Weed Wrangling

Sustainably manage unwanted vegetation, and hold your own among the coffee shop weed wranglers.

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Next to “cash flow” – and the inevitable “cash flow problems” – one of the most popular topics of conversation at country coffee shops, feed mills and other popular rural gathering spots is weeds. It seems that having the biggest, baddest or most exotic weeds carries bragging rights that rival those for growing the earliest tomatoes, the biggest pumpkin or the best sweet corn.

Like death and taxes, weeds are something that all humans, but especially country residents, have in common. Maybe that’s because there are just so darn many weeds. 

Some 18,000 species of plants are native to North America, according to the National Park Service. For the longest time, that didn’t pose any problem. “Our native flora provide the foundation of the American landscape and define the various ecosystems and regions of the country,” the Park Service says. Plants and animals were free and content to live and let live. But then humans arrived on the scene, and everything started changing.

As we tired of simply hunting and gathering, plants that didn’t matter before suddenly became problems. Some 7,000 years before Europeans settled in North America, Native American women stirred the soil with digging sticks and hoes made of bone and wood to rid their corn, beans and squash of unwanted vegetation. These wild plants now competed with crop plants for moisture, nutrients and sunlight. 

“What is a weed?” asked 19th-century transcendental philosopher Ralph Waldo Emerson. “A plant whose virtues have not been discovered.” 

That may be, Ralphie, old pal. But until those virtues are discovered, weeds are a nightmare that costs American farmers and ranchers, gardeners and country folk more than $5 billion a year in lost yields and control measures.

“Control” is the word that most weed scientists use today to describe our war on weeds. “Management” is a close second. Forget the 1950s rhetoric of “winning the war on weeds.” Mother Nature has armed what we call “weeds” with enough chemical, biological and mechanical weapons to make the mightiest army despair. This awesome artillery ranges from armor- and tire-piercing thorns to skin-blistering poisons.

Weeds have a libido to make even the most amorous rabbits blush. A single pigweed plant routinely produces about 100,000 seeds. Then there is knapweed, a member of the sunflower family, which also includes dandelions and daisies. In only 10 years, the United States Bureau of Land Management estimates, just 100 spotted knapweed seeds can give birth to nearly 4.8 billion new plants that, in turn, produce almost 5.2 trillion new seeds. Leave one piece of purslane in the garden and it grows into a new plant. Roots magically shoot out of the stem of an uprooted galinsoga and burrow into the ground. While galinsoga (gallant soldier) is an indicator of fertile soil, most gardeners see it as a monster right out of Aliens or The Blob.

Many weeds are homegrown terrors. But in today’s mobile society, more and more weeds come from the far corners of the earth. No border fences or guards can stop them. “Legions of alien invaders are silently creeping into the United States and taking over our native plants and animals at an alarming rate,” warns Weeds Gone Wild, a project of the Washington, D.C.-based Alien Plant Working Group. “Invasive weeds are taking over 4,300 acres of public lands a day.”

The enemies’ names and nationalities are well-known: Asiatic sand sedge, Chinese lespedeza, English ivy, Eurasian watermilfoil, Japanese knotweed, Oriental bittersweet, Russian thistle, Siberian elm and Yellow Himalayan raspberry. Knapweed is native to southern Ukraine, Russia, Iran, Kazakhstan and Mongolia, yet 25 species of knapweed are found throughout the United States and Canada today.

“The first key to weed management is proper weed identification,” advises my Agronomy Guide from Pennsylvania State University’s Cooperative Extension, in University Park. The more you know about weeds and their growth habits, the easier it is to attack weeds at their weakest. Knowing your enemy can also keep you from creating even more of a weed problem. A rotary tiller, for example, is one of the worst things you can use against some weeds, since each chunk of chopped up thistle root, purslane and galinsoga can grow into a new plant. Check your local cooperative extension service office for the Agronomy Guide and Commercial Vegetable Production Recommendations for your state. Cost is about $10 each.

Certainly the most publicized – and advertised – weapon against weeds is herbicide. Using herbicides to control weeds requires learning a whole new vocabulary. These are some of the more common terms to describe how herbicides work and when to apply them: “Preemerge” (preplant) or “postemergence,” “selective,” and “nonselective” or “broad-spectrum.” Then there are “contact” and “systemic” herbicides, which either wither a weed on contact or poison a plant’s circulatory system.

They have macho-sounding names that chemical companies dreamed up to make you feel just plain good about zapping weeds with – Authority, Backdraft, Bicep, Broadstrike, Bullet, Cobra, Command, Crossbow, Eradicane, Extreme, Field Master, Fusillade DX, Guardsman, Harness, Hornet, Lasso, Liberty, Lightning, Marksman, Matrix, Ramrod, Raptor, Rodeo, Roundup, Pentagon, Prowl, Pursuit, Python, Scorpion III, Squadron, Steadfast, Strategy, Stinger, Touchdown, Valor, Ultra Blazer and Whip.

