All native planting restoration projects require existing plants (typically grass and invasive species) to be killed and removed (one of the techniques used is prescribed burning). This allows for areas to be seeded and planted with a diverse mix of native plants. Maintenance may include mowing and burning to reinvigorate growth of the beneficial species, along with spot-spraying to remove noxious weeds. Native plantings often take a few years to "grow up" and "fill in."
- Hasenbank Woods
- Lake Middle School and Middleton Elementary School Greening Project
- Ojibway Park
- Pollinator Corridor
- Vegetation Management Around Stormwater Basins
- Valley Creek Park
Goats and Restoration
This site is located on city property that receives maintenance only on an as-needed basis (hazardous tree removals). That said, the overall site plan being developed by the City and Watershed District would provide a combination of connected project components that include improved ecological integrity of Fish Lake Wetlands, naturalized stormwater features to protect and improve water quality in Powers Lake and the full restoration of Oak Savanna and Oak Woodlands in the core of this site with the Hasenbank Woods. Located within a nearly fully developed portion of the city, the 61 acres of Fish Lake/Hasenbank Woods/Stormwater BMP will provide a large block of connected native plant community green space immediately east of Powers Lake and it's associated forested edge.
Hasenbank Woods provides an ideal location, on untilled soils, for the restoration of Oak Forest and Oak Savanna. Abundant and healthy mature oaks currently on the site provide a great opportunity for the restoration of oak dominated communities. Without restoration and maintenance, the native plant components of Hasenbank Woods will likely decline through the continued growth and dominance of Common Buckthorn and Non-native honeysuckles. This will eventually lead to the complete loss of the natural community components within the woodlands as regeneration of native species diminishes. Returning diverse native forest and savanna communities will provide enhanced habitat opportunities for a variety of native pollinating insects, birds and other wildlife adjacent to diverse wetland and upland native plant communities. In addition, existing trails along the margins of the site will offer substantially enhanced opportunities for park users to observe and appreciate ecological function on this site.
The Watershed District and City will use a multi-year combination of mowing followed by animal grazing to clear woody invasive species and encourage recruitment of native plant species through regrowth, replanting and seeding. This slow approach has been very successful at removing heavy buckthorn stands and subsequent garlic mustard infestations by weakening these plants numerous times as they resprout. The approach reduces the use of herbicides early in the process and allows for more targeted applications on already weakened individuals. This in turn reduces the potential for overspray and long term effects of herbicide use.
Tentative Project Schedule
Schedule of activities in the coming years is as follows:
- Using qualified native plant contractors, woody invasive shrubs were mowed and mulched by forestry mowers (winter, 2022). Desirable native woody species were identified and protected during forestry mowing. Some hand cutting will complete this work in summer, 2022.
- Prescribed goat grazing will occur for up to three full seasons in spring and fall to reduce the viability of invasive shrub species and knock back the expected flush of garlic mustard following initial removals.
- SWWD and City staff will survey the woodlands to assess canopy trees for removal. Removals will seek to create a more open canopy in Savanna areas (<50) and more closed canopy in Oak Woodlands (~70). Tree removals will first be driven by control of Oak Wilt, Emerald Ash Borer and Dutch Elm Disease where potential or present, then by removal of less desirable species (boxelder, young cottonwood and some black cherry) appropriate to promote target oak communities.
- Seeding of simple grass only native seed mixes will occur in the first year to provide ground layer cover and erosion control, but still offer opportunities to control broadleaved weeds. Mixed grass and forb broadcast seed rains will continue through subsequent years. Seeding just prior to grazing will help with seed to soil contact as goat hooves press seed into the ground.
- Project will create conditions to support future prescribed burns which will occur in future years to control the return of invasive shrub species.
- Tree, Shrub and Forb species for replanting will be identified and planted following assessment of site recruitment following invasives controls.
For years, buckthorn removal relied on a combination of hand pulling smaller stems and cutting/treating of small and large individuals with hand tools and herbicides. While both methods can be successful, they are both labor intensive among other drawbacks. Hand pulling can be very disruptive to soils, creating a bed for invasive weeds to easily establish and disturbing soil structure and underground ecosystems. Cutting and treating with herbicides can sometimes have negative and longer terms effects on recruitment of native species due to residuals or overspray.
