Weeds, according to Washington extension agent Mary Robson, are "the gardener's most persistent pest."¹ While pulling a few weeds on a pleasant spring afternoon can be a joy, many of us have far more weeds than we have time or patience for weeding.  But don't despair!  By planning ahead and staying on top of your weed problems you can keep weeds from taking over your shrub and flower beds without using pesticides.  Try a combination of the strategies in this article to keep your problems manageable.

Planning for Fewer Weeds

Designing your yard so that it doesn't encourage weeds can save you countless hours of weeding.  If you have an area in your yard that seems prone to weed problems, think about redesigning and replanting it to help reduce weeds.  Here are some ideas to consider:

• Plant well-adapted varieties; their vigorous growth means weeds affect them less.²
• Use headers -- wood, metal, or concrete dividers that are buried at least eight inches deep and stick up a couple of inches above the soil.  Headers are useful for separating lawn areas from shrub beds, so that the grass doesn't invade.  Low headers act as mow strips, allowing your mower to cut all the way to the edge of the lawn.²
• Use vigorous annual plants² or ground covers¹ to out-compete weeds.  There are many kinds of plants that work well this way.  You'll want to choose plants that thrive in the conditions of your yard.  Your local extension agent or master gardener can give you advice.

Preparing Shrub and Flower Beds for Planting

A little effort preparing your shrub and flower beds before you plant them can pay big dividends. One way to reduce future weed problems in your beds is to use repeated cycles of irrigation and cultivation.  Start by cultivating, then irrigate.  Wait about two weeks to allow weeds to germinate, then cultivate again to kill the new seedlings. Repeat at least twice.  Cultivations should be shallow so you're not bringing up seeds from deep in the soil.² Another useful technique is solarization. Solarization involves putting a transparent sheet of plastic over a tilled bed.  You should do it during the warmest, sunniest two months of the year.  The temperature under the plastic gets to be about 20 degrees warmer than normal soil and kills weed seeds.³

Mulches Solve Many Problems

One of the most commonly recommended weed management techniques is mulch.  Mulch can be either organic (bark, grass clippings, leaves, sawdust, wood chips, or pine needles) or synthetic (polyester landscape cloth).⁴ Before you spread your mulch, remove any existing weeds.  Organic mulches should be between two and four inches deep.⁴  Don't use hay for mulch unless it is composted; it contains lots of seeds.⁵ If you use a synthetic mulch, you might want to put an inch of organic mulch over it to improve its looks and to protect it from sunlight.⁴ In addition to keeping weed numbers down, mulching cools down hot summer soils, and keeps them from drying out.⁵  In the winter, mulches protect roots and insulate plants from the cold.⁶ One caution: Keep mulch away from the trunks of shrubs or trees.  It can encourage rot or mice.⁶

Don't Bring Weeds into Your Yard

It's possible to bring weed seeds into your yard if you bring in topsoil, plants in containers, mulch, or manure that is contaminated with weed seeds or roots.  You can also bring in weed seeds on garden equipment. Composting, soil pasteurization, and cleaning of tools will keep these problems to a minimum.²

Water and Fertilize Plants You Want, Not Your Weeds

Make sure that you're creating good growing conditions for the plants you want in your yard, not for the weeds. Excessive watering or fertilizing can encourage weeds.  Landscape shrubs don't usually need fertilizer unless you have a specific nutrient problem.² If you live in an area where irrigation is required during most of the year, you can minimize weed problems by using an irrigation system that targets water to the plants you're trying to grow.²  Try drip irrigation or soaker hoses.

Be Prompt

The best time to remove weeds from your shrub and flower beds is early in the growing season.  Do your best to remove weeds before they develop a strong root system or set seed.⁷

Pulling Weeds

Hand-pulling weeds may not be high technology, but it "is of great value in landscapes."²  For pulling to be effective, you'll want to remove as much of the root system as possible. To make this easier, irrigate the day before you plan to weed if soil is dry. A number of specialized weed-pulling tools are also available.²

Hoeing

Hoes are another time-tested tool for removing weeds.  They are most effective when they're used on small weeds.  "Take your hoe and skim just below the surface of the soil," writes Washington extension agent Holly Kennell.  "The roots of the little seedling weeds will be cut or will be exposed and the plants will dry up.⁸ The key to effective hoeing is keeping the tool sharp.  A file works well to sharpen a hoe; draw it across the edge of the hoe in one direction until the blade is sharp.⁸

Weed Trimmers

If you have grass growing around your shrubs, you may find that a weed trimmer (string trimmer) is useful for mowing the grass.  You'll want to make sure that you don't damage the trunks of desirable plants.  You can put a simple homemade shield (made out of a short length of drain tubing split lengthwise, for example) around small trunks while you trim.²

Using Heat to Kill Weeds

Flame weeders (often called flamers) and radiant heat weeders use heat to control weeds.  You might find them useful if you have a fence near your beds, for example, or pavement.² Flame weeders, fueled by propane, kill weeds after a brief contact raises the temperature high enough to disrupt the weed's cells.  Actually burning the plant is not necessary.² Radiant heat weeders use the same basic principles as flame weeders, but don't have an open flame. Fire, and even radiant heat, can be a serious issue when being used as a weeding tool.  Be sure that you take appropriate precautions.²

Reasons Not to Use Herbicides

If you're tempted to use an herbicide in your shrub and flower beds, consider the practical advice of Washington State University Extension.  "Herbicides have several disadvantages:

• They are expensive.
• They are difficult to apply with accuracy.
• Drifting or leaching may occur and damage desirable plants."⁷

By using the pesticide-free techniques summarized here, you can avoid these problems and keep your weed problems manageable.