By: Mary H. Dyer, Credentialed Garden Writer
Burdock weeds are troublesome plants that grow in pastures, along ditches and roadsides and in many other disturbed areas across the United States. The weed is recognized by its large, oval or triangular “elephant-ear” leaves. The upper surface of the dark green leaves may be smooth or hairy and the lower leaf surface is typically wooly and pale green. The plant bolts in the second year and can reach heights of 3 to 10 feet. The small flowers, which are numerous, may be lavender, white, purple or pink.
Why are burdock weeds so troublesome, and why is burdock management so critical? Read on to find out how to get rid of this weed.
It’s extremely difficult to eradicate burdock. Seeds spread quickly when the seed heads dry and break, scattering thousands of seeds far and wide. The weeds also spread when the prickly burs catch a ride on passing people or animals.
Some people may experience unpleasant allergic reactions when the bristles contact the skin. The burs can cause real problems for livestock, resulting in eye infections, skin problems and mouth sores.
The plant can also host root rot, powdery mildew and other diseases that can spread to agricultural plants.
Digging, hand pulling or plowing can be effective ways of controlling common burdock when the weeds are small. These techniques don’t work well on larger plants because it’s difficult to remove the entire taproot. You can mow taller plants, but mowing must be done before the plant has bloomed or you will simply spread the seeds.
A number of herbicides are useful for controlling common burdock, including dicamba, 2,4-D, picloram, glyphosate and others. Unfortunately, burdock often grows in difficult, hard-to-access areas. Manual removal is often the only recourse as well as the most environmentally friendly.
Note: Chemical control should only be used as a last resort, as organic approaches are safer and much more environmentally friendly.
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Burdock, also known as gobo or Arctium lappa, is a edible plant native to Asia, although it now grows wild over much of North America and Europe and is considered a weed by many gardeners. Cooked burdock root is crunchy and has a mild flavor similar to potatoes or artichokes, and it can be used in soups and stir fries. Burdock root tea has traditionally been used as a detoxifier to treat acne, infections and liver problems.
Learn to positively identify burdock if you are harvesting it in the wild and are not growing it in a garden setting. Burdock grows up to 7 feet tall and has large, arrow-shaped leaves on thick stalks. The root is fat and deep. Mature plants produce spiky purple flowers similar to thistles and seed burrs that stick to clothing or fur. Always consult multiple sources to verify an identification before eating any wild plant. Most field guides to wild edibles should provide you with more information and illustrations for identifying wild burdock root.
Locate young burdock plants to dig. Burdock is a biennial, and the root become woody and unappetizing after the first year. Choose first-year burdock plants with only a rosette of leaves near the ground. Avoid plants with flowers or a flower stalk. First- year burdock root may be harvested in the summer or fall.
Dig a hole next to the burdock you wish to harvest. Begin digging a few inches away from the burdock stalk and dig down at least 1 foot. Burdock roots may be 2 or more feet long. Loosen the soil next to the root with your fingers or a hand trowel.
Press the shovel into the soil next to the burdock root on the opposite side of the hole you dug. Lean into the shovel to push the burdock root out of the hole.
Trim off leaves and feeder roots and rinse well. Do not peel. Store fresh burdock root in the refrigerator for a week or more to use as a food, or slice it thinly and dry it in a dehydrator or low oven to use medicinally.
If you wish to grow burdock in your garden, add a chunky mulch such as wood chips to the soil before planting. This will keep the soil loose and will aide in harvesting.
This homemade herbicide is by far the simplest to prepare, and unless you happen to spill boiling water on yourself, is also the least harmful to both people and the environment. Simply bring a big pot of dihydrogen monoxide (that's a fancy way of saying water) to boil on your stove, and then pour it over the leaves and stems of the weeds you wish to get rid of. Using boiling water is an effective method for killing weeds in places such as sidewalk or driveway cracks, or over a larger area that you'd like to replant after the weeds are gone, as it doesn't leave any residue or have any harmful long-term effects. As with all of these homemade herbicides, it's still important to only apply it to the plants you wish to get rid of, as they can easily also kill your flowers or vegetable plants.
In concentrations this strong, vinegar becomes hazardous and can cause environmental damage. Vinegar is a contact or "burndown" herbicide, killing what it touches within hours or days. The worst part is that it may looks like it’s working, but weeds will then resprout from the roots, particularly perennial species.
That partial success worries Jeff Gillman, author of The Truth About Organic Gardening, because it often incites a gardener to continue using vinegar, even if it's not the best for his or her garden. The gardener — seeing results but not entirely satisfied — often trades up to higher concentrations, replacing household vinegar (5% acetic acid) with a horticultural product (typically 20%).
Despite the signal word danger on most such labels, gardeners may instead just see vinegar and be careless. Sobering details: In concentrations over 11%, acetic acid can burn skin and cause eye damage, and concentrations of 20% and above are corrosive to tin, aluminum, iron, and concrete and can even cause blindness. Such herbicides should be applied while wearing goggles and protective clothing.
And then, Gillman says, there is potential environmental damage — such as to the toad or salamander shading itself beneath those weeds. "If you’re talking about just-sprouted seedlings, and you go after them right away with household vinegar , fine," says Gillman. Otherwise, it’s better to reach for a hand cultivator than a spray bottle.
Yellow Nutsedge (Cyperus esculentus)
Lawns and landscape plantings, common in moist areas but can survive in drier conditions
Hand removal difficult as stems break off from underground tubers which can then regrow and produce new plants persistent removal may eliminate plants.
Lawns: 8, 9, 10
Tubers are swollen portions of underground stems which aid in food storage for the plant.
Aliases: starweed, satin flower, tongue grass, passerina, clucken wort, skirt button
Rather than fighting it, several gardeners used chickweed as an edible green (one gardener tosses its leaves with honey and lemon juice to make a tasty salad) and take advantage of its medicinal properties (some make it into a salve to soothe skin irritation).
Chickweed is a low-growing, cold-tolerant annual that takes off in early winter. If you notice it then, turn it over with a fork and leave it in the garden. If you don’t get to it until early spring, switch to careful-hand-pulling-and-raking mode.
“Chickweed is the worst for me. It grows so quickly! If you pull it at the wrong time, the seeds pop out everywhere — argh! I hand pull early, then use fabric mulch to cover the spot” (Maryland gardener, 11 to 20 years of experience).
Several gardeners commented on how quickly this winter annual goes to seed. Seeds can germinate after being in the soil for up to 10 years, so if you have a major chickweed problem, stay on top of it before your plants set seed, and don’t compost chickweed plants no matter what stage of growth they’re in (chickweed seeds can continue to mature even after you pull the plant).
One respondent reported that this is the worst weed around perennial crops such as strawberries. It requires intensive hand weeding, but its roots are shallower and thus easier to handle than others that made our worst weeds list. Plus, it’s called chickweed for a reason: Many love feeding this weed to their poultry. “Just pull up the clumps and toss them to your ducks — they love it!” (Virginia gardener, more than 20 years of experience).