Fragrance Garden renovation enters phase two

December 3rd, 2014 by UWBG Communication Staff

The Fragrance Garden at the Center for Urban Horticulture is being refreshed with help from partner the Seattle Garden Club. The declining stripe bark maple will be removed and new scented plants will be added.

Fragrance Garden at CUH 11-2014Manager of Horticulture David Zuckerman said the Acer capillipes has been declining for years. David explained: “it may have verticillium wilt, but more likely to be causing the decline are symptoms of over exposure (sun, temps) during the course of its life in the entry garden. In general, stripe bark maples are forest edge trees, somewhat short lived and do not do well when grown in exposed conditions.”

A few of the new plants going in include:

  • Magnolia virginiana ‘Moonglow’
  • Itoh peonies
  • Berberis x media ‘Winter Sun’
  • Philadelphus ‘Belle Etoile’
  • Azara microphylla
  • Pieris japonica ‘Cavatine’
  • Chimonanthus praecox
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Arboretum Loop Trail nears construction start

November 5th, 2014 by UWBG Communication Staff

By Audrey Wennblom

An artist's rendering of one of the bridges on the Arboretum Loop Trail. Image courtesy the Berger Partnership

An artist’s rendering of one of the bridges on the Arboretum Loop Trail. Image courtesy the Berger Partnership

At long last, the Arboretum Loop Trail (ALT) appears to be just a few months away from the start of construction. “Right now, it looks like the tentative start date would be late spring 2015,” said Raymond J. Larson, Curator of Living Collections for the UW Botanic Gardens. “The idea is to start after most of the rain has passed and to do construction over the drier months.’’

Depending on the the bids received, Larson said the project may be done in two phases. The first phase would be from E. Madison Street to the Boyer/Birch parking lot along E. Lake Washington Blvd. (across from the Holly Collection), he said. The second phase, in 2016, would be from the Birch Lot to the Graham Visitors Center. Larson said, however, that it could also happen all at once. “It depends on a variety of factors,” he said, “and the contractor selected.”

But before any work begins, “the first thing we will do in the field is contract out the transplanting of collections,” said David Zuckerman, Horticulture Manager for the UWBG. “This work will begin as early as this fall sometime, even if it’s just root pruning,” he said.

The ALT is expected to have several benefits for the Arboretum.  “First, it will get people into areas of the arboretum that are currently less well known and visited,” Larson said.  Most people don’t make it to the viburnum collection or know where it is, and don’t get through the Flats (where birches, poplars and the creek is) much of the year because the ground is too wet and there are no trails there, Larson said.  “The ALT will also open up a new route through the largely undeveloped southern hillside across from the Japanese Garden and will provide another way to access the Pacific Connections Gardens,” said Larson.  That is an area currently difficult to navigate and where it is easy to get disoriented (especially for new or occasional visitors), Larson said. Access is going to be much better and the park should feel bigger, he said.

The collections themselves will also benefit. “We will have many new planting areas that will be accessible and viewable,” Larson said.  Some of these will anticipate future phases of the Pacific Connections China and Chile ecogeographic gardens.  “Where the trail crosses through these areas we will be planting plants from those areas along the way,” Larson said.  Other areas will see the addition of a diversity of new plantings that strengthen existing collections (viburnums, oaks, rhododendrons, etc.). “There are going to be a lot of new plants going in, and areas with a lot of ivy and invasives will be refreshed,” he said.

All of this adds up to a better visitor experience—finding your way more clearly as you navigate through the gardens. The north end will be enhanced with better sightlines and a clearer, more obvious connection to the Graham Visitors Center, where the trail forms a loop with Arboretum Drive E, Larson said.  It should feel less hidden and more welcoming.  Some existing blind spots will be improved and in general areas should feel refreshed.  “We think this will be a popular walking and bicycling trail, and the loop connection should help people better experience more of the park,” Larson said.

More Information

Seattle Department of Planning and Development trail project page

Seattle Parks and Recreation trail project page

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What to do with fallen leaves? Arborist Chris Watson considers the options

November 2nd, 2014 by UWBG Communication Staff
photo

Beautiful fallen leaves from the Amelanchiers growing at the Center for Urban Horticulture. Photo by Larry Howard 2007

To rake or not to rake? When asked what homeowners should do with leaves falling from trees growing in city gardens, Chris Watson, the Arborist who cares for the trees at the Washington Park Arboretum definitively stated, “It depends!”

