How to Identify Puncture Vine (a.k.a. the Goathead Monster)

This post originally appeared on Idaho Botanical Garden’s blog. With the first annual Boise Goathead Fest fast approaching, the purpose of this post is to help people in the Treasure Valley identify goatheads so that they can collect them for drink tokens to use at the event. I’m reposting it here in hopes that people around the globe who are tormented by goatheads might benefit from it. All photos in this post were taken by Anna Lindquist.

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If you have spent much time on a bicycle in Boise, chances are you have been the victim of a goathead-induced flat tire. You probably even got a good look at the spiky nutlet as you went to remove it from your tire. But where did the culprit come from? No doubt, it came from a plant. But which one?

This is particularly useful to know right now because the first annual Boise Goathead Fest is coming up, and if you manage to fill a garbage bag full of these noxious weeds before the end of July, you will earn yourself a drink token. Fortunately, this plant is fairly easy to identify; however, there are a few look-a-likes, so it is important to familiarize yourself with the plant in question so you can be sure you are pulling the right one.

puncture vine (Tribulus terrestris)

Puncture vine, also known as goathead or Tribulus terrestris, is a warm season annual that is native to the Mediterranean region of southern Europe. It was introduced to North America unintentionally by early European settlers when the plant’s blasted burs snuck their way across the ocean in sheep wool. Since then, puncture vine has spread across the continent prolifically thanks to the hitchhiking prowess of its seeds.

Behold, the infamous Goathead Monster.

Puncture vine has a prostrate habit, meaning that its branches lie flat on the ground, spreading outward from a central location. It grows upward only when it is being shaded or crowded out. Its leaves are divided into several tiny leaflets, and its flowers are small and bright yellow with five petals. It is an otherwise pretty plant were it not for the threatening, jagged fruits that follow the flowers. As these fruits dry, they dislodge from the plant, split into five pieces, and lay in wait to puncture your tire, work their way into the bottom of your shoe or the foot of an animal, or latch onto some errant fur.

puncture vine (Tribulus terrestris)

Depending on the conditions, puncture vine either remains fairly small or spreads as much as six feet wide. Fruits start forming shortly after flowering, and seeds ripen soon after that, so if the plant isn’t removed quickly – nutlets and all – future populations are guaranteed. Luckily the plants are fairly easy to remove. Unless the ground is particularly compact, they pull up easily, and if they break off at the root, they generally don’t sprout back.

Virtually any plant that has a prostrate growth habit and is actively growing in the summer could, at first glance, be mistaken for puncture vine. Closer inspection will help confirm the plant’s true identity. Two plants that might confuse you are purslane and spotted spurge. Both of these species can be found growing in full sun in disturbed or neglected sites in close company with puncture vine.

Purslane has tiny, yellow, five-petaled flowers similar to puncture vine; however, its leaves are glossy and succulent-like and its stems and leaves often have a red to purple hue to them. Purslane seeds are miniscule, and while the plant can be a nuisance in a garden bed, it poses no threat to bicycles or wildlife.

purslane (Portulaca oleracea)

Spotted spurge, also known as prostrate spurge, can be quickly distinguished by the milky sap that oozes from its broken stems. Its leaves are generally reddish purple on the undersides with a purple spot on top. Its flowers are minute and its seeds even smaller. Because its sap contains latex and other chemicals, it can irritate the skin and poison creatures that dare eat it.

spotted spurge (Euphorbia maculata)

Both of these plants are introduced, weedy species, so even if they won’t count towards your drink token, it still doesn’t hurt to pull them. Puncture vine, however, is included on Idaho’s noxious weed list, which means it is particularly problematic. So take this opportunity to pull as many as you can, and hopefully we can put a sizeable dent in the population of a plant that has tormented Boise bicyclists for far too long.

See Also: Plant vs. Bike

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The Creeping Charlies and Common Name Confusion

This is a guest post by John Tuttle.

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Most of us know creeping charlie as the all-too-often irritating weed which takes over our grassy lawns. This evergreen plant’s life cycle is year round. The garden-invading variety which sprouts little bluish-purple flowers has been given the title Glechoma hederacea (or sometimes Nepeta glechoma) via binomial nomenclature and is a member of the mint family, Lamiaceae. Additional common names for this creeping charlie include ground ivy, catsfoot, and field balm.

