The Importance of Urban Meadows
Why are urban meadows important?
Overall, we humans have not been very kind to the environment. We have cut down forests, paved over prairies, drained wetlands, destroyed habitat, sickened bees, polluted waterways, and even started to upset the climate. None of these is trivial, we depend upon the environment, a habitable climate, and natural resources for food, water, fresh air, building materials, energy, recreation, beauty, security, and more. Basically we have a pact with the Earth: respect her, or perish. Earth will be fine either way. So it is in our best interest to live in greater harmony with Earth. Urban meadows are a very small, but imminently do-able, item on that list.
Urban meadows are both symbolic and functional. Both are important. Let's start with functional.
Urban meadows are the natural progression of many efforts to plant native perennials, trends toward use of native grasses in landscapes, and increased interest in having a garden without increased interest in maintaining a garden. Urbanmeadow.org is all about how to appreciate urban meadows, how to design an urban meadow, how to grow an urban meadow, and living with an urban meadow. Urban meadows can grow on the tiniest plot of land in front of a townhouse, to massive swaths of land such as Lurie Garden in Chicago's Millennium Park, or The High Line in New York City.
You might think "How is this any different from just planting native perennials or flowering plants?". Basically this is just a progression of the same ideas. The progression is toward thinking of plants not as specimens, or even massings, but as self-sustaining communities.
Meadows, wetlands, and forests provide the highest benefits. Meadows have the most potential for broad adoption in urban areas.
|Aesthetics||Maintenance||Energy (gas, electric)||Stormwater retention||Stormwater detention||Fertilizer||Pesticide||Herbicide||Pollinator habitat||Bird habitat||Irrigation|
|Sheared Shrubs||simple, finicky|
|Ornamental Perennials||high, seasonal|
|Native Perennials||complex, seasonal|
|Native Grasses||complex, seasonally variable|
|Meadow||highly complex, seasonally variable|
|Wetland||complex, seasonally variable|
|Forest||complex, seasonally variable|
The table above [will] outline comparative differences between some different horticultural and ecological approaches. A few key takeaways include:
- The most broadly accepted "conventional" landscapes (mown grass and sheared shrubs) have a very simple aesthetic (low variation in color, texture, shape, seasonal variety).
- Conventional landscapes are very high maintenance (high energy, high chemical, high irrigation, and high labor demands).
- Conventional landscapes provide negligible ecological benefits (habitat, stormwater, habitat, cooling, etc.).
- As landscapes approach a more "natural" form (i.e. similar to found in the wild), the aesthetic becomes more complex.
- As landscapes approach a more "natural" form, maintenance needs drop, requirement of energy inputs drop, and ecological value rises.
- Meadows, wetlands, and forests provide the highest benefits. Meadows have the most potential for broad adoption in urban areas.
What do we mean by "self-sustaining communities"?
A self-sustaining plant community is a group of plants - usually multiple species - that thrives with little help from us humans. Self-sustenance is important! Let's take for instance turfgrass. Turfgrass relies on people for its very survival, as without the constant mowing, taller plants would take its place. Without chemicals, often non-turfgrass species such as dandelions take its place. On the other hand, you can probably picture and old field, or a vacant lot, or an abandoned home where nature is left to "do its own thing", i.e those plants are not relying on humans at all.
An urban meadow is a self-sustaining plant community that thrives with little help from us, but which isn't so hands-off as to be unruly. But the important part is that most or all needs of urban meadows are met by the sun, rain, air, and soil. And that is super important! Traditional landscaping and gardening can have a moderate to high carbon footprint, water requirements, and/or create nutrient pollution. Self-sustaining plant communities - on the other hand - are carbon sinks.
Urban meadows increase biodiversity. Biodiversity just means multiple different species, and is usually measured relative to a baseline (such as a natural meadow or forest). The baseline is often existing diversity, when discussing an "increase" or "decrease" in biodiversity.
For example, if a city has 10,000 elm trees, but only 20 Kentucky coffee trees, then planting more Kentucky coffee trees will increase biodiversity (because there were few, and now there are more). Similarly, if there are no daisies in an area, and you plant daisies, you have just increased biodiversity. On the other hand, in a city where the majority of plants present are maple trees, boxwood shrubs, coneflowers, and turfgrass, then planting any more of these plants does not increase biodiversity.
So why is biodiversity important? Urban meadows are communities, and communities support each other. When one species suffers, another might take its place until the population rebounds. There is even a phenomenon where "companion plants" help each other ward off pests. A diversity of plant species is especially important to support a diversity of microbial, insect, and bird life. Diversity is the foundation of a successful, resilient ecosystem.
Some conversations within the green roof industry might be good examples for discussing biodiversity. Sedum is the most common type of green roof plant, and Sedums are usually a very small percentage of any plant community outside of green roofs and some Alpine or semi-arid locations. Sedum green roofs are often criticized for "not providing biodiversity". But since most places do not already have much Sedum, planting Sedum usually increases biodiversity. Mixing other plants in with the Sedum might increase plant or insect biodiversity even more, depending upon what is already present.