Is the best mulch for a tree its own leaves? Or does that spread disease and pests? Chris explained:

“From a nutrient cycling perspective, ideally the leaves would be left in place where they fall.  Much like a forest, this would reduce the need for additional inputs, such as fertilizer. However, the urban situation is quite different from a forest.  We have introduced plants, soils, pests and diseases, as well as the desire for aesthetically pleasing landscapes.  Leaves blow in the wind and have the potential to clog drains.  Also, the first best management practice for most foliar diseases is to remove all leaves when they fall to reduce inoculum.

“When leaf removal is necessary, I recommend composting leaf material if possible.  The compost can then be used to amend soils around landscape plants.  If leaves are diseased, they should be composted in a way that increases the temperature to sterilize pathogens.  This is difficult to do for the typical homeowner, so it may be best to place leaves in the yard waste bin where they will be processed in a suitable manner.”

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Winter Garden Project: Remodeling the “Living Walls”

August 20th, 2014 by UWBG Horticulturist

Arboretum Tree Removal Notification:

 

The week of 8/25/14, UWBG tree crew will embark on a project located in the Winter Garden (read about project below). 

4 western red cedars will be removed due to negative impact to plant collections and garden encroachment. 

All pedestrian path detours and other safety considerations will be handled by tree crew. 

If possible, cedar logs will be salvaged for future park uses.  

UW professor of landscape architecture and designer of our Winter Garden (1987), Iain Robertson, states it’s time to open up the “room” that has been closing in on the Winter Garden for over 25 years. Continuous growth of the “living walls”, predominantly western red cedars, is now negatively impacting many of the garden’s choice plant collections. Due to this encroachment, the garden “room” is feeling confining. Judicious consideration and deliberation has led to the following curation and horticultural decisions.

Project Scope:

  • Removal of 4 western red cedars to provide needed light and future growing space for plant collections. In all cases, the “room’s walls” will expand, yet filled in by existing trees in the background to continue to provide the experience of being in an enclosed space.Pruning of several other cedars to provide light and future growing space for plant collections.
    • 2 on the west side in the “twig bed”
    • 1 on the south side next to the Chinese red birch grove
    • 1 on the east side growing over several camellias and other collections
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The “Lost” Enkianthus Grove in Washington Park Arboretum

August 8th, 2014 by UWBG Horticulturist

Does anyone reading this know where our arboretum’s “lost” Enkianthus grove is located? By “lost”, I mean extremely well-hidden under a dense canopy of western red cedars and other trees.

photo

Enkianthus specimens previously “lost” in the overgrowth.

Enkianthus are shade-tolerant shrubs, but NOT “black-hole” shade tolerant. Like most living plants, they do need light to grow and thrive.  It’s a bit embarrassing, but I can honestly say, during my 30 plus year tenure on the UWBG horticulture staff, I don’t recall ever working in the area for longer than maybe a day cleaning up after a storm or pruning a few of the bigger trees. And, we definitely did not pay any attention to the main attraction – a grove of over 50 Enkianthus specimens, mostly all E. campanulatus (red-vein enkianthus) and over 70 years old! Well, the answer to the question above is Rhododendron Glen, encompassing several grid maps (14-2E, 14-3E and 15-3E).

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Accession number 2352-37, this Enkianthus campanulatus was planted in 1937.

Now for the good news. Thanks to funding designated for Rhododendron Glen, our horticulture staff has taken on the project to restore the grove for all to be able to once again, after a very long hiatus, enjoy its natural beauty and splendor throughout the year.

The project scope includes the following to improve the health and display of the Enkianthus grove:

  • Increase light conditions through selective understory brush clearing, tree removals and pruning
  • Open view corridors and a cleared natural pathway for visitors to walk from the upper Rhododendron Glen pond area down to the lower “Lookout” pond
  • Improve health of the Enkianthus through practicing sound horticulture: mulching, watering and fertilizing the grove

For more information about the ornamental shrub, Enkianthus campanulatus, go to Wikipedia website below:

http://en.wikipedia.org/wiki/Enkianthus_campanulatus

 

 

 

 

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Harbinger of Spring in Seattle – Flowering cherries on Azalea Way!

