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

September 28th, 2014 by UWBG Horticulturist
Selected cuttings from the Washington Park Arboretum (September 22 - October 6, 2014)

Selected cuttings from the Washington Park Arboretum (September 22 – October 6, 2014)

1)    Alnus glutinosa ssp. betuloides
Birch-leaved Alder

  • Native to the mountains of eastern Turkey.
  • Listed as a threatened species by the International Union for Conservation of Nature.
  • Autumn brings pendulous male catkins and the mature female cones.

 

2)   Catalpa x erubescens        Indian Bean Tree

  • Uncommon tree with fetching, large, chocolate-purple young leaves that turn green.
  • Late summer brings masses of creamy white flowers flecked with yellow.
  • Hanging seed pods appear and remain long after the leaves have dropped.

3)   Pterocarya rhoifolia        Japanese Wingnut

  • The Wingnuts belong to the Walnut (Juglandaceae) family.
  • The amount of edible nut is comparable to that of the Scots Pine, i.e. not much.
  • The hanging decorative catkins give the tree a distinctive appearance in late summer.

4)   Styrax obassia        Fragrant Snowbell

  • This tree produces 6-8 inch fragrant white bell shaped flowers May to June.
  • Native to Hokkaido Island of Japan.
  • The tiny green seed pods hang like ornaments well into late summer/fall.

5)   X Sycoparrotia semidecidua        Chinese Fig Hazel

  • An inter-generic cross between two species – Parrotia persica and Sycopsis sinensis.
  • The flowers are unique, inconspicuous and easy to overlook.
  • The seed pods are beautiful ocher-colored, three dimensional stars.
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Washington Park Arboretum Soil is More Than Dirt

September 26th, 2014 by Kathleen DeMaria, Arboretum Gardener

This past April the Camellia area of the Washington Park Arboretum was paid a scientific visit by UW SEFS professor Dr. Darlene Zabowski and students from her Advanced Soil Genesis and Classification course (SEFS 513). Their goal was to learn how to excavate a soil pit and mine the walls for information about the history of the site, the current state of the soil and potential issues that may need mitigation. The site was chosen by David Zuckerman, Supervisor of Horticulture, as our Camellia collection is in need of a renovation, and he’s a strong proponent of soil analysis prior to any work being done in an area.

As with any good assessment, photos of the site were taken prior to any disturbance:

Camellias before dig

 

This site is located in the south end of the Arboretum just north of the gravel path leading to the newly refurbished lookout in the New Zealand garden. After the leaf litter and duff were cleared, the students started digging, and digging until a 3 foot deep pit was completed (notice the clear separation of ‘horizons’, or layers of soil):

Soil Pit2

In this area 3 feet was needed to ensure that the students got down to the ‘parent material’, or the underlying geological material in which soil horizons form. Soils inherit structure and minerals from their parent material through processes of physical or chemical weathering. This parent material remains the basis of the soil structure as other factors contribute to the soil’s texture (e.g. compaction, amendments, tillage).  According to Dr. Zabowski and her students, our Camellia soil has a parent material in the ‘Alderwood series’, and it shows evidence of compaction and large quantities of amended materials in the upper horizon. There was charcoal found in the middle/upper horizons indicative of a fire in the area (perhaps post-logging) or the charcoal could have come in with amendments added to the soil years ago. The parent material is glacial, composed mostly of ablation till and basal till and the years of amending and alteration can be seen even down into these lower horizons.

Soils layed out

As each horizon was unearthed, Dr. Zabowski (pictured above) had her students lay out a sample of the soil in ascending order to show and feel the difference from one layer to the next. The students were then charged with the task of coding out these samples by color using Munsell Soil Color Charts flip book. Soil color indicates the makeup of the soil within a given geographic area, which can influence the land’s fitness for usage. Samples of each horizon were also brought back to the lab and analyzed for chemical composition, bulk density, base saturation, and Cation exchange capacity (CEC). The Camellia soil was found to have a pH in the slightly acidic region (5.7-6.3), which is good for Camellias, as they like slightly acidic soil. The upper horizons of the soil were found to contain high levels of Ca, suggesting that there had been some CaCO3 added to the soil in the past (the high pH was also indicative of amending with CaCO3). The CEC of the soil was very high in the upper horizons, but this was to be expected at CEC is a measure of the soil’s fertility and nutrient retention capacity and this soil had been amended with organic matter for decades before this assessment (organic matter can have up to 3x the CEC of clay). The bulk density of the soil in the upper horizons suggests that there has been some compaction (likely due to foot traffic as there is a bench near the site) and that remediation of this density should accompany any work done in this area.

