Concluding the Summer of Weeds

“Most weeds suffer from a bad rap. Quite a few of the weeds in your garden are probably edible or even medicinal. Some invasive plants, including horsetail and nettle, are rich in minerals and can be harvested and used as fertilizer teas. Weeds with deep taproots, such as dandelions, cultivate the soil and pull minerals up to the surface. … Weeds are nature’s way to cover bare soil. After all, weeds prevent erosion by holding soil and minerals in place. Get to know the weeds in your area so you can put them to use for rather than against you.” — Gayla Trail, You Grow Girl

Great Piece of Turf by Albrecht Dürer (photo credit: wikimedia commons)

With summer drawing to a close, it is time to conclude the Summer of Weeds. That does not mean that my interest in weeds has waned, or that posts about weeds will cease. Quite the opposite, actually. I am just as fascinated, if not more so, with the topic of weeds as I was when this whole thing started. So, for better or worse, I will much have more to say on the subject.

In fact, I am writing a book. It is something I have been considering doing for a long time now. With so many of my thoughts focused on weeds lately, it is becoming easier to envision just what a book about weeds might look like. I want to tell the story of weeds from many different angles, highlighting both their positive and negative aspects. There is much we can learn from weeds, and not just how best to eliminate them. Regardless of how you feel about weeds, I hope that by learning their story we can all become better connected with the natural world, and perhaps more appreciative of things we casually dismiss as useless, less quick to jump to conclusions or render harsh judgments about things we don’t fully understand, and more inclined to investigate more deeply the stories about nature near and far.

Of course, I can’t do this all by myself. I will need your help. If you or someone you know works for or against weeds in any capacity, please put us in touch. I am interested in talking to weed scientists, invasive species biologists, agriculturists and horticulturists, edible weed enthusiasts, plant taxonomists, natural historians, urban ecologists, gardeners of all skill levels, and anyone else who has a strong opinion about or history of working with weeds. Please get in touch with me in one of several ways: contact page, Facebook, Twitter, Tumblr, or by commenting below.

Another way you can help is by answering the following poll. If there is more than one topic you feel particularly passionate about, feel free to answer the poll as many times as you would like; just wait 24 hours between each response. Thank you for your help! And I hope you have enjoyed the Summer of Weeds.

Quick Guide to the Summer of Weeds:

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Summer of Weeds: Wild Urban Plants of Boise

The Summer of Weeds is a result of the curiosity and fascination I feel towards weeds. It is also inspired by Peter Del Tredici’s book, Wild Urban Plants of the Northeast, which encouraged me to take a closer look at the weeds that grow in my urban hometown of Boise, Idaho. Del Tredici’s book serves mainly as a field guide for identifying common weeds found in urban areas in the northeast region of the United States. Many of these weeds are found in cities across North America, so the guide is still useful regardless of where you live. Additionally, the book’s 25 page introduction is an excellent overview of how weeds fit in to the ecology of urban areas and an incentive to not only stop and get to know our urban flora but to respect it for its tenacity and durability and its important ecological role.

Excerpts from Wild Urban Plants of the Northeast by Peter Del Tredici:

From the Foreword by Steward T. A. Pickett –

If it is to fulfill its potential, the urban wild flora must be better understood and better used. In other words, its functions, not just its categories – native, exotic, invasive, naturalized – must be appreciated by professionals and citizens alike. Understanding should come before judgement when urban wild plants are concerned.

Defining urban wild plants –

The [plants] that fill the vacant spaces between our roads, our homes, and our businesses; take over neglected landscapes; and line the shores of streams, rivers, lakes, and oceans. Some of the plants are native to the region and were present before humans drastically altered the land; some were brought intentionally or unintentionally by people; and some arrived on their own, dispersed by wind, water, or wild animals. They grow and reproduce in the city without being planted or cared for. They are everywhere and yet they are invisible to most people. Given that cities are human creations and that the original vegetation that once grew there has long since disappeared, one could argue that spontaneous plants have become the de facto native vegetation of the city.