March 20th, 2014 by UWBG Horticulturist

Cherry photoMost visitors experiencing the beauty of our historic Azalea Way flowering cherries from now through May probably have no idea of how intensive maintaining their health and prolonging their longevity truly is for the UW Botanic Gardens horticulture staff.   Just ask our Integrated Pest manager, Ryan Garrison. Ryan with staff support spends many a day throughout the year monitoring and controlling the numerous diseases and insect pests our 175 plus cherries are prone to suffer from. Our rainy climate doesn’t help one bit either, especially when dealing with our most notable disease during blossom time;  a fungus known as Cherry Blossom Brown Rot. Yucko!  The good news is any new cherries we plant need to show a reasonable level of resistance. The not so good news is many of our older earlier bloomers, the ones extremely susceptible to the brown rot fungus,  need to be protected with fungicide applications during their bloom period.  As with all of our pest issues, we start with cultural and mechanical control efforts before resorting to chemical controls. The following Integrated Pest management (IPM) program discusses our best management practices for the control of blossom brown rot.  If you are interested in planting cherries for your home garden, I’ve included a list of cherries recommended for our PNW climate.  All have good to excellent resistance to blossom brown rot.

14 new cherries will be planted along Azalea Way, Spring of 2014! Thanks to the UW being awarded funds from the Nationwide Cherry Blossom Tree Planting Initiative grant co-sponsored by the Consulate-General of Japan in Seattle and other supporting local community organizations.

Cherry Blossom Brown Rot - causal fungal agent known as Monolinia fructicola. The fungus overwinters on infected twigs and dried fruit on the tree or ground.  The fungal spores are spread in the spring by wind and rain through the blossoms, causing twig dieback.  As part of the UWBG IPM program, moving toward our goal of eliminating the use of all synthetic pesticides is our ultimate goal.

IPM relies on many strategies to manage plant health care. 

  • Proper ID of the pest and its life cycle
  • Regular monitoring of the plants
  • The use of physical, mechanical, cultural, and biological controls
  • Chemical controls used as a last resort*
  • Least toxic chemicals used

* All spray applications are in compliance with WSDA pesticide regulations.  Sign postings are located at all entrances and Graham Visitor Center. Spray applications are scheduled based on timing and weather. We do our best to apply when public are not present. For more information, pls contact, David Zuckerman at 206-543-8008 or dzman@uw.edu

The cherries are pruned in early fall  to remove infected twigs and improve air circulation.  Tree rings are given a fresh coat of mulch in the fall to bury any infected plant material that may be on the ground.  In our Cherry Replacement program we are only using cultivars that are resistant to Blossom Brown Rot.

Cherries recommended for the PNW:

    • Prunus‘Berry Cascade Snow’
    • Prunus ‘Kwanzan’ syn. ‘Sekiyama’
    • Prunus‘Pink Flair®’
    • Prunus‘Royal Burgundy’
    • Prunus‘Shirofugen’
    • Prunus‘Shirotae’
    • Prunus‘Snow Goose’
    • Prunus subhirtella var. ascendens
    • Prunus x yedoensis ‘Shidare Yoshino’
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Coming Attractions for 2014 in Horticulture and Plant Records

January 21st, 2014 by UWBG Horticulturist

There is much to look forward to in 2014 for the University of Washington Botanic Gardens (UWBG) horticulture and plant records staff. It will be a rare year of “normality” between capital project implementations, the completed 2013 Pacific Connections Gardens (PCG) New Zealand (NZ) forest exhibit and the looming 2015 multi-use trail. Our resources will be focused on smaller scale deferred maintenance projects of several gardens and plant collections, catching up with plant labeling and mapping of our Pacific Connections Gardens and embarking on a few recently awarded grants.

Washington Park Arboretum (WPA)

On the grants front, this spring, Azalea Way and the Japanese Garden will be receiving new cherry trees, along with funding to support future maintenance, thanks to the Japanese Embassy’s Nationwide Cherry Blossom Planting Initiative. Fourteen cherries will be installed of various types, ranging from the tide-and-true classical hybrids to the newer, disease-resistant cultivars. We hope to tap into the services of our volunteer Azalea Way stewards force to help in their planting, establishment and future care.

Club Car vs JD Gator

Club Car vs JD Gator

We just heard that we were awarded $33 thousand from the UW Green Seeds funds, a grants program that engages our UW community in sustainability research that will have a direct affect on reducing UW campus’ carbon footprint. Our 1 year study will allow us to purchase 2  new utility vehicles, 1 electric and 1 bio-diesel, which will be the test subjects of a research project titled:  “Grounds Utility Vehicle Carbon Footprint Comparison Study”. Results and conclusions will be disseminated at the end of the study to UW Grounds Management, Seattle City Parks and Recreation, and other local municipalities and private organizations that employ utility vehicles to perform grounds maintenance tasks.