The UWBG horticulture staff welcomes and encourages university use of the arboretum for educational purposes as we curate and maintain 230 acres of urban forest as short walk from main campus. Got an idea for research in the arboretum? Contact David Zuckerman at dzman@uw.edu to get your shovels into our soil!

 


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Fruits & Nuts appear in autumn

September 23rd, 2014 by Catherine Nelson, Adult Tours Program Assistant

Read the rest of this entry »

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September Color Appears at the Washington Park Arboretum

September 14th, 2014 by UWBG Horticulturist


The State of the Arboretum

Selected cuttings from the Washington Park Arboretum (September 8 - 21, 2014)

Selected cuttings from the Washington Park Arboretum (September 8 – 21, 2014)

1)   Liriodendron tulipifera        Tulip Tree

  • The state tree of Indiana.
  • The Western Hemisphere representative of the two-species genus Liriodendron, and the tallest eastern hardwood.

2)   Pinus resinosa                 Red Pine

  • The state tree of Minnesota.
  • It is a long-lived tree, reaching a maximum age of about 500 years.
  • The wood is commercially valuable in forestry for timber and paper pulp, and the tree is also used for landscaping.

3)   Pinus strobus        Eastern White Pine

  • The state tree of Michigan.
  • Eastern white pine forests originally covered much of northeastern North America. Only one percent of the old-growth forests remain after the extensive logging operations that existed from the 18th century into the early 20th century.
  • This tree is known to the Native American Haudenosaunee (Iroquois Nation) as the “Tree of Peace”.

4)   Sequoia sempervirens        Coast Redwood

  • The state tree of California.
  • These trees are among the oldest living things on Earth.
  • Before commercial logging and clearing began by the 1850s, this massive tree occurred along much of coastal California and the southwestern corner of coastal Oregon.

5)   Tsuga hetrophylla        Western Hemlock

  • The state tree of Washington.
  • Tsuga heterophylla is an integral component of Pacific Northwest forests west of the Coast Ranges, where it is a climax species. It is also an important timber tree throughout the region, along with many of its large coniferous associates.
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3 reasons to buy plants for a good cause

September 11th, 2014 by UWBG Communication Staff

Why should you buy plants in autumn?

  1. trees, shrubs and perennials planted in warm fall soil get eight months of consistent moisture to become established before summer drought hits.
  2. Growers often discount plants in fall so that they don’t have to overwinter so much inventory.
  3. Serious plantaholics need a content flow of novel plants to keep their gardens interesting.

How to support worthy causes? Buy plants at charitable plants sales such as the Northwest Horticultural Society’s sale on September 12 & 13 or the Arboretum Foundation sale on September 27.

Not in Seattle? There are charitable plant sales all over the Pacific Northwest. Do your part, go out and BUY MORE PLANTS!

FallAbundance-logo-orange1

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Construction starting on “West Approach” to SR 520 Bridge will impact access to Arboretum

September 11th, 2014 by UWBG Communication Staff

YDrequfkThe Washington State Department of Transportation has announced the start of the next phase of the SR 520 Bridge replacement project. The West Approach Bridge North Project (WABN) will begin this month with the installation of construction fencing and preparation of staging areas. Construction will impact Lake Washington Bldv at the north end of the Arboretum and nearby residential areas. Construction update with map & project overview.

 

 

How to keep informed about the project:

Email
Sign up for WABN construction email updates:
public.govdelivery.com/accounts/WADOT/subscriber/new
Email project staff: SR520Bridge@wsdot.wa.gov
Online
Visit the SR 520 Orange Page website: www.wsdot.wa.gov/Projects/SR520Bridge/520orangepage/
Visit the WABN project website: www.wsdot.wa.gov/Projects/SR520Bridge/WABN/
Follow us on Twitter: @WSDOT_520
Phone
Call the SR 520 24-hour construction hotline: 206-708-4657

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Grand Cajun Yesler Swamp Ribbon-Cutting Celebration!

September 9th, 2014 by UWBG Communication Staff

AugustThirtyFirst-47-300x200The Friends of Yesler Swamp have been working for years to turn a weed choked corner of the Center for Urban Horticulture into a safe, accessible, natural area that supports wildlife.

On Sunday, September 21, 2014, 2 – 4pm they will host a public event to celebrate recent progress building a boardwalk.

Help us celebrate completion of the first phase of boardwalk construction through Yesler Swamp.