Goat grazing to control buckthorn, honeysuckle and garlic mustard has proven effective in areas where these invasive species have become dominant. While the Hasenbank Woods contains some native shrub and herbaceous species, common buckthorn was present in all locations and generally the dominant shrub. The site was at a point where a reset of the ground and shrub community was needed to create the potential for long term maintenance and resilience.
All approaches to remove significant buckthorn infestations require a multi-year effort to weaken and kill the species. In Hasenbank Woods, forestry mowing, completed in winter 2022, cut and mulched in-place the large woody buckthorn individuals and shattered the stems, inhibiting rapid regrowth. The mowing will now be followed by five to six rounds of spring and fall grazing over three years. Goats favor the soft stems of woody undergrowth and will munch the buds and twigs of these plants, significantly reducing their ability to photosynthesize as shrubs struggle to create leaves. Successive rounds of grazing continually weaken and kill these plants. Goats also target garlic mustard, so timing the goat grazing to occur just prior to flower and seed set of this species has proved to reduce the aggressive establishment of this species which typically shows up after buckthorn has been removed.
An additional means of protecting soils, and establishing native species understory within the woodlands and savanna will involve broadcast seeding of native grasses and flowers immediately prior to prescribed grazing. As the goats wander the site, their hooves press seed into soils throughout the site and essentially do work that often requires machinery that is difficult to operate in woodland settings. Seeding will take place using this method in each of the three years to begin building replacement cover as buckthorn is removed.
Following the third year of grazing, herbicide treatments will target the remaining (weakened) invasive shrub species. Herbicide treatments at this time will be far less intensive than using the approach early in the process. Treatments will be highly targeted at remaining shrubby invasive species. Native flowers, grasses, sedges, shrubs and understory trees may be planted to augment site diversity.
Beyond Hasenbank Woods
As Hasenbank Woods sits between Fish Lake wetlands and Powers Lake. The City and Watershed District are considering additional improvements. In 2022, the Watershed is leading an evaluation of the vegetation in and around Fish Lake. Pending those results, vegetation improvements may begin in the wetland and adjacent stormwater ponds in 2023 and extend for numerous years after. The partnership is also evaluating additional trail, educational and wayfinding features in conjunction with design of stormwater best management practices (BMP’s) in the open space directly east of Saint John’s Drive. The stormwater BMP’s will be designed to provide water quality benefits to the runoff before it reaches Powers Lake. Community and neighborhood engagement will occur for each phase of the project, stay up to date by signing up for InTouch Eco-Interest!
A project partnership between South Washington County Watershed District (SWWD), Independent School District (ISD) 833 and the City of Woodbury to plant 67 trees and replace 15 acres of unused turf with native plants and trees. More information can be found on the SWWD website.
Pictured: Elementary and middle school classes helped plant trees. These "Keepers of the Trees" promised to share the important benefits of trees with younger students on the school campus.
The City of Woodbury received a grant from the State of Minnesota to restore the vegetation in Ojibway Park. This work is planned to continue through summer 2022.
This winter, removal of invasive woodland species like buckthorn will make the park look messy, but seeding in the spring and fall will improve the look of the park. Please bear with the mess while we work to improve the natural vegetation in the area.
From Ojibway Park to Bailey Road, more than 11 acres of grass have been converted to pollinator prairie along the trail corridor. This project is funded through the Butler Foundation in partnership with Great River Greening. Volunteers put the first plants into the ground in May 2017. More planting updates will be provided as they become available.
Pictured: Volunteers gathered to help plant the initial installation of pollinator plants last May.
The City of Woodbury owns and maintains more than 500 stormwater basins for flood control and water quality benefit. The city has started the process of maintaining vegetation around basins along trails and in parks for additional water quality benefits. This also assists with habitat creation for pollinators, birds and other beneficial wildlife. Each year we'll be starting restoration on additional basins around the city.
Similar to the Ojibway Park Project, the city received a grant from the Department of Natural Resources (DNR) to improve the habitat of the oak woodland, oak savanna, prairie and wetlands. This project complements the park improvements made in 2021 and 2022. The vegetation establishment project will start summer 2022 and be completed by summer 2025.
Work in the winter months will be widely removal of invasive woody species, such as Buckthorn, followed by selective treatment. The spring, summer and fall months will focus on the prairie, wetlands and understory vegetation through selective removal and seeding. Numerous prescribed burns are anticipated throughout the project.
Find more information on the Park Projects page.