Our curator, Ray Larson, is busy developing plant lists and procuring new plants for refreshing and embellishing many plant collections displays and exhibits. Our horticulturists will be installing exciting new cultivars and hybrids in the PCG entry gardens of Australia, Cascadia and China.  Also, wild-collected specimens from our container nursery inventory will be planted out in the future China forest portion which was cleared during the NZ forest construction last year. We hope to receive several tree peony cultivars from the Seattle Chinese garden. The  American Peony Arts and Cultural Association is promoting Luoyang peonies. These donations may be planted in the PCG China entry garden, in our original peony display along Arboretum Drive and/or over at the Center for Urban Horticulture.

Overgrown Camellias ready for renovating!

Overgrown Camellias ready for renovating!

Other gardens and collections of 2014 focus for small-scale renovations and/or new plantings include the Winter Garden, Camellias, Hollies, Maples, Pinetum and Viburnums.

On the Plant Records front, catching up with our backlog of labeling and mapping will be a major goal for all UWBG gardens and collections, specifically PCG’s NZ forest and Chilean Gateway. Mapping our collections has moved into the 21st century using sophisticated survey equipment to gather Geo-referenced points that will enable all sorts of modern applications for staff and public alike who want more information on the locations and data of our plant collections.

Center for Urban Horticulture (CUH)

The horticulturists at CUH will certainly not be any less busy or ambitious  in 2014 than those at WPA. The following projects are either underway or in the works:

  •  New plantings for the McVay stairs will include a new bench, bringing back the solar fountain from WPA and, if room allows, also incorporating a container or two.
  • Our “face” along 41st Street is undergoing a much needed “lift.” After the new fence is built, there will be opportunities for new plantings along it. Also, expect to finally see our “Welcome” signs get installed onto the long awaiting stands at both ends of our frontage.
  • Speaking of signs, the tired-looking interpretive signs in the Orin & Althea Soest Herbaceous Display Garden will be replaced shortly. Also, keep your eyes open for changes and new plantings in a few of the Soest display beds.
  • If funding comes through, the Fragrance Garden bed along NHS Hall is on the schedule for renovation this year as well.
  • Goodfellow Grove will continue to be a focus of renovation, with considerable restorative pruning and thinning beds, path and lawn improvements.
  • Later this year, clearing of vegetation around Central pond in the Union Bay Natural Area will take place in hopes of providing more habitat for shore-birds and increasing their diversity.
Solar Fountain to return to CUH

Solar Fountain to return to CUH

As you can see, there’s plenty of work to be done by the UWBG horticulture and plant records staff in 2014. And, yes, a sigh of relief to be able to broaden our horizons beyond all-consuming capital projects for the year to focus on these smaller maintenance improvements of our established gardens, grounds  and collections.  Please stay tuned for further posts and photos on many of these exciting changes to take place in 2014 at our botanic gardens.

 

 

 

 

 

 

 

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Elisabeth C. Miller Garden and Washington Park Arboretum staff walk, talk and gawk

January 11th, 2014 by Kathleen DeMaria, Arboretum Gardener

The Washington Park Arboretum (WPA)  staff was delighted to host the staff and interns from the Elisabeth C. Miller garden for an educational walk and talk Wednesday January 8th. The wind and rain didn’t stop this intrepid group of horticulturists from walking the Pacific Connections Gardens and the ever-changing,  always stunning Joe Witt Winter Garden.  The Miller Garden staff was gracious enough to bring several plants to gift to the WPA, continuing the Miller family’s legacy of supporting the University of Washington Botanic Gardens. A big thank you goes out to Roy Farrow (a former Miller garden intern and current WPA horticulturist) for coordinating this meeting of  plant-world minds.

 

MillerGardentoursWPA2014

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A Kiwi Botanist in our Mist

October 31st, 2013 by Kathleen DeMaria, Arboretum Gardener
Bec shows Kathleen how the Maori harvest Muka, the inner fibers of Harakeke (Phormium tennax) to be used in the fabrication of  various fibers used as rope, roofs, shoes, etc.

Bec shows Kathleen how the Maori harvest Muka, the inner fibers of Harakeke (Phormium tennax) to be used in the fabrication of various fibers used as rope, roofs, shoes, etc.

