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.
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).
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:
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.
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 email@example.com
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’
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.
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.
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.
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.