There's an old saw that goes like this: Do not follow where the path may lead; go instead where there is no path and leave a trail. While an admirable metaphor for business, this advice can ruin a good landscape design. Compacted soil is conducive to pedestrian use, not plant growth. Foot traffic destroys friable, aerated, well-drained soil that plants require to thrive.
A path will begin to form where only one person walks over the land. You may have seen this natural phenomenon where the mail carrier crosses your property, or where schoolchildren take a shortcut over your lawn. If such paths are taken regularly, plants grow smaller, less dense or not at all.
Paved walkways guide people along an approved route, one that's designed to protect plant life. They also define space, your space for relaxation and recreation and the plants' space for growing and blooming.
Before you determine the shape of a paved walkway, you must know how you want to use it.
Install a pattern of circulation that encourages meandering if you're interested in admiring the garden as you walk through it. A curved line, or "offset" sections of paving, have the effect of slowing movement, causing you to notice your surroundings. This path line would be appropriate for perennials, sculptures, water or other gardens that invite more than just a quick glance.
When designing a circulation line solely to accomplish chores, such as taking out trash, gardening, walking the dog or getting firewood, the walkway is better designed as a straight line. This invites rapid movement between points A and B.
Curves should look as if they're supposed to be there. Do this by placing a large plant, rock or sculptural feature where you must walk around it. Otherwise, human nature takes over, and people will not stay on a curved walk, favoring that shortest distance between two points, the straight line.
Proof of this can be found on university campuses. Older institutions have walkways that fit a quadrangle layout. But the "beaten paths" students take from class-to-class tend to be diagonal lines that slice the landscape into a network of the shortest possible routes between buildings.
A modern practice for architects is to design self-determining circulation patterns. They design buildings, then come back several months after the project has opened to check pedestrian circulation patterns. Paving is then designed and installed according to the paths that the people created. The people using the property show exactly where walks need to be placed. Your property may already show such signs.
Walks that lead to main entrances should be wide. Large houses can have walkways four to 10 feet wide to fit the proportion of the building. A straight path 50 feet or longer should be four or more feet wide just to fit the space comfortably.
The minimum width of a walkway is determined by basic needs. Average human shoulder width is 18 inches. Allowing an extra six inches, the walk should be a minimum of 24 inches wide for one person. It must be twice that wide if it must accommodate people walking in past one another at the same time. The minimum path size for people in wheelchairs is at least six inches wider than the vehicle itself, which generally is 36 inches in width; 60 inches may be sufficient for two-way wheelchair traffic. At fence, gate or door openings, the width for wheelchair access should be a minimum of 32 inches.
According to the Americans With Disabilities Act, maximum grade for wheelchair accessibility on walks and ramps is 5 percent. That means a wheelchair-accessible walkway should rise or drop no more than six inches per each 10 feet in length. At entrances, steps and tops of curbs, the grade should be reduced to a maximum of 2 percent.
For complete guidelines on accessibility for disabled individuals, call 1-800-514-0301 or 1-800-514-0383 (TTY). An excellent text on the subject is "The Enabling Garden," by Gene Rothert (Taylor Publishing, 1994, $12.95).
You can also separate plants and people, and greatly enhance comfort in your garden, by designing seating along with walkways. Any object that you can comfortably sit on is appropriate to consider. A good spot to place seating is where paths cross, given the human tendency to hesitate there, or where one type of paving meets another.
There are too many types of seats on the market to enumerate. They exist in every configuration and material. Rocks, tree stumps, walls and planters can double as seating, so remember to consider this dual use when doing your initial design. The comfortable sitting height for most people is 17 to 20 inches, and the seat depth is 12 to 24 inches, depending on the use, if any, of cushions and back supports.
You will want your seating to blend with the walks. In addition to the old standards--brick, flagstone and concrete--there are new paving materials, including interlocking brick-size blocks, concrete in various colors and textures, pressure-treated lumber and gravel mixed with epoxy and laid like concrete. Call garden centers and paving supply companies to learn what's available.
The best book I have seen for idea development and installing paths is "Garden Paths," by Gordon Hayward (Camden House Publishing, 1993, $19.95).
Lerner is president of Environmental Design in Capitol View Park, Md. His e-mail address is email@example.com.