By Lauren Lewis
A weed is simply a plant growing where it is not wanted. But there’s nothing inherently ugly or unpleasant about garden weeds as a category; in fact many are quite lovely, and not so different from their relatives that we plant on purpose.
Weeds are only unwanted because their impressive growth characteristics allow them to spread quickly in places they haven’t been invited and outcompete more desired plants. They are plants that have evolved to be the earliest, fastest growers after a disturbance in the environment. A disturbance could be a fire, a flood, a fallen tree that leaves newly exposed soil, the planting of a garden. Weed seeds are fastest to germinate, and their seedlings grow quickly, collecting more resources than their non-weedy neighbors. Weedy plants typically flower faster than other plants, and many have seed characteristics that aid wide dispersal, such as parachute shapes (like dandelion puffs) or hooks for velcroing to fur and pants (burrs).
All of these characteristics mean that weeds can dominate a disturbed environment soon after the disturbance. In a typical garden the disturbance is constant, which means the weeds are also constant. But in a natural environment following a single disturbance event, the pioneering weeds slowly change the environment in ways that encourage growth by the next types of plants- shrubs, small trees, etc. The weedy growth builds organic matter in the soil, the roots change soil structure, the plants can change the soil’s pH and mineral composition.
Weeds provide these crucial services to recovering natural environments, and despite their bad rap they also provide various under appreciated services to humans. For example, weeds and their roots protect our urban, oft-disturbed soil from erosion during rain. In a garden setting mulch can provide some of that same service, but weeds are substantially more effective since they are tethered to the soil by their roots.
Grasses are a massive category of weedy plants that provide humans with another crucial service: grains as a food source. Grasses are highly adaptive and dominant in habitats everywhere except Antarctica, with fast growth and a low growth point that lets them survive trampling and grazing. The earliest agriculture was cultivation of grasses for grain, and today grasses account for the majority of agricultural crops (wheat, rice, corn!).
For these reasons and many more, some creative folks are trying to give weeds a boost in reputation, using a variety of interesting methods. Spontaneous Urban Plants is a crowd-sourced mapping and research project aimed at noticing, understanding and celebrating the various benefits of the weeds growing in New York City. Weeds catalogued by the SUP project are categorized by the particular benefits they perform, including urban heat mitigation, carbon sequestration, food, wildlife habitat and many more. The project aims to subvert the negative assumptions about weeds in a way that can positively influence urban design.
Mona Caron is a muralist and photographer who is using her art to raise weeds up a notch. She happens to be San Francisco-based, and you’ve likely noticed some of her iconic murals around the city (above). Caron views weeds as under appreciated in their beauty, so she paints murals of giant healthy weeds, allowing her subjects to demand the attention she thinks they deserve.
At the small scale of a single garden, one can carry out the same kind of garden rebellion by simply questioning the decision to remove a weed. Is it preventing another plant from growing? Using fresh eyes, how does it look to you? Some plants that previously would have been pulled automatically might hold a new form of appeal. And even if you can’t find their beauty, you can boost the health of your soil by cutting weeds off at the ground level instead of pulling. Cutting the weed off and leaving the roots intact helps maintain soil structure and avoids the soil disturbance that patient weed seeds are waiting for. By keeping all or part of our weeds around, we can create healthier and maybe even more interesting natural spaces.