Travelers from Europe took the plant with them, distributing it throughout other parts of the globe, and it is now deemed an aggressive, invasive weed in various areas in North America. It has crenate leaves, and its size varies depending on its living conditions. It has two methods of reproduction. The first is made possible by offshoots called stolons (or runners), stems with the special function of generating roots and transforming into more plants. Thus, you will often find not an individual creeping charlie plant, but a whole patch, all of them connected via the runners. The other self-distribution method is simple: seeds.

creeping charlie (Glechoma hederacea) via John Tuttle

The creeper is edible, and if you were in a spot where you didn’t know when your next meal would be, this type of creeping charlie would probably be a welcome source of energy. Wild food educator, Karen Stephenson, suggests its use in simple dishes such as soups and omelets, but that’s probably for those who are cooking at home and not trying to fend for their lives in some forest. Starving in the woods is a bit of an extreme, but it has happened. Glechoma hederacea has also been used for making tea. It contains minerals like copper and iron, as well as a significant amount of vitamin C.

The weed also has a number of possible health benefits such as being a diuretic, anti-inflammatory, and antiviral. However, other researchers have cautioned people to be leery of consuming it as it has been known to be fatal to equines and bovines. It contains chemicals that can discomfit the gastrointestinal tract. It is further suggested that during pregnancy women should not intake any amount of any type of creeping charlie.

Up to this point you may have found the terms I’ve used, such as “this type of creeping charlie,” to be a little odd. In fact, the term creeping charlie does not refer to only a single species of creeper. It’s actually used for several.

Another plant hailed as “creeping charlie” is Pilea nummulariifolia of the family Urticaceae, a grouping otherwise known as the nettles. Pilea is the name of the genus of creeping plants; the artillery plant is also classified under this genus. Pilea nummularifolia is also known as Swedish ivy and is often grown as a houseplant. It is native to the West Indies and parts of South America. This viney plant flourishes when supplied with an ample amount of water.

creeping charlie (Pilea nummularifolia) via eol.org

Yet another plant commonly referred to as creeping charlie is Micromeria brownei, synonymously referred to as Clinopodium brownei. It is also used in some teas, but as mentioned above, pregnant women in particular should steer away from consuming it. Apart from the term creeping charlie, a few more common names for this plant include Browne’s savory and mint charlie. Like Glechoma hederacea, Browne’s savory is considered a mint. It produces flowers that are white with hints of purple on the petals and in the throat. This species is quite common in the state of Florida and in parts of Central America; although plants in this genus grow around the world.

Like Pilea nummularifolia, this species loves a good source of water. Its thirst for moisture is so strong, that it can actually adapt itself to an aquatic lifestyle, that is, one which occurs in water and not in dry soil. Many aquarists, people who enjoy keeping aquatic life, love this plant. It can also be trimmed with practically no damage to the plant. It is extremely durable and quite capable of adapting to different circumstances. For instance, Micromeria brownei can be situated midground inside a fish tank. The creeping charlie is perfectly at home totally submerged under water. If a plant floats to the surface then it should typically produce flowers. This adds a new dimension to some of the generic aquatic flora which is often used in many tank displays.

creeping charlie (Micromeria brownei synClinopodium brownei) via wikimedia commons

There you have it. Three different types of plants that have different uses and dangers, and they are all called creeping charlie. Be advised when you’re talking about true creeping charlie – Glechoma hederacea: the invasive weed with the purple flower – that you remember to specify, because “creeping charlie” could mean one plant to you and some plant from an entirely different family to another.

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John Tuttle is a Catholic guy with a passion for the media and creativity. Everything about science and health interests him. He’s a writer for publications such as ZME Science and Towards Data Science. John has started his own blog as well called Of Intellect and Interest. He’s also a published ebook author and the 1st place winner of the youth category of the 2017 Skeena Wild Film Fest. You can follow him on Facebook here, and he can be reached anytime at jptuttleb9@gmail.com.