The Cajun band Folichon will be playing. We’ll have food, beer and wine plus tours of the swamp. Everyone is invited–all ages welcome. We will have a short program to thank the many organizations and friends whose generosity has made the Yesler Swamp Trail possible. Donations will be accepted to help finish the Trail. Free!

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Art Exhibit: Botanical art & hand-painted silks by Linda Ann Vorobik

September 8th, 2014 by UWBG Communication Staff

Vorobik paintingPaintings of ferns, orchids, and other treasures will be on exhibit in the Miller Library from September 19 to November 3rd. Botanists, teacher and artist, Linda Ann Vorobik, paints exquisite and botanically accurate water colors of ferns and orchids that will delight you.

Meet the artist at a free reception at the Library on Friday, September 19th from 5:00 to 7:00pm.

Feel inspired? Take a workshop from Linda on October 4th & 5th.

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September 2014 Plant Profile: Coreopsis Big Bang™ ‘Star Cluster’

September 4th, 2014 by Soest Gardener, Riz Reyes

Coreopsis Big Bang 'Star Cluster'Tickseed is the common name for the cheery and colorful Coreopsis. Long  utilized as a border plant in  perennial gardens, it’s often only know for its ferny green foliage and one main flush of bright yellow blooms in early summer. Now, thanks to Darrell Probst’s spectacular  breeding work on the Big Bang series, the genus has been revolutionized, with a wider range of colors with almost continuous bloom throughout the season! Skagit Gardens in Mt. Vernon, WA has sent us samples over the years to display and trial here at UW Botanic Gardens and we have them peppered around the Center for Urban Horticulture.

This stunning selection is ‘Star Cluster’. It probably has the tidiest habit of all the Coreopsis we have. It has worked very well as a edging plant because it stays fairly low and it has been in flower since June with minimal deadheading.  The color progression of the flowers is quite fascinating as it opens to a lovely cream with a crimson center and over time and as the weather cools for autumn, the center color softly blends and becomes more prominent on the entire flower.

 

 

Coreopsis Big Bang 'Star Cluster'

 

Coreopsis Big Bang 'Star Cluster' habit

 

Family: ASTERACEAE
Genus: Coreopsis
species: N/A
Common Name:  Tickseed
Location: Soest Garden Bed 5
Origin: Garden Origin.
Height and Spread: 15-18″ wide and 10-12″. tall
Bloom Time: June-Frost

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A glimpse into the past – origins of the Holmdahl Rockery

September 3rd, 2014 by UWBG Communication Staff

By John A. Wott, Director Emeritus

One of more famous locations in the Washington Park Arboretum is known as the Holmdahl Rockery, located along Lake Washington Boulevard E., and now the location of the Gateway to Chile Forest in the Pacific Connections Gardens section.

As cited in the Washington Park Historic Review, September 2003, page 78:

Otto Holmdahl was trained as a naval architect in Sweden, but became known as one of the best garden designers in the Northwest. Holmdahl consulted unofficially on the Arboretum for several years. He was well known to Sophie Krauss, who recommended that he be included in its planning: “I am sure some plan could be worked out for using some of the most competent men, such as Mr. Holmdahl who really does the most perfect rock gardens I think can be done…” In the summer of 1934, Holmdahl prepared a preliminary plan for the (entire) Arboretum, which was presented to the Advisory Committee. This plan has since been lost.

Frederick Leissler, Seattle Dept. of Parks Landscape Architect, had proposed the rock garden be located at the southwestern intersection of the Upper Road with Lake Washington Boulevard, where a steep hillside with southwest exposure provided better conditions for alpine plants. Leissler anticipated the rock garden would encompass 10 acres, but started the WPA (Works Progress Administration) crew in early 1937 laying basalt rock on the southernmost portion, and repairing the road cut made by the original construction of the boulevard. Otto Holmdahl supervised placement of stonework for the rock garden.

photo

Planting the Holmdahl Rockery. Click to enlarge.

Note the accession numbers jotted on to the photo to document the plantings. Click to enlarge.

Note the accession numbers jotted on to the photo to document the plantings. Click to enlarge.

Verbal legends passed by successive Arboretum staff indicated that several attempts were made to “populate” the rockery, but all met with ultimate failure, either due to the steep exposed terrain but mostly due to thievery of the small specialized plants. The photographs above, titled “Penstemon Plantings, 12 – 1954”, show an unidentified worker laying out specimens. A large number of accession numbers were added onto the photographs, and assumed planted. Needless to say, the penstemons also did not survive. Note the small sign pointing out the City of Seattle “Scenic Drive” on Arboretum Drive E.

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