Designing Your Conservation Landscape

Landscaping - handdrawn Garden plan of modern small City Garden

(Excerpted from Ecoscaping Back to the Future…Restoring Chesapeake Landscapes.)

“The supreme accomplishment is to blur the line between work and play.” –Arnold Toynbee, British Historian

“Gardening is an educational process that lasts a lifetime. Its diploma consists of a green thumb, a happy heart and a permanently enlarged soul. If you’re ready for an advanced degree, Mother Nature is anxious to teach. Her class is always in session.” –Author Unknown

WHERE TO BEGIN?

“Plan your work, then work your plan” is a familiar saying and good advice that bears repeating, especially to gardeners. Alexander Pope wrote, “All gardening is landscape painting.” Before you begin your masterpiece, reduce it to paper. When developing your design, consider such matters as site conditions, your own tastes, your impacts on the landscape, and how to improve same. It’s been said, “Thoughtful preparation will pay more dividends than a wheelbarrow full of fertilizer.” So remember, plan your work, then work your plants.


OBTAINING AND CREATING A SITE MAP

When starting on your home landscape or community project, it is important to first obtain or create a map of the site as it currently exists so that you will know what you have to work with. This will enable you to plan appropriately and to minimize unnecessary work, expense, and other problems. You can use a copy of a tax map, a topographic map of the area, or survey of the property; or you can create your own site map by taking measurements of the area. Transfer the measurements onto a piece of graph paper to produce a scale base map. The scale of landscape maps and drawings are usually 1/4 inch equals one foot, 1/8 inch equals one foot, or 1/16 inch equals one foot.

Then add to your scale base map permanent features that exist on the site, such as buildings, accessory structures, walkways, lights, water sources, utility right-of-ways (sewer, septic, water, etc.), and existing beneficial plants. Remember to consistently use the same symbols throughout the drawing; for example, use one symbol per type of plant. Feel free to make up symbols or copy ones you have seen on plans (there are no set standards). Add a reference key to indicate what the symbols stand for.

A good way to unleash your creative energy and not worry about your drawing ability or unnecessarily redrawing your scale base map is to create an overlay map, which can be created on tracing paper placed over the base map. Scale overlay maps are good for creative experimentation as well as indicating, for example, drainage problem areas or existing micro-climates. Areas of shade, surface depressions with moist soil, wind tunnels or slopes can form a microclimate worth noting on your map.


GATHERING INPUT

With maps of your site in hand, gather input from observation and discussion with family members, school or group members, and others sharing the landscape. Take time to walk through the landscape several times to study it and recognize the possibilities for the site. Give yourself time and enjoy the creative process.

Site considerations:

  • Climate
  • Topography
  • Soil type (moist, wet, dry, loam, clay, sand, acid, or alkaline).
  • Light conditions for planting areas (full sun, or full to partial shade).
  • Water sources, including access to water for newly installed plants.
  • Existing vegetation and animals, including insects.
  • Past land use (e.g., debris may have been landfilled in an area).
  • Human-made structures (buildings, decks, patios, sidewalks, fences, util
ity rights-of-way, etc.).
  • Traffic patterns of people in vehicles and on foot, including sports and 
play areas; traffic patterns of wildlife.

Some of the questions you may consider are:

What are the practical uses of the site? What about service areas, for example, garbage cans, workspace, clotheslines, and storage? Is recreation space for people as well as pets needed? Will portions of the current landscape be retained? What species of wildlife do you want to attract to the landscape? Will there be a vegetable garden? How will maintenance be handled? Are there local ordinances to consider?

Now is also a good time to take a soil sample of the areas to be planted. A soil test kit can be obtained from your local county extension office (check the blue pages of your telephone directory), or from garden supply centers. Knowing the soil characteristics of the designated planting areas is important to select appropriate plants for the site.

Remember, the evaluation process will be ongoing, just as a garden is a growing, living thing and is never complete. As well, nature may decide—independent of your ideas—to edit your landscape. With these considerations in mind, sketch out your desired results. Modify your plans and ideas as needed.


DEVELOPING A GARDEN DESIGN

“I have never had so many good ideas day after day as when I work in the garden.” –John Erskine

Conservation landscape design is the arrangement of plants, water features, stone, accessory features, and the working with or creating of contours in
a landscape to enhance it for our use, enjoyment, wildlife needs, and the overall health of the environment. A good design will unify the landscape as a whole.

