Native Plants for Sustainable Landscapes: Establishment and Management of Lakeshores and Gardens

Native plants can be used around homes and in gardens to create sustainable landscapes. Most native plants are perennial and have extensive root systems that hold soil and slow runoff. Persistent stems, leaves, and flower parts which remain through the winter also reduce runoff, especially in the spring, as snow melts and rainfall begins before new growth is present. Particulate matter accumulates around these native plants and the plants themselves absorb chemicals such as nitrogen and phosphorous that would otherwise enter the runoff.

Native plants have many positive characteristics. Native plants used as buffer strips along water margins slow runoff and absorb nutrients. They are also self-sustaining, and they support wildlife including beneficial insects, pollinators, and native birds.

Successfully growing native plants requires an understanding of the evolutionary adaptations plants make to specific light and soil moisture conditions. Prairie plants have adapted to dry, sunny uplands, while woodland plants tolerate shade. Wet meadows contain plants species tolerant of sun and wet soils, while plant species in the emergent zone grow with their stems above water and their roots in water. Submerged or floating leaf plants have stems and leaves under water with some parts above water.

Once established, these landscapes can be managed by using principles of Integrated Pest Management, which emphasize lower pesticide usage. These sustainable landscapes require less chemical treatment, reducing the amount of chemicals put into the environment which have nontargeted effects on the ecosystem, its plants, and its animals.

This bulletin contains information on sustainable landscaping in watersheds, sustainable management of such landscapes, lists of vendors who sell native plants and erosion control materials, and an extensive list of recommended native plants. Landscapes and their management are described for drier upland gardens as well as shoreline buffer strips.

Traditional Landscapes

Sustainable Landscape

Convert upland gardens and shorelands to wildlife havens by planting native species and practicing sustainable management. (MNDNR). Copyright 1998, State of Minnesota, Department of Natural Resources, Section of Fisheries.

Sustainable Landscapes Protect Water Quality

• Erosion is reduced. Since upland plants hold soil and shoreline plants reduce wave and ice action, erosion is reduced and soil is less likely to erode into the water.
• Runoff volume is reduced. Upland landscapes and shoreline buffer strips slow down water so it soaks into the soil, rather than racing down to the lake.
• Herbicides, pesticides, and fertilizers are reduced or eliminated from runoff. Plants adapted to their environment often require fewer pesticide and fertilizer treatments.
• Plant nutrients are removed from lake water. Plants absorb nutrients which would otherwise increase the growth of water-clouding algae.

Sustainable Landscapes Increase Biodiversity

• Increased numbers of plant and animal species help make a landscape sustainable. A variety of plant species provide food and shelter for birds and beneficial insects which reduce insect pest outbreaks.
• Fish habitat is enhanced with aquatic vegetation. Emergent vegetation provides habitat for spawning fish and fry. Water quality improvements increase fish production.
• Native plants and animals are conserved. Many plants have become rare as their habitats have been converted to farms and towns. Native plants in home landscapes support a food web including birds, insects, and other animals.

Sustainable Landscapes Provide Social Benefits

• Property values are increased. Beautiful vistas from the home and water are created by the use of native plants. The variety of colors and plant forms, the energy and activity of birds and insects, and the seasonal changes of both plants and animals provide diversity and visual enjoyment. The house may be partly hidden by vegetation for greater privacy and a natural looking lakeshore. Trees and shrubs reduce noise of jet skis and boats. A landscaped lot adds value to the house.
• Little maintenance is required on established landscape. Initially, some weeding may be necessary. Once the plants have become established, there will be less time spent on mowing, planting of annual bedding plants, chemical spraying, and trips to the compost site with leaves and grass clippings. Less time, energy, and money is spent on maintenance and time is gained for backyard butterfly or bird watching, or other activities.

When designing a sustainable lakeside landscape, information is needed about the lot and adjacent lakeshore, including water runoff patterns, so that erosion can be prevented and water quality improved. Microhabitats must be identified so that suitable plants can be chosen and adequate numbers of plants can be grown or ordered. The ordinary high water level of the lake must also be determined since Minnesota Department of Natural Resources regulations apply to areas below this level. All this information can be organized and summarized into a plan based on your needs and preferred property uses. If desired, there are landscape design firms which can be hired to help develop plans.

The Minnesota Department of Natural Resources has an excellent book on landscaping, Lakescaping for Wildlife and Water Quality, by Carrol L. Henderson, Carolyn J. Dindorf, and Fred J. Rozumalski. Ordering information can be obtained from the Gift Shop (651-228-9165) or Minnesota's Bookstore (651-297-3000).

Landscape plan with buffer strip. Used with permission
of Fred Rozumalski, design and Reseanne Esparza, drawing.

Planning to complement activities

Landscape to complement your activities. For example, if a large lawn is not needed, parts of an existing lawn can be replaced with ground covers, perennials or shrubs. Note areas where views may be enhanced or screened with vegetation. Do not disturb areas with natural vegetation. Plan to install bird feeders and bird houses and benches to sit on to enjoy the view.

Accessories in the landscape are signs of a cared for and well-managed property. These elements of care show neighbors that the property is not neglected, and they are especially valuable in unconventional landscapes.