Lettuce Gone Wild, part two

The lettuce we eat is a close relative to the lettuce we weed out of our gardens. Last week we discussed the potential that wild relatives may have for improving cultivated lettuce. But if wild lettuce can be crossed with cultivated lettuce to create new cultivars, can cultivated lettuce cross with wild lettuce to make it more weedy?

Because so many of our crops are closely related to some of the weeds found along with them or the plants growing in nearby natural areas, the creation of crop-wild hybrids has long been a concern. This concern is heightened in the age of transgenic crops (also known as GMOs), for fear that hybrids between weeds and such crops could create super weeds – fast spreading or highly adapted weeds resistant to traditional control methods such as certain herbicides. To reduce this risk, extensive research is necessary before such crops are released for commercial use.

flowers of prickly lettuce (Lactuca serriola)

There are no commercially available, genetically modified varieties of cultivated lettuce, so this is not a concern when it comes to crop-wild hybrids; however, due to how prevalent weedy species like prickly lettuce (Lactuca serriola) are, hybridization with cultivated lettuce is still a concern. So, it is important to understand what the consequences might be when hybridization occurs.

In a paper published in Journal of Applied Ecology in 2005, Hooftman et al. examined a group of second-generation hybrids (L. sativa x L. serriola), and found that the hybrids behaved and appeared very similarly to non-hybrid prickly lettuce. They also found that the seeds produced by the hybrids had a significantly higher germination rate than non-hybrid plants. This is an example of hybrid vigor. Thus, “if hybridization does occur, this could lead to better performing and thus potentially more invasive (hybrid) genotypes.” However, the authors cautioned that “better performing genotypes do not automatically result in higher invasiveness,” and that much depends on the conditions they are found in, the level of human disturbance, etc.

Another thing to consider is that hybrids are not stable. In an article published in Nature Reviews Genetics in 2003, Stewart et al. adress the “misunderstanding that can arise through the confusion of hybridization and … introgression.” It is wrong to assume that hybrids between crops and wild relatives will automatically lead to super weeds. For this to occur, repeated crosses with parental lines (also known as backcrossing) must occur, and “backcross generations to the wild relative must progress to the point at which the transgene [or other gene(s) in question] is incorporated into the genome of the wild relative.” That is what is meant by “introgression.” This may happen quickly or over many generations or it may never happen at all. Each case is different.

prickly leaf of prickly lettuce (Lactuca serriola)

In a paper published in Journal of Applied Ecology in 2007, Hooftman et al. observe the breakdown of crop-wild lettuce hybrids. They note that “fitness surplus through [hybrid vigor] will often be reduced over few generations,” which is what was seen in the hybrids they observed. One possible reason why this occurs is that lettuce is predominantly a self-crossing species; outcrossing is rare, occurring 1 – 5% of the time thanks to pollinating insects. But that doesn’t mean that a stable, aggressive genotype could never develop. Again, much depends on environmental conditions, as well as rates of outcrossing and other factors relating to population dynamics.

A significant expansion of prickly lettuce across parts of Europe led some to hypothesize that crop-wild hybrids were partly to blame. In a paper published in Molecular Ecology in 2012 Uwimana et al. ran population genetic analyses on extensive data sets to determine the role that hybridization had in the expansion. They concluded that, at a level of only 7% in wild habitats, crop-wild hybrids were not having a significant impact. They observed greater fitness in the hybrids, as has been observed in other studies (including the one above), but they acknowledged the instability of hybrids, especially in self-pollinating annuals like lettuce.

seed head of prickly lettuce (Lactuca serriola)

It is more likely that the expansion of prickly lettuce in Europe is due to “the expansion of favorable habitat as a result of climate warming and anthropogenic habitat disturbance and to seed dispersal because of transportation of goods.” Uwimana et al. did warn, however, that “the occurrence of 7% crop-wild hybrids among natural L. serriola populations is relatively high [for a predominantly self-pollinating species] and reveals a potential [for] transgene movement from crop to wild relatives [in] self-pollinating crops.”