A good starting place in developing your design is to take or collect photographs of the natural areas that inspire you. Use these for ideas to change your traditional landscape into one that is more environmentally friendly. Photos can provide helpful design ideas for your project. Also, it is very instructive to take before, intermediate, and after photos of your landscape project.

After gathering input, you are ready to begin designing your garden. There is more than one approach to landscape design; however, imitating nature’s designs—arrangements, patterns, colors, and textures found in nature—can provide the best results. The following guidelines will facilitate the design process.

Basic principles of design to keep in mind:

  • You may find it helpful to begin with the shape of your design. Consider a variety of curvilinear forms. For example, create a sun-shaped area for a raised xeriscape (drought tolerant) planting bed. Work with or create contours in the landscape, for example, swales for rain gardens. For a naturalistic garden effect, remember that nature tends to design in curves, rather than straight lines.
  • Consider emphasizing natural features in your yard, such as existing trees, swales, and depressions, to create a rain garden or a pond, or dry areas to create a xeriscape garden.
  • Place plants in appropriate growing conditions. Vegetation will grow and thrive if you plant the right plant in the right place. For example, a plant that requires dry soil and sun won’t thrive in a wet, shady location, and vice versa. Know the site conditions and research the plants you wish to use.
  • Research your plants to become familiar with their mature size;
leaf structure; bloom color, shape, time of year, and duration; wildlife benefits; and look throughout the season, such as whether selected plants are evergreen or not.
  • Plant in drifts (massing of like plants). For example, drifts of the same plant strategically located within a meadow (which is a varied mixture of native grasses and wildflowers) can create dramatic effects.
  • Consider the needs of wildlife—water, food, shelter, and space—the ingredients necessary in the landscape to support and attract wildlife. A 
wide variety of plants in the landscape will attract the most species by providing these necessary elements. The spatial arrangement of food, water and cover is important, both to attract wildlife and to decrease competition among species. When planning your habitat garden, connect planting beds to create wildlife corridors where possible. Corridors provide areas in which wildlife can safely travel to meet their needs.
  • Consider layering your plant arrangements. For example, create a gradual transition from grasses and wildflowers to shrubs to under-story trees to canopy trees for a more natural look and greater wildlife benefits. Varied layers provide a range of light, temperature, food, nesting, and hiding areas for wildlife.
  • Plan your garden with seasonal changes in mind. For example, in addition to spring-blooming plants, consider four-season gardening by adding summer- and fall-blooming plants, as well as plants that have winter interest.
  • Even a small garden can benefit from adding a path. Paths help direct traffic, facilitate maintenance of the garden, and can enhance the design and use of the garden. Consider the traffic flow through the property. You can direct people where you want them to go, or not go, by your path placement; but also take notice of the paths people naturally create. It generally works better to go with the flow. Various types of mulch make a good surface for paths; and don’t forget to control weeds by adding an underlying layer of weed-blocker fabric, newspaper, or cardboard.

“Paths lead us to the center, converging, reestablishing the familiar. Paths lead us away, far from the familiar, into adventure, into change. A good path is irresistible.” –Mary McCoy

CREATE A GARDEN PLAN

Take your site map—keeping the principles of design in mind—and sketch in the location of plants, paths, and other elements for the entire site. This will also help you phase in the project in stages if you can’t accomplish it all at once. Use either tracing paper and pencil, or grease pencil and clear plastic. Place the tracing paper or plastic over the base map. Begin by designating the human elements to include from your input-gathering exercise, such as recreation areas or a vegetable garden; then begin defining shapes, placing trees, shrubs, and herbaceous perennials, stone, and special features. Sketch possible natural elements you wish to enhance, such as a swale for a rain garden. As you add plants to your sketch, remember to use consistent symbols and make a reference chart for the symbols.


SITE PREPARATION

Site preparation varies widely depending on circumstances. It can be quick and simple, especially if you have the help of heavy machinery such as a bobcat, or it can sometimes take more time and effort than planting the garden. Before you dig in any area, it is critically important that you call Miss Utility (1-800-257-7777, from 7 AM to 5 PM unless it is an emergency, in MD, DE, and DC) no less than (and preferably more than) two business days ahead to locate any underground service lines or utilities that may be located where you intend to plant. Miss Utility will make all of the arrangements with utility, cable, and phone companies to mark designated areas with different colored paint (which will last through a few rainfalls) to indicate whatever utilities may happen to be in the planting area. Their automated phone system is easy to use and explains the color coding. If you don’t see any markings after making arrangements with Miss Utility, you should double check with them to be sure there are no lines in the designated planting areas. Planting where lines are located is not prohibited, but you are required to dig by hand in these areas. Use caution; you don’t want to accidentally dig up your phone line, and there may be restrictions to activities in rights-of-way.