Why weeds are problematic in agricultural and horticultural settings, as well as in natural areas, is fairly intuitive. But why are they seen as a problem in urban areas, outside of our parks, yards, and gardens? –

When it comes to spontaneous urban plants, people’s complaints are usually aesthetic (the plants are perceived as ugly signs of blight and neglect) or security related (they shield illicit human activity or provide habitat for vermin). Indeed, the context in which a plant is growing not only determines the label that we put on it but also the positive or negative value that we assign to it.

Regarding urban ecology – 

[Cities] have their own distinctive ecology, dominated by the needs of people and driven by socioeconomic rather than biological factors. People welcome other organisms into cities to the extent that they contribute to making the environment a more attractive, more livable, or more profitable place to be; and they vilify as weeds those organisms that flourish without their approval or assistance. Regardless of humans’ preferences, an enormous variety of nonhuman life has managed to crowd into cities to form a cosmopolitan collection of organisms that is every bit as diverse as the human population itself.

To illustrate the point that urban weeds are playing a role in the ecology of our cities, Del Tredici lists the ecological functions of each species featured in the field guide portion of the book. These functions include:

  • temperature reduction
  • food and/or habitat for wildlife
  • erosion control on slopes and disturbed ground
  • stream and river bank stabilization
  • nutrient absorption (nitrogen, phosphorous, etc.) in wetlands
  • soil building on degraded land
  • tolerance of pollution or contaminated soil
  • disturbance-adapted colonizer of bare ground

Carbon storage and oxygen production are functions of these plants as well, as they are of all plants; however, as Del Tredici points out, “because [spontaneous urban plants] grow on marginal sites and require no maintenance, [they] are probably providing a greater return in terms of carbon sequestration than many intentionally cultivated species.”

There is much more to say about this “brave new ecology” and the role that urban wild plants play in it. Future posts are in the works. For now, consider this sentiment from Del Tredici’s book: Urban wild plants “are well adapted to the world we have created and, as such, are neither good nor bad – they are us.”

What follows are a few photos of some of the urban wild plants I have encountered in Boise over the last few weeks. These, along with the plants featured in previous Summer of Weeds posts, are a mere fraction of the species that grow wild in my urban hometown. The diversity of weeds alone in urban areas is astounding and should be given more consideration, along with the broader diversity of organisms that exist within our cities.

Creeping wood sorrel (Oxalis corniculata) along the driveway in front of my apartment

Prickly lettuce (Lactuca serriola) in an abandoned lot on Bannock Street

Yet to be identified thistle along 23rd Street

Field horsetail (Equisetum arvense) in front of post office on 13th Street

Pale smartweed (Polygonum lapathifolium) in a ditch at Idaho Botanical Garden

Tree of heaven seedling (Ailanthus altissima) in the backyard of my apartment

Birdsfoot trefoil (Lotus corniculatus) in the lawn at Esther Simplot Park

Weeds taking over a recently abandoned business on 27th Street

Creeping bellflower (Campanula rapunculoides) in the alleyway behind my apartment

Showy milkweed seedlings (Asclepias speciosa) next to horizontal juniper in a median on Parkcenter Boulevard

Purple loosestrife (Lythrum salicaria) on the bank of the Boise River near the Broadway Avenue bridge

Himalayan blackberry (Rubus armeniacus) along the Boise River Greenbelt near MK Nature Center

Summer of Weeds: Flower of an Hour

Hibiscus trionum is a great example of an ornamental plant becoming a widespread weed. Its common name, flower of an hour, refers to its short-lived blooms. Other common names include Venice mallow, bladder hibiscus, bladderweed, modesty, and shoofly. Native to southern Europe and tropical to subtropical parts of Asia and Africa, it was introduced to America as an attractive addition to annual flower beds. It is now naturalized in many states across the country.