So, then, how can we justify a blanket statement that urban meadows increase biodiversity? That might not always be accurate, particularly if a meadow is growing only species already found in abundance in an area. "Wild" landscapes are almost certainly a minority of landscapes in any urban area, and urban meadows will usually include a few species not found in the surrounding manicured plantings, at least not found in any quantities. Ornamental grasses, coneflowers, black-eyed Susans, and daisies have become common landscape plants, but chances are that their populations are relatively low in any given area, and that adding them to urban meadows will increase populations. And chances are even greater that urban meadows will support some species who find no other home in the city.
Plants cool the environment, primarily via evapotranspiration. Transpiration is a process where plants take up water from the soil and evaporate it via pores in their leaves. Evapotranspiration is the combination of transpiration + evaporation that occurs just when soil, pavement, leaves, and other wet surfaces dry in the sun. This process is basically an energy transfer: heat from the sun evaporates water, which enters the atmosphere as a vapor. Evapotranspiration is how urban meadows help so much in cooling.
Stormwater retention and cooling go hand-in-hand. Stormwater retention is water that is retained, or held, by the plant or the soil and which never runs off. Retained stormwater is the same water used for evapotranspiration, so stormwater retention and evapotranspiration are the same values, which is why retention and cooling are so closely interlinked.
Many meadow plants are ideally suited to provide high retention / evapotranspiration due to their leaf structure or root structure.
Another aspect of stormwater is detention, or delay. This is the slowing of runoff, i.e. runoff still occurs, but more slowly than it would otherwise. Let's say all the retention than can occur has occurred, i.e. the soil is wet, and plants have taken up as much water as they need. The rest will run off. Stems and twigs within an urban meadow can slow that water down, which is a benefit to prevent overloading the storm drain all at once. There are many ways to detain stormwater, and urban meadows might or might not help much, depending upon site-specific conditions.
Everything we do has some impact. Is that impact high or low? Beneficial or detrimental?
For example, a weedy area could be converted to a planting bed full of flowers that attract bees and butterflies. Sounds great, right?! But if the weeds were removed with herbicide, and if the newly planted flowers require much more water than natural rainfall, and if the flowers are fed a steady diet of fertilizer... then this landscape "looks" like it provides environmental benefits, while actually polluting and damaging on-site and offsite ecosystems.
Urban meadows have a beneficial environmental impact.
Much of the reason for this is visible: more greenery, more biomass, pollinator habitat, etc. Other reasons for these benefits are largely invisible: minimal or no pesticide, herbicide, fertilizer, or irrigation.
Erosion Control / Slope Stabilization
Urban meadows are great for slope stabilization! Why? Because many meadow plants, particularly tall grasses, have extensive fibrous root systems that hold together soil. Further, urban meadow plants grow together densely, such that little or no ground is visible; this density of roots, shoots, and stems slows down water, protects the surface of soil, and holds soil in place.
The greatest controversies I have encountered regarding urban meadows have to do with aesthetics. Some people just don't like how they look. Aesthetics is a tricky measure of importance. It's easy to say that aesthetics really don't matter to the environment. But people tend to have very strong feelings about aesthetics. Many people experience biophilia, a tendency to be drawn to nature, and react positively toward greenery in the city. Since people make decisions about the built environment, it is important to take aesthetics into account when designing urban meadows.
Urban meadows can be great educational tools! Better ecological education is crucial for human survival, and ecology is an area not traditionally emphasized by many schools. There are abundant opportunities for schools to design, plant, maintain, monitor, or just appreciate urban meadows as something of a microcosm of ecology.
Urban meadows not only provide tangible benefits, they are small enough that we can understand as a means to better understanding macro-ecology. It is critical that a majority of the population understands and cares about global environmental threats before there is support to mitigate those threats.
a personal note from Brad Garner
The symbolism of urban meadows is very important to me. But less so as an outward symbol ("Look at me! I'm so green my landscape is tall and messy!") but more as a reminder to self. Many of the things we do to lessen our ecological footprint are small things, and things that are hard to see. Using less water in the shower, eating organic, eating less meat, recycling, reducing overall consumption, driving less, composting instead of buying fertilizer, installing solar panels, and voting accordingly. Some of these are invisible. Many of these aren't great conversation starters. Some of these may be polarizing to some. Many of these don't feel tangible, and I need to feel and see something that embodies these ideals!
Not only are urban meadows functional, they are great visual reminders, and for me a great source of joy. The colors and textures remind me of fields far from the city. The upward arching of branches, the irregular contours, and the contrast of light and shadow and bright green and dark purple remind me of edges of a forest. Bees, birds, and butterflies visit and - with the trickle of a small fountain - create a constant source of activity. When the wind blows, grasses, stems, leaves, and flowers move just enough to remind me to enjoy the breeze. When I pull weeds - which is rare these days - I sense the benefits (less work!) from years of paying attention to the plants and cultivating plant communities that thrive and do not invite weeds. When I come home, I often hear crickets chirping when I approach, a reminder that beneath the foliage lies an ecosystem of microbial life that supports small insects which, in turn, support larger insects. Im sure birds eat a few of those.
Even though I have probably done more environmental good by covering my roof with solar panels, working from home, and reducing our meat consumption, I get more continued joy from my urban meadow, which provides benefits to the environment and to my psyche. Isn't that sustainability?