No matter what we do, they’re always there to interrupt our fun. We’ve made them feel unwelcome, but still they keep coming-in bigger and bigger numbers all the time. We know we’ll never truly be rid of them, but we sure don’t want to give up and get used to them. Weeds. The garden equivalent of long-distance phone service salespeople.
A weed is, of course, any plant that grows where it’s not wanted. In the lawn, weeds are easy to identify, because they’re anything that isn’t a blade of grass. Lawn-owners who want to be rid of weeds can buy any of a number of herbicides designed to be selective about what they kill, leaving the lawn grass alone. In flower, vegetable or shrub plantings, though, it’s not so easy-particularly early in the growing season, when the weedlings may look as promising as the seedlings.
Even though it’s not possible to buy a selective herbicide for a planted bed-a product that would kill everything but impatiens, for instance-controlling weeds in those areas is a straightforward process. Find them, get them out, and reduce the opportunity for them to come back.
Finding them is sometimes easy. In a thicket of hostas, anything else is a weed and has to go. Sometimes it’s harder than that-in a bed that mixes several plant varieties, say, or one in which a previous owner of your house did all the planting and you arrive not knowing which green things were intended and which weren’t.
Literally hundreds of varieties of weeds afflict Chicago-area gardens. Some are well-known, such as dandelions. Some are familiar in other contexts: A cultivated plant that drops its seed all over the yard may send up dozens of new plants next spring. Encouraging them might seem like a handy source of cheap plants, but in some cases it defeats the purpose.
Store-bought annuals, for instance, get a jump-start on the short Chicago growing season in greenhouses or warmer climates. Their pups grown in the yard from seed may just be getting big enough to flower when fall frosts kill them. Also, many varieties don’t grow true again from seed. A dwarf cultivar of Shasta daisies that grows just 10 inches tall can generate seeds that sprout into adult plants two feet high.
A simple tip for making weed identification easy in newly planted beds comes from James Ethridge, who chairs the ornamental horticulture department at Joliet Junior College: Insert the little name tag that comes with each plant next to its owner. “That way, you have a little reminder. `This is not a weed. Don’t pull it out.’ “
Beyond that, Ethridge says, weed identification is a tough field. Once they’re knee high and waving their weedy little limbs over the petunias, some weeds are pretty noticeable. They may be more inconspicuous as babies, though. Many weeds look completely different when they’re young than when mature-and some are dead ringers for desirable plants. Silvery cinquefoil looks like a slightly rangy cousin of delphinium. It’s only when they bloom, one a glorious flutter of blue, the other a pedestrian yellow circle, that the difference becomes glaringly obvious.
“In school I had to learn to recognize 300 to 400 weeds at their seedling stage,” Ethridge recalls. “I don’t think most homeowners are going to want to do that.”
The University of Illinois Cooperative Extension Service publishes several books and pamphlets that have pictures of common local weeds. The most comprehensive is the 303-page “Weeds of the North Central States,” which the extension sells for $5, plus postage. Other titles include “Lawn Weeds and Their Control” ($2), “Pesky Plants” ($5), and “Vine Weeds of the North Central States” (first copy free, 50 cents thereafter). Call 312-737-1178 to order a copy of any of these publications.
“Weeds of the North Central States” is like a portable post-office wall filled with hand-drawn mug shots of more than 200 garden criminals. It includes notorious weeds like pigweed, lamb’s quarters and mouse ears, as well as less known thugs such as devil’s beggarticks and fragrant cudweed. For gardeners who frequently wonder whether a certain green thing in the yard is a weed or a friend, “Weeds of the North Central States” is a handy companion to keep nearby while gardening. Finding a weed in it can be time-consuming, but once identified, that weed will be easier to manage.
Still wondering if something is a weed? Some extension offices have weed-identification experts on staff. (Ask the telephone operator for the local office of the University of Illinois Cooperative Extension Service.) Some even accept unidentified plants through the mail.
Getting weeds while they’re young is a crucial part of managing them. An old gardening adage says that one weed pulled today is 10 weeds you won’t have to pull tomorrow. Some weeds are so prolific they can spawn several generations in one growing season. Blame it on evolution: “They reproduce fast because they know we’re going to attack them,” Ethridge says. “They want to preserve the species, so they put a lot of effort into creating offspring. That way, if we don’t kill the adults, it’s just more population for the species.” Clearly uprooting them before they have a chance to reproduce is a labor-saving device.
Bear in mind, too, that weeds are opportunistic. They know they won’t be pampered, so they send their roots tunneling deep for water. Often, the root can make up for having its above-ground plant lopped off by regenerating a new one-or several-so getting the roots is more important than simply doing the cosmetic work of eliminating the above-ground eyesore.
Garden centers sell a variety of hand tools designed to pry up a weed’s roots. In addition, experts advise two weeding techniques that get to the root of the weed. First, “Pull weeds when the ground is moist from rain or sprinklers,” says Ron Wolford, urban gardening educator for the extension. They are more inclined to slide out whole when there’s no hard, dry soil holding them down. Second, “Try to get them when they’re no taller than two inches,” Ethridge suggests. “Short weeds usually still have short roots.”
Snipping off the visible tops of weeds but leaving the stalks that are concealed by other plants just encourages them. “It’s like pinching a flowering plant,” Ethridge says. “You’re telling it to send out even more shoots.”
Commercial chemicals do the job, but they should be handled carefully. The most effective ones, like Roundup and Kleenup, are systemic, meaning they get into the plant’s internal systems and kill it from the inside. They’ll kill any plant that way, explains Brian Sager, an animal and plant science instructor at McHenry County College in Crystal Lake, so they have to be kept away from any desirable plant.
“It’s very important to closely control that spray bottle,” Sager says. “If the weeds and the plants you want to preserve are close together, it’s better to swab the stuff onto the weeds with a cloth so you can be sure you’re keeping it off the other plants.” Also, don’t use a weed-killer when a breeze is likely to carry the spray off to wreak havoc where it’s not needed, he says.
Sager and Ethridge both say that commercially available systemic herbicides are safe for the soil because they lose their potency soon after use. “The nice thing is, although it will kill whatever it comes in contact with, it is deactivated when it hits soil, so it doesn’t toxify the soil,” Sager says.
A smart way to cut down the number of weeds that get a foothold in planted beds is with the gardener’s all-purpose tool-mulch. Besides holding in ground moisture, cushioning the effects of the freeze-thaw cycle in winter, and making the bed look tidier, mulch also combats weeds. “A three- to four-inch layer of mulch will dramatically reduce, but not eliminate, weeds,” Wolford says. They simply can’t get through.
Landscape fabrics, which are designed to be laid atop the soil surface and only allow plants through where holes have been made for them, also reduce the weed survival rate, but Ethridge says the effect declines over time. “As dust and debris settle on top of the fabric over the years, they make it possible for weeds to take root on top of the fabric,” he says. “Still, you’ll have fewer weeds than without the fabric.”
It seems that no matter what form prevention takes, every garden will still have some weeds. “The No. 1 thing to do is get out there and pull them, stay on top of them,” Sager says. “Keep them at a manageable level so they don’t become an overwhelming problem.”
And through it all, keep a good attitude. As Ethridge notes, “Just keep thinking that pulling weeds is therapeutic-it’s a lot better to take out your frustrations on weeds than on your co-workers.” Or a tele-marketer.
