There’s really no such thing as a weed in nature. As Dwight D. Ligenfelter of the Department of Agronomy at Penn State University points out, weeds are simply plants “whose undesirable qualities outweigh their good points” in the eyes of human beings. Indeed, it is our human activities — farming, gardening, creating golf courses and parks — that create “weed problems.”
We tend to think of weeds as pests, plants who grow where they are not wanted and where we did not intentionally sow them. As weeds produce an abundant amount of seeds (which can survive while dormant for long periods of time), they are, says Ligenfelter, “naturally strong competitors” for the “water, light, soil nutrients and space” that are needed by the plants that humans seek to grow.
Weeds certainly have their drawbacks: they can be hosts for crop diseases, provide shelter for insects and produce substances toxic to plants, animals and humans (such as poison ivy). Not surprisingly, humans spend billions of dollars annually to control and eradicate weeds.
As Ligenfelter notes, however, weeds (which of course aren’t trying to push out human-planted crops) have numerous benefits, from stabilizing the soil to providing habitats and food for wildlife (milkweed for monarch butterflies) and for humans. These are some good weeds that can be welcomed in a yard rather than seen as the arch enemy:
Helen Atthowe of Vegan Permaculture observed that pennycress, a common roadside plant, did not compete with her crops and indeed attracted beneficial insects. She started to allow pennycress to spread with a view to it preventing other weeds more likely to compete with her crops from doing so. Rather than eradicating weeds, “editing” them can be beneficial.
Pennycress has other potential uses, as well. Researchers are investigating whether field pennycress might be a source of biofuel as its seeds contain an oil that has uses in producing biodiesel.
2) Lamb’s Quarters
Lamb’s quarters are just one type of weed (another is goldenrod) that protect your plants by luring away insects that can cause damage. Lamb’s quarters can also be eaten (though be careful, lest they’ve been planted in contaminated soil) and can provide up to twice as much or more of the nutrition of spinach or Swiss chard.
One urban forager notes they’re not so tasty raw. But saute them with a little olive oil and you’ll wonder how we can call them a weed rather than a nice addition to a spring meal.
While many seek to uproot it from lawns, clover actually used to be included in grass seed mixes as it helps to fertilize the soil. A legume, clover fixes nitrogen and adds it to the soil. Clover also attracts earthworms and, as rabbits like it, can lure them from eating your grass and any other crops. Even more, clover helps to shelter more moisture than it consumes and acts as a sort of “green mulch” or “green manure” for plants around it.
This weed may irk those wanting their lawn to look like a carpet, but it has numerous uses. The dandelion has a strong tap root that goes down far under the ground, breaking up hard soil and bringing up nutrients that plants with shorter roots can’t themselves access. Dandelions also exude minerals and nitrogen via their roots. Plus, they attract honeybees and repel army worms.
Dandelion leaves are edible, the young ones in salad and the older ones steamed. After being dried, chopped and roasted, the roots can be used to make a coffee substitute that is said to have detoxification effects.
Mugwort (also known as “felon’s weed”) grows in lawns, waste places, golf fairways, shores, roadsides and along railroad tracks. As it is resistant to mowing and has ”strong and persistent rhizomes,” it is not easily eliminated.
Peter Del Tredici, a senior research scientist at Harvard University’s Arnold Arboretum, calls mugwort the “quintessential urban weed.” It is not welcome by landscapers but has a number of properties, including absorbing heavy metals from the ground, helping to stop erosion on slopes and replenishing soil that has been stripped of nutrients.
As Ralph Waldo Emerson said, a weed is a plant whose virtues have not been discovered. Indeed, we might even say, in the words of Del Tredici, that “weed” is a “politically incorrect term” and an unfair “value judgment” on plants that have more than a little to offer us.
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