April 7th, 2012 by UWBG Horticulturist
Join the Student Conservation Association
(SCA), the University of Washington Botanic Gardens
(UWBG), and Seattle Parks and Recreation
for a day of fun service projects at the Washington Park Arboretum.
When: Saturday, April 14, 2012. 9:00am – 2:00pm
Where: Washington Park Arboretum, 2300 Arboretum Drive E, Seattle 98112. (Meet in the Meadow—a 5 minute walk south of the Graham Visitors Center.)
What to bring: water bottle, sack lunch, travel mug for a hot drink, sunscreen, rain gear, long pants, layers of clothing, and boots. Some snacks & drinks will be provided. Tools, gloves, snacks, environmental education, and project materials will be provided.
- Student volunteers having fun spreading mulch at the Arboretum at a previous Earth Day event.
PLEASE RSVP to the SCA
For more information and to register, visit thesca.org/seattle, email email@example.com or call 206.324.4649
Map of project locations at Washington Park Arboretum
In partnership with the Seattle Parks and Recreation, UW Botanic Gardens and Woodland Park Zoo.
March 8th, 2012 by UWBG Horticulturist
Most 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.
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 firstname.lastname@example.org
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‘Snow Goose’
- Prunus subhirtella var. ascendens
- Prunus x yedoensis ‘Shidare Yoshino’
February 28th, 2012 by UWBG Horticulturist
1) Rhododendron arboreum hybrid
- The earliest, longest blooming rhododendron in the Arboretum (November-March!)
- Due to its floriferous nature, even in the coldest winters when it sustains bud blast from a deep freeze, it usually never fails to flower afterwards.
- Located in Witt Winter Garden, this rhododendron is worthy of naming and becoming a WPA plant selection.
2) Rhododendron ‘Cilpinense’
- Hybrid between parents of two Chinese spp., Rh. ciliatum and Rh. moupinense
- Compact, low-growing rhododendron that blooms in late February into March
- Nice grouping located in Winter Garden, bed F
3) Rhododendron mucronulatum ‘Cornell Pink’
- My personal favorite harbinger of spring rhododendron
- Species is native to Korea, a.k.a. Korean rhododendron
- Can’t miss ‘em beginning to flower at north end of Azalea Way, x from GVC
4) Rhododendron ririei
- Large rhododendron, best in partial-shade for vivid magenta-purple color to show
- Native to Mt. Omei, W. Szechwan and flowers late February – early March.
- This specimen is located in Loderi Valley, southwest bed with hemlock cvs
5) Rhododendron strigillosum
- Rare, rich red flowering rhododendron in late February – early March
- Stiff, bristly leaf-stalks and narrowly-oblong leaves provide added texture and show
Several new specimens located in Witt Winter Garden.
February 7th, 2012 by UWBG Horticulturist
“Guardian Series” Port Orford cultivars
Chamaecyparis lawsoniana ‘Yvonne’
The future health outlook bodes well for what many consider to be our finest native conifer in the PNW, Chamaecyparis lawsoniana, Port Orford cedar and its many cultivars. Port Orford cedars have been under seige for many years from its worst enemy Phytophtora lateralis, a soil-borne pathogen that is especially virulent in wet soils, and essentially spells a death-sentence to this majestic tree once its roots are infected. There is no cure, but there is a preventative practice known as plant resistance. Dr. Everett Hansen at Oregon State University has developed a Phytophthora lateralis resistant root stock. And now, thanks to the development and research labs of Monrovia, they have introduced into the trade numerous Port Orford cultivars grafted with the phytophthora resistant root stock. These grafted Port Orfords are known as The GUARDIAN ™ Series .
Through a generous donation from Monrovia, the Washington Park Arboretum will be trialing 6 GUARDIAN ™ Series Port Orford cultivars, as well as, the type species grown on its own root. We have chosen 5 known “hot-spots” (either cultured or symptomatic of phytophthora infested soils) throughout the arboretum. There are 2 specimens each of the cultivars and the type. We’ll be monitoring and reporting on their growth and health for a period of 5 years. Knowing the extensive research and development that has gone into The GUARDIAN ™ Series Port Orfords, after the 5-year trial, I expect a 100% survival-rate. Stay tuned for periodic updates on this exciting plant trial study.
September 23rd, 2011 by UWBG Horticulturist
And the astonishing United Way ”Day of Caring” numbers are in!
103 total volunteers working 417 hours!
Representing 4 companies/corporations: AT&T, Japan Business Association, Microsoft, Nordstrom
Completing 5 projects:
NOTE: 1 truckload is apporximately 3 yards.
Special thanks to our sponsoring partner, The Arboretum Foundation – especially Cynthia Welte and Rhonda Bush and of course our other managing partner, Seattle Parks and Rec. Without you guys, Day of Caring wouldn’t be possible.
