The Green Scene

Dangers That Can Lurk in Your Landscape

Don't place large shrubs or tall walls in the line of vision at your driveway exit.
Don't place large shrubs or tall walls in the line of vision at your driveway exit. (Sandra Leavitt Lerner for The Washington Post)
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By Joel M. Lerner
Saturday, May 2, 2009

Most people consider gardens and landscapes fairly safe spaces except for the patches of poison ivy you weren't paying attention to or the tick habitats here and there. But, unless safety considerations have been taken into account, the landscape can be an extremely dangerous place.

Here are some proper practices:

Don't place large shrubs or tall walls in your line of vision where seeing pedestrians is necessary. Plan for visibility when pulling out to the street from your driveway. Keep clear lines of vision for several hundred feet where you intersect thoroughfares. If you want to screen your property, design walls or screening shrubs so that your car is past them before you reach the sidewalk or street.

Texture on walking surfaces must provide traction even when wet. Concrete can have a broom finish for traction; brick and flagstone should have a rough texture. Most concrete pavers available at home improvement and garden centers have a rough finish for good traction. If you seal asphalt, be careful that the material you use penetrates and doesn't stay on top, where it would make a slick surface. Sealants applied in a spray by installers are better than those that you buy and apply with a roller.

Illuminate walking surfaces. Very low lights, 15 or 20 watts, aimed onto paving and not directed at your eyes, will offer lots of visibility without ruining the ambiance.

Steps are one of the trickiest landscape elements to negotiate, usually because they are incorrectly designed. They should not be built too steeply. We have a different gait outdoors, and stairs should be more expansive to accommodate that. The absolute maximum riser height (vertical rise) per step should be six inches, and the tread size (stepping surface) should never be less than 14 inches. Many outdoor stairways tend to be built using steep indoor measurements (eight-inch risers and 10-inch treads).

Illuminate steps from above, and never have just a single step in your landscape. Design professionals call this a "trip step." A flight of stairs in your garden shouldn't have more than 10 steps without a landing. A 31- to 32-inch high railing should be installed along steps.

All water features demand additional attention regarding outdoor safety. A person can drown in a small amount of water, and children are particularly attracted to it. Make sure you locate ponds or swimming pools in a place where people are not likely to stumble or wander in when you aren't there. Regulations might require installation of a fence and locked gate. Call your local government to learn the zoning or regulations in your area for private water gardens or swimming pools.

Lighting water entails another set of safety considerations. Mixing electricity and water can be dangerous. Be sure to use only UL-approved equipment. The installer's electrician usually wires swimming pool lights directly into a 110-volt line. Install recessed lighting fixtures in swimming pools. Place grills or grates over the fixtures so debris and swimmers do not damage them.

The safest way for you to illuminate a lily pool, fountain or waterfall is by plugging a transformer into a receptacle and using low-voltage (12 volt) lights. Always plug into a ground fault circuit interrupter receptacle, called a GFCI, that was installed by a licensed electrician.

Even though low voltage is perfectly safe to work with, install your wire connections outside the water whenever possible. Another warning for water gardeners is to not use copper lights underwater because their copper sulfate corrosion is toxic to fish.

Given the high consciousness today for the safe use of insecticides, herbicides, fungicides and other chemicals, look for bio-rational alternatives that are safer and more environmentally friendly than many synthetic materials. Remember, they're still chemicals. If you're applying them yourself, you'll want two sprayers to avoid damaging your plants. Use one for total brush killers (non-selective herbicides), and another for lawn weed killers, fertilizers and insecticides.

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