In some cases, you will need to clear the area of turf and debris. Check the soil for obstructions such as asphalt, large rocks, or problematic soil texture (e.g., heavy clay or excessive compaction). Turf grass can be removed by hand, with a sod cutter or bobcat, or it will need to be covered for a few months until it is fully dead. If your planting date is a few months away, a convenient way to eliminate turf is to smother it by covering it with either cardboard or layers of newspaper. Add a 3- to 4-inch layer of wood chips or shredded pine mulch on top of either paper product to help hold it in place and create a planting bed (be sure to completely cover all of the grass). In approximately four or more months the vegetation will have died and the cardboard or newspaper will be decomposed enough to easily plant through it.


SOIL

“Babylon died because its soil died.” 
–The Nashville Tennessean

Soil is made up of sand, silt, clay (which are large, medium, and very small rock particles, respectively), and organic matter, in varying proportions. If there is too much clay or silt, the soil tends to become compacted, making it difficult for air, water and roots to penetrate; while too much sand compromises the soil’s ability to retain water and nutrients. Good, workable garden soil consists of airy crumbs in which particles of sand, silt, and clay are held together by decayed organic matter. The organic matter is the decomposed remains of once living things that now provide nutrients for growing plants, as well as improve the structure and texture of the soil.

Soils vary in “pH” rating (the acidity or alkalinity of soil), fertility, and drainage. A pH of 7.0 is neutral. Below 7.0 is acid, and above 7.0 is alkaline. Generally, it is best to install a garden suitable to the conditions you already have. However, plant selection may be limited if your site has very sandy soil, heavy clay, compacted soil, or extreme soil pH (below 5.5 or above 6.8). In these cases, you may want to seek expert advice. Determine the kind of soil you are working with by testing the soil where you plan to install your garden. Do a physical examination of the soil texture and density. Dig down about 6 inches to where the roots will be growing, and pick up a chunk of soil and squeeze it in your hand. If it sticks together and can be squeezed into a long ribbon, it may be heavy with clay which may need to be amended with compost. Classic garden soil has a relatively even mixture of sand, silt, and clay, with a bit less of the clay than the other two. Fortunately, many native plants are able to survive in a range of soil textures. Figure out what type of soil you have, and try to match it with the plants that will do well there.

Soil is often damaged through compaction and excessive use of fertilizers. A well-drained soil—generally defined as soil that can absorb 1/2 inch of water or more per hour—creates a good environment for native plants to develop deep roots and take advantage of deep water and nutrients. In the long run this makes for healthy, steady growth. You can test your soil’s infiltration rate by digging a hole 1 foot wide and 1 foot deep; next, pour a bucket of water into it and see how long it takes to soak in. If 1/2 inch or more of water absorbs within an hour, drainage should be adequate. If it takes much longer than that, you may need to amend the soil to improve infiltration.

If needed, the addition of the proper soil amendment can either help soil drain faster or slower. Well-composted organic material is an ideal amendment that can improve soil containing too much sand or clay. Compost improves soil texture and fertility by supplying organic matter. It provides a source of slow release nutrients for plants which encourages healthy, balanced growth, thereby reducing disease and pests as well as pruning maintenance. Composting also makes great use of excess yard waste.

Tilling is often unnecessary and can stir up dormant weed seeds. However, if amending the soil is necessary to effectively enhance soil properties, thoroughly blend either compost, topsoil, sand, or combinations of two or three amendments into the planting bed to improve drainage and promote even growth. In the case of rain gardens, if your soil is sandy, simply mix in compost to prepare for planting. If your soil is clay, you may need to remove and replace it with a recommended mixture of 50-60% sand, 20- 30% topsoil, and 20-30% compost. (Hint: Don’t worry about exact ratios. Proportions may vary based on the heaviness of the clay).

Amend the soil only if necessary. If you are landscaping with native plants, this step may not be necessary. Remember, native plants are adapted to local soil conditions (provided the local soil has not been significantly degraded or changed). Many native plants prefer not to have soil that is too rich.

Once planted, the garden should be dressed with a layer of composted mulch such as shredded or chipped pine to a 2- to 3-inch depth.


CHOOSING AND PURCHASING PLANTS

To develop a feasible garden design it is important to select the appropriate plants for the conditions of your site. Take time to research which plants are native to your area and will be appropriate for your site conditions. You may want to check online to find nurseries that sell native plants, and then take your plan to a nursery to seek their advice. It helps to have some flexibility in your plan since certain species may not be readily available.