Hibiscus is a huge genus in the family Malvaceae, consisting of species found throughout warmer parts of the world. H. trionum is a warm season annual that grows to around two feet tall and has the habit of a sprawling, decumbent vine; an upright, many-branched mound; or something in-between. Its leaves are alternately arranged and three-lobed with coarsely toothed margins. The flowers are solitary and borne in the axils of leaves. They are creamy white to pale yellow with a purple-brown center, and are both cross- and self-pollinated.

flower of an hour (Hibiscus trionum)

Flowering occurs on sunny days throughout the summer. The ephemeral flowers promptly produce a balloon-shaped seed capsule that is hairy and papery with prominent purple veins. Once mature, the capsules split open at the top to reveal five compartments lined with brown to black, kidney- or heart-shaped seeds. Every part of this plant is attractive and interesting to look at, which is why it is no surprise that it is welcome in many flower beds.

Seed capsule of flower of an hour (Hibiscus trionum)

Sites that are in full sun with fertile soil and regular moisture are sought after by flower of an hour. Less fertile soils are still prone to invasion. As with many weeds, disturbance is key, so it is often found in agricultural fields, rangelands, along roadsides, and in vacant lots and construction sites. Its presence in natural areas is a result of escaping from garden beds, agricultural fields, etc.

When we choose to grow plants that have a history of escaping into natural areas, we should be aware of both our proximity to natural areas and the dispersal mechanisms of the plants. Exotic plants that reproduce reliably and prolifically by seed, such as flower of an hour, should be considered unsuitable for gardens that are adjacent to natural areas.

This is because many popular ornamental plants have become invasive in the wild. Plants that are perfectly welcome in our gardens manage to find suitable habitat in natural areas, potentially threatening the livelihood of native plants and/or altering ecological processes such as fire regimes. An example of this where I live is bachelor’s buttons (Centaurea cyanus), which has escaped from gardens and invaded the Boise Foothills. While the impact of this invasion is not well-studied, the speed at which this plant has spread is disconcerting. Even more disconcerting is the fact that seeds of this and other European and Asian species are commonly found in “wildflower” seed mixes distributed throughout North America.

While I am sympathetic towards weeds, I also see them as one of the best reminders of the impacts that humans can have on the planet. They are clear indicators that every step we take has consequences. We should be mindful of this, and we should continue to have the tough conversations that issues like weeds and their impacts encourage us to have. There are no easy answers, but the dialogue must go on. Because all of us – gardeners and non-gardeners/ecologists and non-ecologists alike – generally have an opinion about weeds, they seem like a pretty good place to start.

Additional Resources:

Quote of the Week:

From the book Invasive Plant Medicine by Timothy Lee Scott

The nature of a weed is opportunistic, and we, as humans, have created enormous holes of opportunity for these plants to fill. They have adapted to be at our side, waiting for those favorable times to cover the exposed soils that we continually create. With ever-changing genetics of form, function, and transmutation, weeds have evolved to withstand the punishments that humans unleash upon them.

Summer of Weeds: Stinking Lovegrass

There are so many weedy grasses that we would be remiss if we let the Summer of Weeds go by without discussing at least one of them. As obnoxious and ecologically harmful as some of these grasses can be, they are easy to ignore, simply because they are not as showy and eye-catching as other weeds. They can also be difficult to identify, particularly when they are not flowering. To the untrained and unappreciative eye, all grasses appear alike and most are fairly uninteresting.

But some of them have great common names, like Eragrostis cilianensis, commonly known as stinking lovegrass, candygrass, or stinkgrass. This plant earns the name “stink” on account of the unpleasant odor that is released through tiny glands in its foilage and flower head. Probably due to my poor sense of smell, my nose doesn’t pick it up very well, but from what I can tell it has a funky or, as Sierra put it, “musky” smell. I imagine if you were to come across a large patch of stinking lovegrass blowing in the breeze, the smell would be detectable.

stinking lovegrass (Eragrostis cilianensis)

Eragrostis cilianensis is a short (up to two feet tall) annual grass from Eurasia and Africa. It is naturalized across much of North America. It has hollow and jointed stems with flat or folded leaves. Where the leaf blade wraps around the stem (an area called the ligule) there is a tuft of fine hairs. The inflorescence is highly branched, and the branches are lined with several compact, flat florets. The appearance of the flower head is highly variable, from tight and compact to spread out and open.