Even “organic herbicides” stress the deadly “cide” part of herbi-cide. A fast-acting weed and grass killer made of super-strong vinegar and lemon juice is called BurnOut. Corn gluten meal, an organic preemergence herbicide that inhibits root growth, is sold under a dozen different names, including Tiger by the Tail and Supressa. Corn gluten meal also contains 10 percent nitrogen, a powerful fertilizer, so it is labeled as a “weed and feed” product for turf, field crops and gardens.

“Granular” herbicides are “incorporated” (mixed) into the soil, prior to planting. “Wettable powders” and assorted liquids are applied with sprayers. They are mixed in the sprayer tank, which gives rise to the term “tank mix.” A simple backpack sprayer holds up to about five gallons. “Saddle tanks” mounted on the sides of a tractor can hold hundreds of gallons. Trailer-mounted spray tanks are even bigger. Folding booms on such sprayers can easily be 60 feet wide.

Nozzles or tips are mounted every few feet on sprayer booms. “Flat fan-spray” tips produce an overlapping tapered-edge spray pattern that provides uniform coverage. They work with both pre- and postemergent herbicides. “Flood-type” nozzles are normally reserved for liquid fertilizers. “Full” and “hollow-cone” nozzles deliver circular spray patterns and are most often used with insecticides or fungicides. Sprayer tips come in brass, plastic, ceramic, stainless steel and hardened stainless steel.

All sprayers must deliver just the right amount of “active ingredient.” Too little herbicide means poor weed control and repeat spraying. Too much may be hazardous to the applicator, or “phytotoxic” (injurious) to crop plants and leave excessive residues. That’s why weed scientists remind herbicide applicators to “calibrate” their sprayers by periodically measuring the amount of herbicide they deliver.

And anyone who has ever used a power-sprayer to paint will warn about the ever-present danger of “spray drift.” Even a slight breeze can blow herbicide mist on prize rose bushes and valuable vegetation that you don’t want to zap.

“Resistance” is another term increasingly linked with herbicides. “There are about 250 species of herbicide-resistant weeds in the world,” according to Purdue University. “The highest number is in areas where production row-crop agriculture is most intensive and relies almost exclusively on herbicides for weed control. That would be North America, Australia and Europe.” Nature developed herbicide-resistant “super weeds” around 1960, more than 30 years before genetic engineering gave us a few herbicide-resistant crop plants.

Here are 10 other things you can and should do to help control weeds on your place:

1. Stop Seeds Now – Never let any weed go to seed. “Weed seed populations in the soil should be kept to a minimum by preventing weeds from producing seed in and around vegetable fields. Destroy all weeds immediately after a crop is harvested,” cautions the Commercial Vegetable Production Recommendations from Penn State.

That’s why, no matter how many pressing chores there are to take care of around your property, you should always make time to at least mow your worst weed patches before they set seed and make the problem even worse. “But the days aren’t long enough,” you say. Nonsense! Why do you think tractors have headlights?

2. Bug ’Em Back – Release or encourage beneficial insects or diseases that attack various weeds. For instance, hairy weevils feast on seeds growing in the buds of yellow star thistle, reducing seed production. Three borers, including the raspberry cane borer, attack multiflora rose, according to Penn State. Instead of burning old raspberry canes, I pile them around the wild rose bushes in our fencerows. Rose rosette disease - indicated by the presence of witches’ broom and stunted, red shoots - kills multiflora rose, according to a report from Iowa State University.

3. Bury Weeds Alive! – After cutting weeds off low with a lawn mower or weed whacker, pour on the mulch, the thicker the better. You can also cover problem spots with layers of newspaper or landscape fabric before piling on the mulch. On fairly level ground with little risk of erosion, many farmers rely on deep plowing to bury troublesome weed seeds a foot or more below the surface.

4. Chop, Chop – For wild grape vines, poison ivy and greenbriar, I patrol our wooded fencerows and woodlot at least once a year. I cut through the vines near the ground with a Sandvik (Swedish brush ax), machete, bow saw or long-handled pruning loppers, and “extreme prejudice,” as Tom Clancy would say.

5. What’s For Dinner? – Weeds. Dust off the old Foxfire and Euell Gibbons books, such as Stalking the Wild Asparagus or Stalking the Healthful Herbs. Dandelions, chicory and other plants we now consider weeds were actually brought to this country by immigrants with a rich, nutritious history of foraging and “wild” eating.

6. FIRE Your Weeds – Flame weeding is nothing new. (See “Carrying the Torch” in the January/February issue of Grit.) Propane, which was first discovered in 1910, was commonly used to kill weeds in row crops throughout the United States by the late 1930s.

“Flaming was a very popular practice on corn, cotton and other row crops prior to the introduction of herbicides and pesticides,” according to Flame Engineering Inc., of LaCrosse, Kansas. “In fact, so much research was performed in the first half of the 20th century that flaming was fast becoming the primary method of weed control in cotton.” By the mid-1960s, however, cheap chemical herbicides and high propane prices nearly snuffed out flaming on most farms.