Book Review: Good Weed Bad Weed

Distinguishing weeds from desirable plants is a skill that takes years of experience. If you’re not an avid gardener or a practiced naturalist, the distinction between the two groups may be blurry. There are weed identification guides aplenty, but even those aren’t always the most user-friendly and can often leave a person with more questions than answers. One of those questions may be, “Why is this plant considered a weed and not that one?” Through her book, Good Weed Bad Weed, Nancy Gift attempts to answer that question, offering much needed nuance to a regularly vilified group of plants.

In the introduction, Gift acknowledges that the term “good weed” sounds like an oxymoron. A weed, by definition, is an unwanted plant, an interloper and a troublemaker, without value or merit. What could be good about that? Gift, on the other hand, asserts that “it is a weakness of the English language that weeds are universally unwanted.” We need a word that describes plants that may have weedy characteristics but some redeeming qualities as well. For now, Gift uses “volunteer” – “a plant that comes up without being planted or encouraged” – suspending judgement until its performance can be fairly assessed.

Good Weed Bad Weed is a weed identification guide designed for beginners, for those wondering if their yard is “infested or blessed.” It is specifically concerned with weeds commonly found in lawns and garden beds, and “not meant to apply to farm fields or any other landscape.” It sets itself apart from other identification guides by organizing weeds into three categories: Bad Weeds, Not-So-Bad Weeds, and Good Weeds. Each plant profile includes a description, notes about benefits as well as problems, and some recommendations for control. Assigning good/bad designations to these plants is bound to cause some heated debate and outright disagreement, and Gift acknowledges that; however, we all have our “unique judgement” about the plants we encounter in our landscapes, so as “weed-lovers-in-training,” Gift hopes that we can “make a few new friends in the plant kingdom” and, perhaps, a few less enemies.

For the ten plants that make the Bad Weeds list, the reasoning is pretty clear. They are highly competitive and difficult to control [foxtail (Setaria spp.), garlic mustard (Alliaria petiolata), and Canada thistle (Cirsium arvense)], they are poisonous to humans despite being beneficial to wildlife [poison ivy (Toxicodendron radicans ) and poison hemlock (Conium maculatum)], they are known allergens and otherwise unattractive [common ragweed (Ambrosia artemisiifolia)], or, like Japanese knotweed (Fallopia japonica), they are on the list of top 100 worst invasive species.

The other two categories are where more personal judgement comes into play. The twelve plants considered Not-So-Bad Weeds are said to have “admirable qualities despite some negatives.” Prostrate knotweed (Polygonum aviculare) provides excellent erosion control. Orange hawkweed (Hieracium aurantiacum), bull thistle (Cirsium vulgare), and musk thistle (Carduus nutans) are quite beautiful and highly beneficial to pollinators and other wildlife. Nutsedge (Cyperus spp.) is edible and easy to keep in check if you stay on top of it. Bindweeds (Convolvulus arvensis and Calystegia sepium) avoid the Bad Weeds list because their flowers are so appealing. Aesthetics really matter to Gift, which is made clear with the entry for common fleabane (Erigeron philadelphicus), which could have made the Good Weeds list were it not for its disappointing and forgettable floral display.

field bindweed (Convolvulus arvensis)

As for the Goods Weeds list, more plant species find themselves in this category than the other two categories combined. That being said, those who have strong, negative opinions about weeds should probably avoid this section of the book, lest they experience an unsafe rise in blood pressure upon reading it. But be advised that making the Good Weeds list doesn’t mean that there are no negatives associated with having these plants in your yard; it’s just that the positive qualities tend to overshadow the negatives.

Positive qualities include edible, medicinal, low growing, slow growing, easy to control, beneficial to wildlife, not a bully, hardly noticeable, uncommon, and soil building. Certain weeds are desirable in lawns because they are soft to walk on, like ground ivy (Glechoma hederacea), yarrow (Achillea millefolium), and moss. Other weeds, like self-heal (Prunella vulgaris), stay green year-round and don’t leave ugly, brown patches when they die or go dormant. Still others, like bird’s-foot trefoil (Lotus corniculatus), black medic (Medicago lupulina), and clovers (Trifolium spp.) fix nitrogen, providing free fertilizer. Gift notes that, for those who keep chickens, weeds like common sorrel (Rumex acetosa) and cuckooflower (Cardamine pratensis) are great chicken feed.