Inflorescences of stinking lovegrass (Eragrostis cilianensis)

Stinking lovegrass likes sandy or gravelly, dry soils in open, regularly disturbed areas with full sun. It is very drought tolerant and thrives in hot temperatures, which is why it is unfazed growing in the cracks of sidewalks and pavement. It can grow in rich, fertile soil as well, and so it often makes an appearance in vegetable gardens, agricultural fields, and ornamental garden beds.

Stinking lovegrass growing in a crack between the pavement and the sidewalk

There are dozens of species in the genus Eragrostis, with representatives around the world. A few are native to North America, and a few others have been introduced. Provenance aside, all have the potential to be weedy. Eragrostis curvula, weeping lovegrass, is an aggresive invader in some regions. Eragrostis minor, lesser lovegrass, is similar to stinking lovegrass, not only in appearance but also in its provenance and status as a weed in North America. In Wild Urban Plants of the Northeast, Peter Del Tredici mentions two North American natives that can be weedy along roadsides and in vacant lots, sidewalk cracks, garden beds, and elsewhere: E. pectinacea (Carolina lovegrass) and E. spectabilis (purple lovegrass). Last but not least, Eragrostris tef (aslo known as teff) is a commonly cultivated cereal crop in Ethiopia and surrounding countries, the seeds of which are harvested to make injera.

Additional Resources:

Video of the Week:

The Idaho Weed Awareness Campaign has some fun educational materials, including a few puppets, to help teach children about noxious weeds. Mortie Milfoil is a puppet who helps spread the word about the aquatic invasive, Eurasian watermilfoil (Myriophyllum spicatum). Hannah teaches kids about poison hemlock (Conium maculatum). See Hannah’s video below:

Summer of Weeds: Lambsquarters

Since we seem to be on the topic of edible weeds we may as well discuss lambsquarters, another frequently present and commonly eaten, nutritious and versitile weed. Botanically known as Chenopodium album, it is a member of the family Amaranthaceae and therefore related to several common (and uncommon) agricultural crops, including spinach (Spinacia oleracea), beets (Beta vulgaris), Swiss chard (also Beta vulgaris), amaranth (Amaranthus spp.), and red orach (Atriplex hortensis). Chenopodium, a genus consisting of 100 plus species, is also cultivated in various parts of the world for its edible leaves, stems, and seeds. Chenopodium quinoa, commonly known as quinoa, is now a popular “grain” in North America after being grown for millenia by Andean cultures.

Chenopodium album is a summer annual that reaches up to 6 feet tall with sturdy, angular stems and triangular, diamond-shaped, or lance-shaped leaves with irregularly toothed margins. The leaves are green on top and mealy gray-white on bottom. The flowers are tiny, petal-less, and organized in tight clusters at the ends of branches. In Botany In a Day, Thomas Elpel describes the flowers as “little green ‘globs’ forming along an upright stalk, sometimes colored with specks of yellow.” They are generally wind-pollinated, but are occassionally visited by pollinating insects. Each plant can produce tens of thousands of seeds, which are potentially viable for up to 40 years.

Inflorescence of lambsquarters (Chenopodium album)

Lambsquartes is one of many common names for C. album (others include goosefoot, fat hen, baconweed, mealweed, frostblite, and wild spinach), and is a name with several proposed origins. Is it because the plant is commonly found growing in the manure-rich soils of barnyards? Or is it because the fuzzy undersides of the leaves are reminiscent of sheep’s wool? Perhaps it is because per weight, the harvested plants and a quarter of lamb contain roughly the same amount of protein? Who knows? Despite all this talk of sheep, however, large quantities of lambsquarters are reported to be poisonous to both sheep and pigs.

Though lambsquarters prefers nutrient-rich soils, it tolerates a wide variety of soil types, including dry, compacted, urban soil. It is drawn to all sorts of disturbed sites and is particularly abundant in gardens, agricultuaral fields, and roadsides. It readily hybridizes with other Chenopodium species, including the North American native C. berlandieri. In The Book of Field and Roadside, John Eastman calls it “one of the wold’s most abundant and noxious weeds,” because “it competes with some 40 crops [and] is especially invasive in tomato, potato, sugar beet, soybean, and corn fields.”