Select plants with consideration to: their mature size and shape; leaf appearance; whether they are evergreen or deciduous; bloom structure, color, time of year, and length; seasonal interest; wildlife value; and features such as erosion control and other restoration landscaping values (some of which are covered in the following two chapters). When installing landscapes, common mistakes include planting young trees and shrubs, which will eventually become large, too close to the house or other structures, and planting trees, shrubs, and herbaceous perennials too close together. Consider the mature height of selected plants and how their size will affect your view. Some prairie perennials can grow ten feet tall, which may or may not be a feature you want to include.

A word about those pesky Latin plant names

Gardeners not trained in biology are often thrown off by the “scientific” Latin names for plants. They are, however, very useful for figuring out exactly what plant you are talking about. Think of them as a “first name” and a “last name,” which correspond to the genus and species. Using them allows you to discuss a particular plant with a nursery, another gardener, or someone from another part of the world, with certainty that you are talking about the same plant.

However, names change: “Taxonomists seem to love to mess with plant names. Now that plants can be identified right down to their chromosomes, many have turned out to be something other than they [were] thought to be. Just when you get proud of yourself for remembering the name of sweet autumn clematis, Clematis paniculata; it gets changed to C. maximowicziana, and there is word that this plant may get another name change.” –Ken Druse, The Collector’s Garden

Often the species name is descriptive of the plant in some way, and sometimes the Latin or Greek root gives you a clue in remembering the name. The species name may describe the plant’s color, shape, growth habit, or even a place name like americana or canadensis. For example, Acer rubrum, is red maple. The maples belong to the genus Acer; and this species is rubrum, Latin for red. Sugar maple is Acer saccarum, with saccarum from the Greek word for sugar.

Advice on plant buying:

1) HOW MANY PLANTS TO BUY:

Most perennials are planted 1- to 3-feet on center. Determine the number of plants needed by first measuring the areas where each type of plant will be installed. Use the following formula for guidelines on how many plants to buy. Consider adding 10% to account for some attrition, or start by spacing plants slightly closer together for appearance. You can thin most perennials later, however, large shrubs and trees are not as easy to move.

Use this simple formula to calculate the number of plants needed for your design:


A = Area to be planted (total square feet)
D = Distance plants are spaced apart in feet
N = Number of plants needed

Distance plants are to be spaced apart guidelines:

  • For perennials, use D = 2 feet (use 1.5 feet for slow spreaders, 3 feet for faster spreaders)
  • For shrubs, use D = 5- to 7-feet (based on mature size)
  • For a mixture of trees and shrubs, use D = 10 feet for a naturalistic 
planting
  • For ornamental trees, use D = crown spread

Formula: A ÷ D2 = N

For example: If you decide to plant an entire 100 square foot area with perennials that are spaced 2 feet apart, then you will need 25 plants, or 100 feet ÷ 4 (2 feet squared) = 25.

2) WHAT COMMON CATALOG SYMBOLS MEAN:

Not all nurseries use the same symbols for plant needs. Be sure to check the catalog. Many use symbols like those below quoted from Native Plants for Wildlife Habitat and Conservation Landscaping: Chesapeake Bay Watershed, by Britt E. Slattery, Kathryn Reshetiloff, and Susan M. Zwicker, published by the US Fish and Wildlife Service, Chesapeake Bay Field Office.

LIGHT: The amount of sunlight a plant requires is defined as: 1) Full sun (Su), the site is in direct sunlight for at least six hours a day during the growing season; (2) Partial shade (PS), the site receives approximately three to six hours of direct sunlight; and (3) Shade (Sh), the site receives less than three hours of direct sunlight or filtered light.

MOISTURE: The amount of soil moisture a plant requires is defined as:
(1) Wet (W), areas where the soil is saturated for much of the growing season, except in droughts. Many of the plants designated for wet areas tolerate specific ranges of water depths. Consult a wetland plant specialist or reference book; (2) Moist (M), areas where the soil is damp, and may be occasionally saturated (“average soil” has been included in this category); and (3) Dry (D), areas where water does not remain after a rain. The latter areas may be in full sun or in a windy location, on a steep slope, or have sandy soil. Plants in this category are drought tolerant and appropriate for a xeriscape garden. 

Additional details on plant buying and installation can be found in Chapter IV of Ecoscaping Back to the Future…Restoring Chesapeake Landscapes.