun and engaging activities, games, and exploration. Search for mushrooms, pretend to be a pollinator, or spot birds using binoculars!  This class is best suited for families with children ages 5-12. Walks will continue rain or shine (hopefully shine!) – dress for the weather and wear comfortable shoes that can get wet or dirty. The walks start at 10:30, the 3rd Saturday of the month and are 90 minutes long. Meet at the Graham Visitors Center!

Cost: $7/person (kids 3 and under are free, so don’t count them toward your payment)
Register online or call 206-685-8033

Themes (all programs are from 10:30am-12pm)

March Color Appears at the Washington Park Arboretum, Part II

March 23rd, 2015 by UWBG Arborist, Chris Watson
Selected cuttings from the Washington Park Arboretum (March 16-30, 3015)

Selected cuttings from the Washington Park Arboretum (March 16 – 30, 3015)

1)  Acer tegmentosum  ‘Joe Witt’        Stripebark Maple

  • A small- to medium-size tree with distinct striped patterns along the bark and branches
  • Named for a former Washington Park Arboretum curator
  • Located in the Joe Witt Winter Garden

2)  Berberis x media  ‘Arthur Menzies’        Hybrid Mahonia

  • Multi-stemmed shrub with prominent winter flowers
  • Loved by hummingbirds as a source of winter nectar
  • Located in the Joe Witt Winter Garden

3)  Ceanothus  ‘Puget Blue’        California Lilac

  • A fast growing, medium-sized shrub
  • Known for small dark, evergreen leaves and purplish-blue late spring flower
  • Located along the fence in the Graham Visitors Center’s parking lot

4)  Magnolia x kewensis  ‘Wada’s Memory’        Hybrid Magnolia

  • Selected from a group of seedlings from nurseryman, Koichiro Wada
  • Known for large and abundant spring flowers
  • Two specimens flank Arboretum Drive near the Hydrangea Collection

5)  Nothofagus antarctica  ‘Puget Pillar’        Southern Beech

  • A medium-sized deciduous tree native to Argentina and Chile
  • Known for a somewhat fastigiate growth habit
  • Located along the shore near Duck Bay

April 2015 Plant Profile: Anemone nemorosa ‘Viridiflora’

March 23rd, 2015 by Soest Gardener, Riz Reyes

Anemone nemorosa 'Viridiflora' Wood Anemones are wonderful, easy to grow, spring ephemerals that require patience to get established, but once they get going, they form wonderful clumps in moist woodland conditions. What makes them sought after by gardeners is their ability to thrive in dry shade underneath mature trees. They have delicate fern-like foliage which set off the drifts of flowers that light up the spring landscape!

A. nemorosa flowers come in shades of blue, white, pink, with singles, doubles, and this most unusual form. This species has a remarkable tendency to mutate and the cultivar selection ‘Viridiflora’ (“green flower”) is a great example! What typically would be petals are actually modified leaves know as bracts. This creates an unusual moss-like texture and it’s absolutely charming combined with all the other plants in the garden as they burst into growth in spring. As with all wood anemones, they will begin to naturally die down in late spring and will rest until the following spring so be sure to mark where they are planted.

Anemone nemorosa 'Viridiflora'

Family: RANUNCULACEAE
Genus species ‘Cultivar': Anemone nemorosa ‘Viridiflora’
Common Name: Green flowered Wood Anemone
Location: CUH Soest Garden – Bed 7
Origin: Native to Europe, but selection may be of Garden Origin
Height and Spread: 4-5″ height x 24″ width spread on mature, undisturbed plantings
Bloom/Fruit Time: March-April

 

Currently flowering in the Washington Park Arboretum

March 21st, 2015 by Catherine Nelson, Adult Tours Program Assistant

Chaenomelescathayensis

In the old Nursery along Arboretum Drive there is a group of Chaenomeles cathayensis (Cathay or Chinese Quince) shrubs in full bloom. This cluster of three shrubs make for a huge display as they are about 15 ft. tall and 20+ ft. across. Covered in these lovely pinkish white flowers right now, they will bear very fragrant pear sized fruits in the autumn.

Known in Chinese as Mu Gua, this plant is native to China, Bhutan, and Burma where the fruits are used in traditional medicine.

These fruits are not commonly used in cooking as their European Quince cousins are. They are quite sour and must be blanched and dried in order to process them for consumption. According to Purdue University’s New Crop Resource, they are valuable for the “high content of organic acids in the juice, distinctive aroma, and high amount of dietary fiber.”

 

Heath Family Highlights!

March 20th, 2015 by Sasha McGuire, Education Program Assistant
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Kalmia latifolia, a member of the heath family

Join Chris Pfeiffer to explore the UW Botanic Gardens collections this April. Spring brings flowers of course, and this 4 hour class has a focus on the blooms and habits of the Ericaceae – including rhodies, azaleas, and lesser known plants of the Heath family. You might also recognize blueberries, heather, madrona, and sourwood as belonging to this group.

In addition to identification, we will also look at bloom characteristics, foliage types, landscape functions, care and pruning tips for long-term healthy plants.

Professional credits include ISA, CPH, ecoPRO, ASCA and PLANET, though you don’t have to be a professional to register. Plant nerds and homeowners are welcome!

Learn about this diverse group of plants with instructor Chris Pfeiffer, a horticulture consultant, instructor and garden writer with over 30 years’ experience in landscape management and arboriculture. Sustainable and efficient landscape techniques are a special area of interest and expertise. In addition to her private practice, she is a consulting associate with Urban Forestry Services, Inc. and an active volunteer with local community garden projects. She previously led landscape management efforts for the Holden Arboretum and Washington Park Arboretum. A frequent horticultural speaker, Christina has taught courses in pruning, arboriculture, and landscape management at Edmonds and South Seattle Community Colleges, and at the University of Washington. She holds degrees in horticulture from Michigan State and the University of Washington and is an ISA Certified Arborist. She is co-author with Mary Robson of Month-by-Month Gardening in Washington & Oregon (Cool Springs Press 2006).

Class information:

What: Arboretum Plant Study: Seasonal Plant ID and Culture – Spring Session

When: Thursday, April 30th, 8am-12pm

Who: Landscape professionals, homeowners, gardeners, plant enthusiasts

Where: UW Botanic Gardens – Washington Park Arboretum (2300 Arboretum Dr E, Seattle)

Cost: $65; increases to $75 one week before the class

Register: Online, or by phone (206-685-8033)

 

Picture courtesy Stephanie Colony

Picture courtesy Stephanie Colony