Eastman goes on to hint at lambsquarters’ potential for phytoremediation: “The plant accumulates high levels of nitrates and pesticides in addition to its oxalic acid content.” It also takes up heavy metals, including zinc, copper, and lead. This phenomenon is worth a future post, so stay tuned.

Leaf of lambsquarters (Chenopodium album)

That being said, when harvested from a non-polluted site, lambsquarters is a very nutritious spinach-like green both raw and cooked. Younger leaves and plants are preferred because older ones tend to be higher in oxalic acid. The seeds are also edible and, like quinoa, can be used in a similar manner as common grain and cereal crops. Harvester ants and various bird species also collect and consume the seeds. The roots of lambsquarters are high in saponin and can be used to make soap.

There are many reasons to be impressed with Chenopodium album, including its ability to tolerate drougt and frost, its adaptability to all types of soil, its highly nutritious plant parts (but also potentially toxic due to accumalation of pollutants and oxalic acid), and its competitive and persistent nature. Ehrenfried Pfeiffer, author of Weeds and What They Tell, was in awe of this “most enduring annual weed” and its goosefoot family relatives, writing: “We have the feeling that the goosefoot was destined to play a better role than to become an obnoxious weed. They follow closely man’s steps, showing their inclination to be domesticated. Probably future plant breeders may develop new cultivated varieties out of this family long after our present cultivated plants have degenerated, for it is their extreme vitality and preserverence to grow that makes the goosefoot family so interesting.”

Pfeiffer’s predictions haven’t quite come to pass, but time will tell.

More lambsquarters flowers

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According to an article posted on LiveScience, lambsquarters is one of “The Five Healthiest Backyard Weeds.” The list includes two other weeds we have covered during the Summer of Weeds: Purslane and Plantain.

Summer of Weeds: Plantains

This is a revised version of two ethnobotany posts that appeared previously on Awkward Botany: White Man’s Foot, part one and part two. Plantains have a long history of ethnobotonical uses, as well as a bad reputation of being pesky, hard-to-eliminate weeds. The two most common introduced plantain species in North America are broadleaf plantain (Plantago major) and lanceleaf plantain (Plantago lanceolata). Wherever our daily travels take us, chances are there is a plantain growing nearby.

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Plantago major is in the plantain family (Plantaginaceae) a family that consists of at least 90 genera, including common ornamental plants like Veronica (speedwells), Digitalis (foxgloves), and Antirrhinum (snapdragons). The genus Plantago, commonly known as plantains, consists of around 200 species distributed throughout the world in diverse habitats. Most of them are herbaceous perennials with similar growth habits.

Originating in Eurasia, P. major now has a cosmopolitan distribution. It has joined humans as they have traveled and migrated from continent to continent and is now considered naturalized throughout most temperate and some tropical regions. P. major has a plethora of common names – common plantain being the one that the USDA prefers. Other names include broadleaf plantain, greater plantain, thickleaf plantain, ribgrass, ribwort, ripplegrass, and waybread. Depending on the source, there are various versions of the name white man’s foot. Along the same line, a common name for P. major in South Africa is cart-track plant.

common plantain (Plantago major)

Common plantain starts by forming a rosette of broad leaves usually oriented flat against the ground. The leaves are egg-shaped with parallel veins; occasionally, leaf margins are faintly toothed. The inflorescence is a leafless spike up to 20 centimeters tall or taller with several tiny flowers that are a dull yellow-green-brown color. The flowers are wind pollinated and highly prone to self-pollination. The fruits are capsules that can contain as many as 30 seeds; an entire plant can produce as many as 15,000 seeds. The seeds are small, brown, sticky, and easily transported by wind or by adhering to shoes, clothing, animals, and machinery. They require light to germinate and can remain viable for up to 60 years.

Common plantain prefers sunny sites but can also thrive in part shade. It adapts to a variety of soil types but performs best in moist, clay-loam soils. It is often found in compacted soils and is very tolerant of trampling. This trait, along with its low-growing leaves that easily evade mower blades, explains why it is so common in turf grass. It is highly adaptable to a variety of habitats and is particularly common on recently disturbed sites (both natural and human caused). It is an abundant urban and agricultural weed.

