No garden is ever going to be weed-free for long and all gardens require tending. The objective is to reduce the labor and time involved in battling uninvited ‘weeds’ and allow more fun time for tending the plants we want and love.
There are three basic ways to deal with weeds, not necessarily exclusive: herbicides, starvation, and manually pulling.
Herbicides are effective but are also the least desirable method. Extreme care should be used in choosing the correct herbicide for the problem. Always follow instructions, don’t spray on a windy day, never use near a water course, always wear protective gear, avoid use where children and pets are likely, and be super careful of the plants you want to save. In most cases, the risks and potential environmental harm far outweigh the benefits. Vinegar, salt, and boiling water are some examples of environmentally safer weed killers, but can still damage and kill garden plants.
The weed control method of starvation deprives the weed of what every plant needs: water, sunlight, nutrients, and space, which are resources we reserve for our chosen plants. However, it can frequently take as much as 3 years to eradicate an established stand of some invasive species such as knotweed or bamboo. The most used method of starvation is mulching. There are many mulch materials available: wood chips, compost, stones, cocoa bean hulls, grass clippings, and straw, to name a few. Each offers advantages and disadvantages regarding cost, ease of application, durability, appearance, and safety. Stone is certainly durable but expensive and very difficult to weed. Cocoa beans are expensive, if available, and toxic to pets. Grass, straw, and sawdust may be free on occasion but can cause more harm than good if they are wet and form an impervious barrier that impedes the flow of water. Wood chips are the most commonly used type of mulch and come in two grades: single and double shred. Single shred last longer but has a coarser appearance. Be sure when buying any garden product that it is guaranteed weed free. The latest concern is that commercial bulk mulch may be a source of ‘jumping worms’, a non-native, invasive earthworm that is devastating to the non-invasive earthworm and the environment and has no predators. Another method of starvation is a three-time annual mowing or cutting of the weed at ground level. Memorial Day, July 4th, and Labor Day are easy times to remember.
Manually pulling weeds is effective but labor-intensive and time-consuming although almost always necessary to some extent. It is best employed in conjunction with starvation techniques. Keep your tools clean. Weed seeds and other pathogens can be transported from one area of the garden to another on dirty tools. The same goes for gloves and boots.
The best defense is an offense
Weed control ideally begins well in advance of the garden’s creation by mowing or weed whacking the garden-to-be area, then laying a layer of corrugated cardboard over the surface (Cardboard has the advantages of being free, recycling a product that would otherwise be discarded and providing nutrients as it rots.) Anchor the cardboard with rocks or bricks and cover it all with 3 inches of mulch to hide the cardboard and prevent water run-off. Ideally, this should be done in the fall before planting. The idea is to prevent seed germination by depriving the dormant seeds in the soil of sunlight so they will not germinate, or if they do, will not thrive. Weed seeds are amazingly resilient and can remain dormant in the soil for many years until the desired germination factors are present. At planting time position plants and clear a patch of mulch, cut a hole in the cardboard with a knife or hori hori tool, and position your plant in the hole, replacing the mulch around the plant. The cardboard will take a year or more to rot, preventing most weed germination while your garden becomes established. Those weeds that do manage to germinate in the mulch layer are easy to pull.
An ounce of prevention
Mowing your lawn on a regular basis keeps lawn weeds from setting seeds that will blow or scatter into your gardens or be blown there by a leaf blower wielding yard service. An established perimeter around your garden prevents lawn and your neighbor’s weeds from crawling into your garden space. A six-inch border of mulch or ground cover can create a weed-free zone to protect your garden and presents a pleasing visual delineation between the garden and its abutter.
Weed control in the established garden is a bit more difficult
Weeds will assume control of any piece of bare earth, so the object is to cover the ground. This can be accomplished with mulch: wood, stone, grass clippings, sawdust, cocoa bean hulls, or living mulch*, i.e. the garden plants themselves; anything that will provide competition and deprive potential weeds of the water, nutrients, space, and sunshine. Two to three inches of mulch placed around garden plants, but not touching their foliage, will eliminate bare ground and discourage weeds. Those that do come through the mulch should be easy to pull if caught soon after emergence. Combining mulch with proper watering techniques will reduce weeds even more. Water only the plants you love by placing a soaker hose around your plants and not applying water to germinated weed seeds in open areas of the garden.
When you must weed: Weed when it’s wet and dig when it’s dry
Weeds are much easier to pull when the soil is moist and digging them out at this time exposes more deep soil (and more weed seeds) to sunlight. This is a real do as I say, not as I do item. Pull weeds as soon as you see them. This means an almost daily tour of your garden is beneficial for the garden and gardener alike because weeding is easier, less soil is disturbed, there is less trauma to the garden plants, and the gardener has time to enjoy the garden and doesn’t exhaust him/herself with a week or more worth of weed pulling and several hours of commitment. Don’t procrastinate. A matter of a day or two can see a weed grow exponentially and go from bud to seed. When doing a major weeding project, tackle just a small area at a time, stay in the shade, and use a kneeling pad or kneeler with handles to protect your knees. The kneelers have an added advantage because the kneeling pad is raised a few inches off the ground permitting use right in the garden without crushing the plants beneath it. Finally, always wear gloves! Thorns, twigs, or bits of glass can cause needless injury. You never know when you will come upon a poison ivy seedling courtesy of the birds or some other allergen or, my biggest ugh, a garden slug. When weeding, carry a bucket and place pulled weeds in it. Then, when the weeding session is complete, immediately empty the bucket into the trash, not into the compost pile. Weed seeds seem to continue to mature to viability even after the plant has been pulled and you don’t want them in your compost.
Knowledge is power: Know your weeds
Especially in spring, it can be difficult to tell the difference between emerging perennials, perennial seedlings, and weeds. A good reference book or phone app such as iNaturalist or PlantSnap is invaluable. Knowing if your weed is an annual vs perennial is important. Annuals grow only one season, set seed, and die. They also tend to create millions of seeds. Weeding out annuals before flowering is crucial to control not only this year but also for the future. Knowing when an annual germinates and flowers is the key to control. Perennials will die back to the roots in late fall but be back with a vengeance next spring. They multiply not only from seed but also by runner and sucker. It is important to remove ALL of the root system as well as the above-ground plant. Many, such as dandelion, dock, and evening primrose have deep taproots. Others like bindweed, chameleon plant, and Scottish harebells have running roots. Even a small portion of either root will start a new plant. Control of persistent perennial weeds is best accomplished with a dual attack using manual pulling and starvation by repeated cutting or pulling. Biennials have a two-year lifespan, usually not flowering until the second year. What you eradicate in year one won’t be there in year two.