Speaking of eating weeds, Gift concludes her book with four pages of recipes. The “Weedy Foxtail Tabouli” is particularly intriguing to me. Reading this book definitely requires an open mind, and some people simply won’t agree that any weed should ever be called “good.” Gift seems okay with that. She calls herself a “heretical weed scientist,” insisting that “a weed is in the eye of the beholder.” As “beholders,” I hope we can all be a little more like Nancy Gift.

A weedy lawn (photo credit: wikimedia commons)

More Book Reviews on Awkward Botany:

2017: Year in Review

Awkward Botany turns 5 years old this month! 

In the five years since I first introduced myself I have had the pleasure of sharing my writing and photos with thousands of people. Together we have formed a tiny community of nature lovers, botany nerds, and phytocurious folks. It has been fun seeing the audience grow and our interactions increase. The World Wide Web is a crowded and chaotic place, and you can never be sure what will come of the pieces of you that you throw at it. Luckily, my little project has not gone completely unnoticed. The crowd that enjoys it may be small, but it is composed of a solid group of people. Thank you for being one of those people.

If you were following along in 2017, you are well aware that weeds and invasive species have been regular themes. Both of these topics are still obsessions of mine, so while I don’t have plans to continue to saturate the blog with such posts, I will still be writing about them. I’m actually working on a larger project involving weeds, which you can read more about here.

Speaking of which, I have threatened a couple of times now to interrupt my weekly posting schedule in order to make time for other projects. So far that hasn’t really happened, but this year I am fairly certain that it will. It’s the only way that I am going to be able get around to working on things I have been meaning to work on for years. There are also some new things in the works. I think these things will interest you, and I am excited to share them with you as they develop. Once you see them for yourself, I’m sure you’ll forgive the reduced posting schedule.

One thing I have resolved to do this year is learn to draw. I love botanical illustrations, and I have always been envious of the artistic abilities of others. My drawing skills are seriously lacking, but a little practice might help improve that. While it is bound to be a source of embarrassment for me, I have decided to post my progress along the way. So even if you have less to read here, you will at least get to check out some of my dumb drawings. Like this one:

Drawing of a dandelion with help from Illustration School: Let’s Draw Plants and Small Creatures by Sachiko Umoto

One of my favorite things this year has been Awkward Botany’s new Facebook page. With Sierra’s help, we have finally joined that world. Sierra has been managing the page and is the author of most of the posts, and she is doing an incredible job. So if you haven’t visited, liked, and followed, please do. And of course, the invitation still stands for the twitter and tumblr pages, as well.

Lastly, as I have done in the past I am including links to posts from 2017 that were part of ongoing series. These and all other posts can be found in the Archives widget on the right side of the screen. During the summer I did a long series about weeds called Summer of Weeds, the conclusion of which has a list of all the posts that were part of that series. Thank you again for reading and following along. Happy botanizing and nature walking in 2018. I hope you all have a plant filled year.

Book Reviews:

Podcast Review:

Poisonous Plants: 

Drought Tolerant Plants:

Field Trips:

Guest Posts:

Highlights from the Alaska Invasive Species Workshop

This October 24-26th I was in Anchorage, Alaska for the 18th annual Alaska Invasive Species Workshop. The workshop is organized by the Committee for Noxious and Invasive Pests Management and University of Alaska Fairbanks Cooperative Extension. It is a chance for people involved in invasive species management in Alaska – or just interested in the topic – to learn about the latest science, policies, and management efforts within the state and beyond. I am not an Alaska resident – nor had I ever been there until this trip – but my sister lives there, and I was planning a trip to visit her and her family, so why not stop in to see what’s happening with invasive species while I’m at it?

What follows are a few highlights from each of the three days.

Day One

The theme of the workshop was “The Legacy of Biological Invasions.” Ecosystems are shaped by biotic and abiotic events that occurred in the past, both recent and distant. This is their legacy. Events that take place in the present can alter ecosystem legacies. Invasive species, as one speaker said in the introduction, can “break the legacy locks of an ecosystem,” changing population dynamics of native species and altering ecosystem functions for the foreseeable future. Alaska is one of the few places on earth that is relatively pristine, with comparably little human disturbance and few introduced species. Since they are at an early stage in the invasion curve for most things, Alaska is in a unique position to eradicate or contain many invasive species and prevent future introductions. Coming together to address invasive species issues and protect ecosystem legacies will be part of the human legacy in Alaska.