Illustration of three Plantago species from Selected Weeds of the United States (Agriculture Handbook No. 366) circa 1970

Even though it is wind pollinated, its flowers are visited by syrphid flies and various bee species which feed on its pollen. Several other insects feed on its foliage, along with a number of mammalian herbivores. Cardinals and other bird species feed on its seeds.

Humans also eat plantain leaves, which contain vitamins A, C, and K. Young, tender leaves can be eaten raw, while older leaves need to be cooked as they become tough and stringy with age. The medicinal properties of  P. major have been known and appreciated at least as far back as the Anglo-Saxons, who likely used a poultice made from the leaves externally to treat wounds, burns, sores, bites, stings, and other irritations. It has also been used to stop cuts from bleeding and to treat rattlesnake bites. Apart from external uses, the plant was used internally as a pain killer and to treat ulcers, diarrhea, and other gastrointestinal issues.

P. major has been shown to have antibacterial, anti-inflammatory, antioxidant, and other biological properties; several chemical compounds have been isolated from the plant and deemed responsible for these properties. It is for this reason that P. major and other Plantago species have been used to treat such a diverse number of ailments. The claims are extensive and worth exploring. You can start by visiting the following sites:

Excerpts about plantains from The Book of Field and Roadside by John Eastman

Concerning their cosmopolitan nature: “Although both plantains [P. major and P. lanceolata] are Eurasian natives, they have long been thoroughly naturalized global residents; the designation ‘alien’ applies to them in the same sense that all white and black Americans are alien residents.”

In which I learned a new term: “Both species are anthropophilic (associate with humans); they frequent roadsides, parking areas, driveways, and vacant lots, occurring almost everywhere in disturbed ground. Where one species grows, the other can often be found nearby.”

Illustration by Amelia Hansen from The Book of Field and Roadside by John Eastman

Medicinal and culinary uses according to Eastman: “Plantains have versatile curative as well as culinary properties; nobody need go hungry or untreated for sores where plantains grow. These plants contain an abundance of beta carotene, calcium, potassium, and ascorbic acid. Cure-all claims for common plantain’s beneficial medical uses include a leaf tea for coughs, diarrhea, dysentery, lung and stomach disorders, and the root tea as a mouthwash for toothache. … Their most frequent and demonstrably effective use as a modern herb remedy, however, is as a leaf poultice for insect bites and stings plus other skin irritations. The leaf’s antimicrobial properties reduce inflammation, and its astringent chemistry relieves itching, swelling, and soreness.”

Even the seeds are “therapeutic”: “The gelatinous mucilage surrounding seeds can be readily separated, has been used as a substitute for linseed oil. Its widest usage is in laxative products for providing bulk and soluble fiber called psyllium, mainly derived from the plantain species P. ovata and leafy-stemmed plantain (P. psyllium), both Mediterranean natives.”

An excerpt from Weeds: In Defense of Nature’s Most Unloved Plants by Richard Mabey

“Plantain, ‘the mother of worts,’ is present in almost all the early prescriptions of magical herbs, back as far as the earliest Celtic fire ceremonies. It isn’t clear why such a drab plant – a plain rosette of grey-green leaves topped by a flower spike like a rat’s-tail – should have had pre-eminent status. But its weediness, in the sense of its willingness to tolerate human company, may have had a lot to do with it. The Anglo-Saxon names ‘Waybroad’ or ‘Waybread’ simply mean ‘a broad-leaved herb which grows by the wayside.’ This is plantain’s defining habit and habitat. It thrives on roadways, field-paths, church steps. In the most literal sense it dogs human footsteps. Its tough, elastic leaves, growing flush with the ground, are resilient to treading. You can walk on them, scuff them, even drive over them, and they go on living. They seem to actively prosper from stamping, as more delicate plants around them are crushed. The principles of sympathetic magic, therefore, indicated that plantain would be effective for crushing and tearing injuries. (And so it is, to a certain extent. The leaves contain a high proportion of tannins, which help to close wounds and halt bleeding.)”