Blackberry Galore in Rhododendron Glen
Microsoft staff laboring in the Pinetum
August 22nd, 2011 by UWBG Horticulturist
An expansion of the Azalea Way lawn path is proposed.
Historically the Azalea Way lawn path experiences 8-9 months a year that are very wet making access difficult. In 2009 a crushed rock path was added to the middle of Azalea Way from Boyer Parking lot to the Woodland Garden. The proposed improvement will add 700 feet of 6 foot wide crushed rock path from the Woodland Garden to the Lynn Street Bridge Trail.
Parks anticipates the construction of the path will take place over the first two weeks in September 2011. We will work in sections to minimize the impact on users.
The project is funded by generous donation from the Arboretum Foundation.
Thank you for your support and patience during this project.
For more project information please contact:
Lisa Chen, Park Horticulturalist Seattle Parks and Recreation 206-233-3777 or email@example.com
August 4th, 2011 by UWBG Horticulturist
UW Botanic Gardens has begun its 4th year of the 5yr Dept. of Ecology, Garden Loostrife eradication project.
Our contractor, NW Aquatic Eco-Systems, has scheduled initial spray applications to commence on July 31 – August 1. Another application will be scheduled week of August 6th. Postings of project and current spray dates are located at all public accessible waterfront locations. There will be a final follow-up application in September.
Lysimachia vulgaris, Garden Loosestrife, a non-native wetland species is invasive in this area. State listed as a class B noxious weed, it requires control by the land manager UW Botanic Gardens as mandated by King County Noxious Weed Control Board.
- Approximately 5 miles of shoreline property bordering Union Bay including Foster and Marsh Islands in the Washington Park Arboretum
- An initial and follow up spray application to occur between July 15 and October 1
- Both shoreline and land side application of the herbicide Renovate 3 (triclopyr), a selective broadleaf herbicide.
- Non toxic to fish and their food web.
- No significant risk to birds or mammals
June 28th, 2011 by UWBG Horticulturist
WPA tree removal scheduled for Thursday (6/30):
Tsuga heterophylla (Western Hemlock)
WPA Native Matrix
Location: Along Arboretum Dr. E., field nursery fence row. Grid 28-4E
Status: Standing dead, in decline for several years prior
Targets: Pedestrians, vehicular traffic along Arboretum Dr and other UWBG plant collections
Cause: Cumulative root impacts from road and infrastructure maintenance and develpment.
UWBG tree crew will perform removal and responsible for all public safety precautions. Drive will be kept open, traffic will be detoured around work zone.
Postings on-site, Graham Visitor center and on UWBG website.
UW Botanic Gardens
June 21st, 2011 by UWBG Horticulturist
WPA tree removal scheduled this week: 6/22-24
UWBG plant collection accession #: 88-62-A
Acer rubrum var trilobum (Carolina Red Maple)
Location: North Pinetum, aka Conifer Meadows, Grid 42-4W
Status: Standing Dead
Cause: Unknown, however suspect of phytophthera and abiotic stress during 2007 irrigation mainline installation. Evidence of fungal disease under bark.
UWBG tree crew will perform removal and is responsible for all public safety precautions and possible trail closures.
Postings also on-site and at Graham Visitors Center
UW Botanic Gardens
June 7th, 2011 by UWBG Horticulturist
A loosestrife by any other name. . .
If you have trouble remembering this plant’s name, you might try thinking of the strife it has let loose on our wetlands.
In 2009, the Department of Ecology awarded the UW Botanic Gardens a 5-year grant for the control of garden loosestrife (Lysimachia vulgaris), a class B noxious weed mandated for control by the King County Noxious Weed Control Board. Now we’re hosting a symposium featuring the latest observations and expertise on aquatic weed management.
In his keynote address, Steve Manning, founder and president of Invasive Plant Control, Inc., will present economically and environmentally sound techniques for controlling invasive aquatic weeds. You’ll also hear from King County Noxious Weed Specialist Katie Messick and representatives from the UW Botanic Gardens and Seattle Parks Department. The afternoon will be devoted to a kayak or walking tour (your choice) through Lake Washington’s wetlands, one of garden loosestrife’s primary haunts in this region.
Designed for professional audiences, this symposium is open to everyone interested in aquatic weeds and their control.
Managing Aquatic Weeds: Challenges and Opportunities
Wednesday, July 13, 9:00 AM-3:30 PM
Graham Visitors Center, Washington Park Arboretum, 2300 Arboretum Dr. E, Seattle
Professional Credits: WSDA, WSNLA (pending)
Symposium with Kayak Tour, $55; Symposium with Walking Tour, $30
Box lunch included when you register by July 10: 206-685-8033 or online