The keynote address was delivered by Jamie Reaser, Executive Director of the National Invasive Species Council and author of several books. She spoke about the Arctic and its vulnerability to invasive species due to increased human activity, climate change, and scant research. To address this and other issues in the Arctic, the Arctic Council put together the Arctic Biodiversity Assessment, and out of that came the Arctic Invasive Alien Species Strategy and Action Plan. Reaser shared some thoughts about how government agencies and conservation groups can come together to share information and how they can work with commercial industries to address the threat of invasive species. She stressed that Alaska can and should play a leadership role in these efforts.

Later, Reaser gave a presentation about the National Invasive Species Council, including its formation and some of the work that it is currently doing. She emphasized that invasive species are a “people issue” – in that the actions and decisions we make both create the problem and address the problem – and by working together “we can do this.”

Day Two

Most of the morning was spent discussing Elodea, Alaska’s first invasive, submerged, freshwater, aquatic plant. While it has likely been in the state for a while, it was only recognized as a problem within the last decade. It is a popular aquarium plant that has been carelessly dumped into lakes and streams. It grows quickly and tolerates very cold temperatures, photosynthesizing under ice and snow. It propagates vegetatively and is spread to new sites by attaching itself to boats and float planes. Its dense growth can crowd out native vegetation and threaten fish habitat, as well as make navigating by boat difficult and landing float planes dangerous. Detailed reports were given about how organizations across the state have been monitoring and managing Elodea populations, including updates on how treatments have worked so far and what is being planned for the future. A bioeconomic risk analysis conducted by Tobias Schwörer was a featured topic of discussion.

After lunch I took a short break from the conference to walk around downtown Anchorage, so I missed a series of talks about environmental DNA. I returned in time to hear an interesting talk about bird vetch (Vicia cracca). Introduced to Alaska as a forage crop, bird vetch has become a problematic weed on farms, orchards, and gardens as well as in natural areas. It is a perennial vine that grows quickly, produces copious seeds, and spreads rhizomatously. Researchers at University of Alaska Fairbanks found that compared to five native legume species, bird vetch produced twice the amount of biomass in the presence of both native and non-native soil microbes, suggesting that bird vetch is superior when it comes to nitrogen fixation. Further investigation found that, using only native nitrogen-fixing bacteria, bird vetch produced significantly more root nodules than a native legume species, indicating that it is highly effective at forming relationships with native soil microbes. Additional studies found that the ability of bird vetch to climb up other plants, thereby gaining access to more sunlight and smothering host plants, contributed to its success as an invasive plant.

 Seed pods of bird vetch (Vicia cracca) in Fairbanks, Alaska

Day Three

The final day of the workshop was a veritable cornucopia of topics, including risk assessments for invasive species, profiles of new invasive species, updates on invasive species control projects, discussions about early detection and rapid response (EDRR), and talks about citizen science and community involvement. My head was swimming with impressions and questions. Clearly there are no easy answers when it comes to invasive species, and like other complex, global issues (made more challenging as more players are involved), the increasingly deep well of issues and concerns to resolve is not likely to ever run dry.

Future posts will dig further into some of the discussions that were had on day three. For now, here are a few resources that I gathered throughout the workshop:

Interpretive sign at Alaska Botanical Garden in Anchorage, Alaska

Managing Spontaneous Urban Plants for Improved Aesthetics

As discussed last week, our wild, urban flora is a cosmopolitan mixture of plants that were either native to the area before it was developed, introduced from all corners of the world on purpose or by accident, or brought in by migrating wildlife. These are plants capable of establishing and sustaining themselves outside of human cultivation and management, and are found in abundance beyond the borders of our tidy gardens and manicured landscapes. They vegetate sectors of our city that have been abandoned, overlooked, or routinely neglected. Given enough time – and prolonged lack of intervention – such vegetation will proceed along the process of ecological succession in the same way that plant communities in natural areas do. And just like other plant communities within their respective ecosystems, these wild, urban plant communities provide a suite of ecological services vital to the health of our urban ecosystems.