But the times keep a-changing. “Flaming is making a very successful comeback across the country and abroad,” say Flame Engineering experts. The reasons include increasing weed resistance to chemicals, environmental concerns and the growing popularity of organic foods. Flame Engineering’s 52-page catalog offers everything from hand-held torches fueled by a propane tank on a dolly or backpack to tractor-drawn flamers. Neither weeds nor insect pests can withstand temperatures of up to 2,000°F. Flame cultivation is being used successfully on up to 40 different crops, including corn, cotton, soybeans, potatoes, strawberries and even tomatoes.

Flaming kills weeds by boiling the water in plant cells. “The trick is to apply heat when weeds are small,” says Dr. Nabil Rifai of the Nova Scotia Agricultural College, in Truro, Nova Scotia, Canada.

7. Good Grazing – “Weeds are forages, too,” says Roger Becker, a professor of agronomy and plant genetics at the University of Minnesota-St. Paul. Pigweed, dandelion, white cockle, lambsquarters and ragweed are similar in composition and digestibility to alfalfa, the acknowledged queen of forages. Distant seconds include giant and yellow foxtail, shepherds purse and smartweed.

“Woolly weed whackers” such as sheep and goats are especially good for controlling unwanted vegetation through grazing. Sheep mostly graze flowering plants (forbs), while goats prefer shrubs. Sheep thrive on kudzu in the Southeast and are even used to control poisonous plants such as larkspur in cattle pastures, since sheep can tolerate three to four times more larkspur than cattle. Pigs root up even the most persistent weeds.

Just avoid over-grazing. That only encourages many weeds.

Weeder geese are favored by some organic growers. Chickens, which never seem to stop scratching, both cultivate and fertilize garden beds while eating weed seeds and bugs. Just be aware that your carefully planted seeds might be at risk as well, so let the chickens and geese loose after harvest.

8. Ho, Ho, HOE! – “Santa Claus Weed Control,” we call it.

“The earlier the hoe is used, the less work there will be later on,” advised Ehrenfried Pfeiffer, a pioneer of biodynamic farming and gardening, in his 1940s booklet, Weeds and What They Tell. “In the garden, the interspaces of the rows and between the plants should be kept clean from the very beginning. Once the weeds show up, it is often too late. Once the weeds form a green cover, it is impossible to get rid of them at reasonable expense.”

9. Mow, Mow, Mow Your Weeds – “Go thou, like an executioner. Cut off the heads of too-fast-growing sprays that look too lofty in our commonwealth,” Shakespeare advised in King Richard II.

We’re constantly whacking weeds around our place. For little touch-up jobs there is always the sickle or the scythe – the lightweight European scythe, not the heavy and awkward American scythe that makes your arms ache and palms blister after only a few strokes.

Larger jobs, like trimming under the split rail fence down front and around the trees, utility poles and farm sign by the road, fall naturally to our string trimmer. Our mowers range from a 22-inch walk-behind lawnmower and an 18-hp Cub Cadet lawn tractor with a 48-inch mower deck to a sicklebar mower on the old Farmall Cub and a 6-foot rotary mower on our John Deere 1050.

10. SELL Your Weeds – My wife, Melanie, does this all the time. At our weekly farmers’ market, she regularly laces some of her fresh-cut flower bouquets with foxtail, pokeweed, Queen Anne’s Lace, volunteer grains (oats, wheat, millet and more) and a variety of grasses that grow wild.

Sometimes, we just sell a bag of weed all by itself. Purslane (Portulaca) is a succulent green that has six times more vitamin E than spinach, plenty of iron and vitamins C and A, plus lots of lipid-lowering omega-3 fatty acids. It fetches $8 a pound and some farmers’ market regulars ask for it by name.

Now, if only we could find a market like that for thistles and galinsoga, maybe we could retire while we’re still young enough to enjoy this country life.   /G

George DeVault farms in southeastern Pennsylvania where he raises organic vegetables, blueberries – and bumper crops of poison ivy, Canadian thistle, galinsoga and purslane.  

hans quistorff
2/23/2013 7:13:01 AM

Qberry Farm sells Lamb's Quarters as well as the berries. I also use weeds t fight weeds. 12. Selectively allow weeds that are harvestable or complement your crop to grow and shade out the more objectionable weeds. For example around the base of my raspberry plants an unnamed weed comes up early each spring and starts blooming before the berries. this gets the pollinators working the patch and they switch to the berries when blooming plus this weed is very sensitive to heat and dies back leaving a fine mulch for the summer. There is an escaped annual called giant woodland orchid that grows between the Loganberries. These get 6 to 8 feet tall and shade the berries from scalding by the evening sun and have large snap dragon like flowers that again keep the bumble bees working the patch. The stems are shallow rooted and filed with water so as I clear picking space I can lay the along the the row and tramp them down to ad moisture and mulch to the row.