The misty October revealed a great surprise to New Zealand horticulturist Kathleen DeMaria while she was installing signs for the new ‘Lookout Loop Trail’ near the recently restored Lookout Gazebo.  Kathleen and fellow horticulturists Rhett Ruecker and Roy Farrow peeked through the fog and barely saw a highly engaged woman taking notes on the new New Zealand Forest.  As it turns out, this woman was Rebecca Stanley,  Auckland Botanic Gardens Education Officer and former plant ecologist with the Auckland Regional Council. Bec, visiting the US west coast on holiday, graciously offered to spend some time with Kathleen in the garden on the following Saturday. The two plant-geeks spent 4 hours walking through the foggy New Zealand forest. Bec’s encyclopedic knowledge regarding the ethnobotanic uses of plants and the cultural requirements of plants was astonishing, and her willingness to share it all, as well as her educational delivery style were delightful. She offered sources for seed, suggestions for books, names, emails and information about who she knows throughout New Zealand that would be interested and willing to help UWBG grow our own New Zealand forest.  Personally, and as a representative of the University of Washington Botanic Gardens, I would like to thank Rebecca for all of her time and information, it was a delightful walk in the garden topped off with a delicious lunch at Cactus Cafe and a visit to the downtown library. Thanks so much, Bec! All photos courtesy of Julie Postma.

Dew  on Phormium tennax in the New Zealand garden

Dew on Phormium tennax in the New Zealand garden

Bec helps Kathleen assess the health of Olearia nummulariifolia in the NZ forest

Bec helps Kathleen assess the health of Olearia nummulariifolia

Bec discussing perecipitation patterns in the Otago region of NZ

Bec discussing precipitation patterns in the Otago region of NZ

One theory for the 'New Zealand Dead Look' of so many plants: Moa, wingless birds now extinct, were thought to have poor eyesight, so plants would mimic dead plants to avoid predation by these voracious herbivores

One theory for the ‘New Zealand Dead Look’ of so many plants: Moa, wingless birds now extinct, were thought to have poor eyesight, so plants would mimic dead plants to avoid predation by these voracious herbivores

seed capsule of Leptospermum scoparium, or mānuka, the tea tree. This name arose because Captain Cook used the leaves to make a 'tea' drink when he and his scurvy sickened crew arrived in New Zealand

Seed capsule of Leptospermum scoparium, or mānuka, the tea tree. This name arose because Captain Cook used the leaves to make a ‘tea’ drink when he and his scurvy sickened crew arrived in New Zealand

Light breaks through the fog on our walk back to the Visitors Center

Light breaks through the fog on our walk back to the Visitors Center

View from the woodland garden...deciduous trees are rare in New Zealand so Bec was delighted by our spectacular fall color

View from the woodland garden…deciduous trees are rare in New Zealand so Bec was delighted by our spectacular fall color

 

 

 

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Dutch Elm Disease in the Washington Park Arboretum

September 3rd, 2013 by UWBG Arborist, Chris Watson

Recent test results from Washington State University Puyallup Plant & Insect Diagnostic Laboratory confirmed the first case of Dutch Elm Disease (DED) in the core area of the Washington Park Arboretum.  The tree, a 45 year old Guernsey Elm (Ulmus minor ‘Sarniensis’), had been suffering from mechanical injury to the root crown and annual infestations of the Elm Leafminer, an insect that that feeds on elm leaves.  Over the past year, a significant portion of the tree began showing symptoms similar to DED.  Twig and branch samples from the tree showed dark staining in the cambium, which is a typical sign of DED.  The samples were sent to the WSU lab in Puyallup, which resulted in a positive diagnosis for DED.  The Guernsey Elm has been removed.

Management of Dutch Elm Disease will include frequent monitoring for signs and symptoms of the disease, sanitation pruning, prompt removal of severely infected trees, and root graft disruption when necessary.

For more information on Dutch Elm Disease, click here:

http://www.seattle.gov/transportation/pdf/sdot2dedbrochure.pdf

or here:

http://pnwhandbooks.org/plantdisease/elm-ulmus-spp-dutch-elm-disease

Ophiostoma picture

Dutch Elm Disease fungus (Ophiostoma sp.)
Photo courtesy of WSU Puyallup Plant & Insect Diagnostic Laboratory

Guernsey Elm (Ulmus minor ‘Sarniensis’)
Photo courtesy of University of Washington Botanic Gardens

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