Correcting and avoiding erosion problems

Storm water management needs attention since water carries soil into the lake and cuts gullies. If serious erosion problems are developing, seek the advice of your watershed district, or county extension specialists.

Some erosion can be reduced by proper landscaping. Tour your property during heavy rain to observe runoff patterns. Work with your natural topography, and keep water quality in mind.

Steep slopes need careful planting to control erosion. Gardens should not be located on steep slopes unless the area is terraced perpendicular to the slope. Paths on the shore from house to water line should run diagonally rather than straight down a hill. Eroded paths should be replaced with steps. Hard surfaces that allow water to run off should be replaced with porous surfaces such as gravel or mulch.

Selecting plants

Native plants are hardy, do not require fertilizer once established, and provide food and habitat for native animals. Most native species are perennial, and they also maintain themselves by reseeding on the same site. In contrast, popular bedding plants such as petunias and geraniums often provide little value for wildlife and must be replanted each year.

Though many exotic perennials can be adapted to local climates, they may not be as valuable in supporting beneficial insects such as predators, pollinators, and butterflies. Horticultural varieties of native plants, which could also be used, have been altered in ways that reduce their value as food to animals. For instance, double flowers provide little nectar to butterflies, bees, and beneficial insects.

It is also important to know that the use of some exotic plant species is illegal. Buckthorn and purple loose-strife, for example, are exotic plants that escaped from cultivation and have become serious pests in natural areas.

Identifying microhabitats or zones

Habitats within the landscape need to be identified based on light and moisture regimes so that proper plant species can be added to each such microhabitat. Dry, sunny locations support prairie vegetation, while areas under trees are preferred by shade-tolerant species. Places with wet soils support wet meadow vegetation. An emergent zone is an area of shallow water. And a submerged, floating leaf zone, supports plants that grow through the water column to the surface.

Four specific zones are defined:

• Zone 1: prairie if sunny, or woodland if shady
• Zone 2: wet meadow, wet soil
• Zone 3: emergent, shallow water
• Zone 4: submerged, aquatic, with soil that is never exposed

Plants must be selected which are suitable for a location, and suitability is based on actual observations of soil moisture and sun or shade conditions. Some recommended species are listed in Table 1 and Table 2. A more comprehensive and extensive native plant list begins on page 13.

Table 1. A brief list of plants found in upland, wet meadow, emergent, and submerged zones.

Trees and shrubs can provide shade, frame your view, and hold soils on steep slopes. Grasses, sedges and flowering perennials can be used where an unobscured view is important.

Identifying the lake boundary

You need to locate the ordinary high water level of any body of water where you seek to landscape a shoreline. This is considered to be the highest water level that the lake has maintained for enough time to leave evidence on the landscape.

The high water level is considered to be the legal boundary of the lake bed. It is often the highest point reached by emergent plant species such as sedges, rushes, and cattails. The Minnesota Department of Natural Resources has jurisdiction over all areas below that ordinary high water level. A permit from the DNR is required to remove or add any plants in this area. Plantings above the ordinary high water level are subject to local ordinances, if any exist.

Using a buffer strip of vegetation

Buffer strips are natural unmowed areas between the water's edge and a lawn or hard surface such as a driveway or patio. Runoff will pass through the buffer strip to reach the water, but its speed will be reduced and much of the sediment it carries will be captured by the buffer strip.

A buffer strip should be at least 30 feet deep, reaching up the slope from the water's edge and extending as far as possible along the shoreline. For example, if you have 100 feet of shoreline, you should reserve 25 feet or less of shoreline for lake access, and convert the remainder to buffer. Wider buffer strips will be even more beneficial. Even simply leaving a strip unmowed will allow the growth of taller and denser plants which will slow down runoff and intercept sediment.

The use of native plants will make buffer strips more attractive and increase the area's biodiversity. The most effective buffer strips consist of vegetation with dense root systems and many erect stems which persist through fall and spring rains. Multiple layers of trees and shrubs are most effective against soil erosion on steep slopes.

Buffer strips along lake margins have also been demonstrated to reduce access by geese to lawns. The University of Minnesota's Department of Fish and Wildlife website has more information on this subject (www.fw.umn.edu/extension/indept.html).

Table 2. Some common native plants.

Solidago species goldenrod prairie	Aster Novae-anglia New England aster prairie	Ratabida pinnata gray-headed coneflower prairie	Veronicastrum virginicum Culver's root prairie	Liatris species blazing star prairie
Monarda fistulosa wild bergamot prairie	Andropogon gerardii big bluestem prairie	Verononia fasciculata ironweed prairie	Iris verisicolor blue flag iris wet meadow	Lobelia cardinalis cardinal flower wet meadow
Carex comosa bottlebrush sedge wet meadow	Pontederia cordata pickerel weed emergent	Sparganium americanum bur-reed emergent	Alisma plantago-aquatica warter plaintain emergent	Sagitaria latifolia arrowhead emergent
Typha latifolia cattail emergent	Nymphae odorata white waterlily submergent	Valisneria american wild celery submergent/floating leaf	Nelumbo lutea American lotus (protected specie) submergent/floating leaf

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