Landscape restorations limited by previous actions
OSHKOSH – Although disturbed landscapes cannot be returned to their original natural condition, that's not a reason to avoid establishing native flora and fauna on urban residential and industrial sites and along recreational trails.
That was the message from landscape architects Rob Holly and James Coletta of LandWorks Inc. at Sussex during the 21st annual “Toward Harmony with Nature” conference sponsored by the Fox Valley area chapter of Wild Ones. The company specializes in the design of urban gardens with a multitude of native plant species.
The presenters explained that natural ecosystems are intricate and complicated after having evolved from interactions over millions of years. Derived through a combination of weather, soils, climate, water availability and site elevation, those ecosystems can be augmented by humans today with soil amendments, restoration of native plants and weed suppression.
Native planting challenges
In many cases, plantings of native species face a variety of challenges, the presenters warned. They cited possible compaction and nutrient imbalances of soil that has been disturbed, limited spaces for growth in the surrounding environment, and pressure from weed species in the site's bank of seeds that would germinate for many years when the soil is disturbed again.
If the urban garden site can mimic native environmental conditions, then native plants would be able to establish extensive root systems, not require much maintenance, reduce water needs, not require fertilizer, pesticide, or herbicide, and provide food and shelter for wildlife, the presenters observed.
In its approach, LandWorks Inc. seeks to create “adaptive landscapes” that provide the benefits of native landscapes in new settings by using “tough native plants” that can overcome pressure from weed species and that are resilient to adverse changes in their environment.
Property owners and managers who are interested in doing that are advised to consider the short and long term goals for the site and fit them with the size of the landscape, the structure of the new plantings and the plant species. The singular or inter-related goals could be habitat for birds and pollinators, human aesthetics, soil rejuvenation and groundwater recharge.
Among the factors to consider are the sun/shade distribution at the site, soil composition, wind, slope, hydrology, infrastructure and any micro-climate conditions. Other considerations are the views, safety concerns, regulations, traffic, public perception, pests, the site history and the amount of maintenance that will be required.
The next steps include creation of a site plan, a design for the placing of the plants, and putting the right plants in the right place. Specific attention needs to be given to avoiding encroachment on adjacent private or public sites, selecting species that are easily distinguishable from undesirable species, making the result visually attractive, and taking advantage of plant combinations suitable for the site, Holly and Coletta advised.
Three principles which apply to small urban gardens are scale (avoiding the native grasses that can overwhelm a small site), spreading (the seeding, suckering, or rhizomatic activity that spill over to neighboring properties) and tidiness (avoiding a messy, overgrown, of weed infested appearance). Other concepts that apply for visual appeal include repetition and massing; layering, texture and color; and planning for potential growth of the site.
At all points in the process, the LandWorks architects emphasize that neighbors need to be informed about what's been done. Beyond that, they advise honoring a defined property line border, reminding the neighbors about how salt damages soil structure and many species, and asking them not to blow mowed grass onto one's property because of the possibility that it could contain weed seed.
In addition, Holly and Coletta suggest trying to connect with neighbors to develop conservation corridors that would greatly expand the impact. They note that some native flora and fauna need a certain minimum area in order to thrive.
A successful project should increase appreciation of the subtle beauties of native plants; exhibit a harmony between the newly designed landscape and native ecosystems; nurture a heightened recognition of the diverse prairie, woodland, and wetland landscapes of the Midwest; and provide the owner with a largely self-maintained landscape, Holly and Coletta indicated.
While “no landscape is self maintaining,” Holly and Coletta promised maintenance should be reduced once native plants are established but they also call for monitoring to control exotic and pest plants and for controlling the water level to make it appropriate for the plant species.