Peter Del Tredici writes in Wild Urban Plants of the Northeast, “landscapes that include spontaneous vegetation fit the technical definition of sustainable in the sense that they are adapted to the site, require minimal maintenance, and are ecologically functional.” In an interview with Scenario Journal, Del Tredici goes on to define sustainability as “the value of the services provided by the ecosystem divided by the cost required to maintain that ecosystem.” Spontaneous urban landscapes offer “substantial ecological services at relatively low cost, or in some cases no cost,” and thus, by Del Tredici’s definition, they are “highly sustainable.”

There is one unfortunate downside – “weedy” landscapes like this are, by popular opinion, thoroughly unattractive and a sign of urban decay. This belief is held in spite of the fact that many of the plants found therein would be cherished or admired in other settings. Among deteriorating infrastructure, litter, and less attractive plants, some of our favorite plants are rendered guilty by association.

Despite their ecological benefits, abandoned areas vegetated with wild, urban plants are not favored by the public. So, to appease our aesthetic standards, sites like this can be enhanced through minimal intervention to be more attractive while retaining their ecological functions. In a paper published in a 2006 issue of Journal of Landscape Architecture, Norbert Kühn asserts that “to use spontaneous vegetation for ornamental purposes, a kind of enhancement or design work is necessary.” Species can be added and removed, and simple, infrequent maintenance measures can be implemented. Examples include extending the flowering season with spring flowering bulbs and mowing the area once or twice annually to maintain and improve the composition of the stand.

Wild bergamot (Monarda fistulosa) – one of the plants that Norbert Kühn included in his study as a candidate for improving the aesthetics of spontaneous, urban plant communities.

Favoring attractive weeds over less attractive ones and using minimal maintenance to improve aesthetics and function are the principles behind Del Tredici’s “cosmopolitan urban meadow.” In his book, he lists some criteria for plants that would be suitable for “this novel landscape form,” including: erosion control (long-lived; vegetatively spreading), stress tolerance (full sun; drought; compacted and polluted soil), aesthetic value (ornamental characteristics; not “weedy” looking), wildlife friendly (attractive to pollinators; edible seeds), and commercially available.

In an article in Harvard Design Magazine, Del Tredici and Michael Luegering describe the cosmopolitan urban meadow as “a stable assemblage of stress-tolerant, low-maintenance herbaceous perennial plants that are preadapted to harsh urban conditions and that will provide an attractive vegetation cover on vacant land.” Whether it is a “long-term landscape feature” or a placeholder until future development, it will have “the capacity to increase the aesthetic and ecological value of vacant land without the investment of large sums of money typically required for the installation and maintenance of traditional managed landscapes.”

Abandoned or undeveloped, urban lots like this one are ideal sites for “cosmopolitan urban meadows.”

In an urban context, some plant species are particularly noxious and may need to be removed from urban meadows, such as ragweed (Ambrosia spp.) for its allergens and poison ivy (Toxicodendron radicans) for its Urushiol-induced contact dermatitis. Species with a history of being invasive should also be avoided and contained, particularly in sites that are adjacent to or within a short distance from natural areas. Despite this and other minor concerns, spontaneous vegetation has great potential. In Kühn’s words it is “authentic” and a “reminder of the history of the site,” it is part of “the natural dynamic” with potential to bring us “closer to nature,” and finally, “it can be maintained for a long time [with] less care and low costs.”

Finding beauty in these urban, wild landscapes might even cause a shift in what we find appropriate for cultivated landscapes. In her book, Grow Curious, Gayla Trail reminds us that, despite all of our efforts, wildness persists even in our most earnest attempts to subdue it. Perhaps we should embrace it:

‘Wild’ and ‘cultivated’ are social constructs that we place in opposition to each other, when in reality there is a knotty labyrinth between them. We subjugate our cities and our gardens with chemicals and artifice because we are unable to see that wild and cultivated can be entwined, can be all at once tended, lyrical, surprising, domesticated, irrational, functional, and free.

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See Also: Arnold Arboretum’s Cosmopolitan Meadow at Weld Hill