Summer of Weeds: Eating Purslane

If it wasn’t so prolific and persistent, purslane would probably be a welcome guest in our vegetable gardens and edible landscapes. Easily among the most nutritious and versatile of the edible weeds, Portulaca oleracea is an annoyingly abundant annual that has inserted itself into garden beds and croplands in temperate climates across the globe. Thought to have originated in India or somewhere in Eurasia, purslane invaded North America long before Europeans did and has been naturalized across much of the continent for hundreds of years.

common purslane (Portulaca oleracea)

There are over 100 known species in the genus Portulaca, the only genus in the family Portulacaceae (otherwise known as the purslane family). Common purslane is a succulent plant with paddle- or teardrop-shaped leaves that generally grows low to the ground, forming a thick mat. It reaches for the sky when grown in shade or when competing with other plants for space. It produces little, yellow flowers that only open in bright sun and are typically self-pollinated. A small capsule containing dozens of tiny, black seeds quickly follows each flower. Each plant can produce tens of thousands of seeds, which remain viable for around 40 years.

Attempts to remove purslane by cultivation may only aid its survival. Broken pieces of the plant can take root in the soil, and uprooted plants can re-root if they are in contact with soil. Stirring up the ground brings to the surface seeds from purslane’s extensive seed bank. These freshly exposed seeds can then germinate, taking advantage of disturbance and open space. For all these reasons and more, John Eastman writes in The Book of Field and Roadside: “Purslane knows how to live and linger.”

The ever-urban and ever-common purslane.

The seeds of purslane germinate in late spring and throughout the summer when the soil has reached at least 75 – 80° Fahrenheit. It is adapted to high heat and dry soils. In order to conserve water, it switches to CAM photosynthesis when conditions are particularly hot and dry. In this photosynthetic pathway, carbon dioxide is stored as malic acid during the night and then converted back during the day. This means that, when it comes to eating purslane, the flavor changes depending on when the plant is harvested. In The Wild Wisdom of Weeds, Katrina Blair discusses this phenomenon: “In the morning purslane leaves contain as much as ten times more malic acid, making them very sour tasting. If you prefer a milder tasting purslane, harvest your greens in late afternoon and if you want more zing to your recipes, gather the leaves at dawn.”

Speaking of eating purslane, if all the claims are to be trusted, there may not be a more nutritious weed. In A Feast of Weeds, Luigi Ballerina calls it “a health bomb” because “it contains more omega-3 fatty acids than almost any other green, not to mention vitamins A, B, and C and beta carotene.” Blair calls it “one of the most nutritious plants on Earth,” and goes on to sing praises about its richness in dietary fiber, vitamins, minerals, protein, etc. Funnily enough, in describing the health benefits of purslane, Ballerina also quotes ancient sources claiming that “purslane calms sexual excitement.” Apparently it not only “eliminate[s] sensual dreams, but if used too much, it often extinguishes all ardor and even the capacity to procreate.”

With that caveat in mind, I tried it anyway. I had eaten it before, but nothing more than a leaf here and there and once in a green salad. I picked two recipes to try: Walnut Purslane Coleslaw from The Wild Wisdom of Weeds and Potatoes and Purslane from A Feast of Weeds. I’m generally a big fan of coleslaw, but for whatever reason I found this recipe to be a little bland. It was missing something, but I couldn’t put my finger on it. The purslane seemed to add a vague slimy-ness to it, which it will do on account of its mucilaginous nature.

Walnut Purslane Coleslaw

The Potatoes and Purslane recipe involved cooking the purslane. I enjoyed the finished product both hot and cold. The purslane added a sort of lemon-y spinach flavor. Those who tried it with me also liked it. The potato recipe was made with purslane that had been harvested in the morning, which may explain the strong lemon-y flavor. The coleslaw was made with purslane harvested in late afternoon, which may explain its blandness. I will have to try it the other way around for comparison. Purslane recipes abound in books and on the internet; browsing through them, I am intrigued enough to consider trying others. I think I’ll start with pickled purslane, purslane pesto, and perhaps, purslane sauerkraut.

Potatoes and Purslane

More Resources:

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Do you have a favorite purslane recipe? Share it in the comment section below.