My book is out! It showed up a week earlier than expected, a pleasant surprise for anyone who pre-ordered a copy. Common Backyard Weeds of the Pacific Northwest is available now from your favorite bookseller. You can also order it directly fromthe publisher or through my Bookshop store. Thank you for your support! If and when you get your hands on a copy, please tell me what you think. Constructive feedback would be particularly helpful so that I can make improvements to the second edition. (Yes, I’m already planning on a second edition, and I already have a few edits of my own!)
While researching this book, I came across many new and interesting facts about weeds that I didn’t previously know. It’s part of the joy of writing. Some of these discoveries pertain to cocklebur, a prickly and troubling weed with a fascinating dispersal story. Xanthium strumarium is a widespread plant that comes up in farms, rangelands, wetlands, yards, vacant lots, roadsides, ditch banks, and a variety of other locations. In the book I introduce it this way: “A native and/or introduced annual (short-lived perennial) that grows up to 4 feet tall with either a single or a few rigid stems.” It produces a thick, woody taproot and has broad, simple leaves. Separate male and female flowers occur on the same plant, and the flowers are wind-pollinated and predominantly self-pollinated – a unique state of affairs for a plant in the aster family.
fruits of cocklebur (Xanthium strumarium)
The most recognizable feature of cocklebur are the fruits, which are egg-shaped and covered in hooked prickles. One of their dispersal mechanisms is immediately obvious, grabbing onto passers-by and hitching a ride. Since they are often found near waterways or in areas where flooding occurs, another way they are dispersed is by floating in water. Both of these dispersal pathways allow seeds to travel long distances.
Still, cockleburs have another trick up their sleeves that helps ensure their longevity. Inside each fruit there are two seeds which look a bit like oversized sunflower seeds. These seeds exhibit something called somatic polymorphism. This term can mean different things depending on the plant, but in cocklebur’s case it means that the two seeds have different dormancies. One seed will germinate within the first year. The second seed remains dormant for at least a year and can germinate much later. A classic example of bet hedging. The two seeds are equipped with a water-soluble germination inhibitor. Oxygen degrades the inhibitors which leads to germination, but this happens at a different rate in each of the two seeds. (Read more about this here.)
inside the fruit of a cocklebur
From a weed management perspective, dispersal mechanisms and seed viability are two critical traits to become familiar with. When you know how your weeds get around and how long their seeds might last in the soil, you can make informed decisions on which weeds to remove and when. Just another reason to get my book!
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If you are in the Boise area, I will be at Rediscovered Books this Saturday (July 11,2026) for a short presentation and book signing. Goherefor more details. Follow me on Instagram to stay informed on this and future book events. Hope to see you there!
If you’re reading this the day it’s posted, we are two weeks away from my book being released. Common Backyard Weeds of the Pacific Northwest will be available for purchase from your favorite bookseller on July 7, 2026. The book is a quick guide to many of the common weeds you will find across Idaho, Oregon, Washington, and parts of British Columbia and Alaska. It’s small enough to fit in your pocket and approachable enough for those who know nothing about plants to get something out of it. My hope is that it has something to offer plant people too. Preorder now to be sure you’ll get a copy. I appreciate the support!
A few more details about the book. The introduction defines weeds, gives a broad overview on how to identify plants, and shares some basic information on how to manage weeds. The weeds themselves are organized into general life forms: low-growing, upright broadleaf, vining, and grass or grass-like. The book does not cover trees, shrubs, or aquatic weeds. Plant profiles include a brief introduction, habitat preferences, plant descriptions, and some look-alikes. There is also some general guidance on how to manage the weed along with a sentence or two on how to use them (ethnobotany!) or how they might be used (wildlife or ecological value!). Photos are included to help with identification, and resources are listed to keep you learning.
Some of the profiles in the book cover multiple weeds in one. This is because their life histories, life forms, and habitat preferences are very similar. Their management is also identical. While I typically recommend identifying your weeds before making management decisions, closely related weeds that act similarly don’t necessarily need to be identified precisely to species. However, if you’re a plant identification dork like me, figuring out exactly what species of weed you have is a thrilling endeavor. In fact, something I often say is if you’re looking to get better at plant identification, start with weeds. There are so many resources out there for identifying weeds (like my book!), that studying descriptions of weeds makes for a great introduction to the basics of plant identification.
As an example, let’s look at two different weedy, annual sowthistles: spiny sowthistle (Sonchus asper) and common sowthistle (Sonchus oleraceus). Both of these species can look very similar, from their flowers to their growth forms to their leaves and stems. One way to easily tell them apart is by closely observing their leaves, specifically their leaf bases. The leaf bases of both species clasp the stem. The leaves of spiny sowthistle tend to be glossy with more spines along their margins. Their bases are open and rounded, creating a distinct spiral form. The leaf bases of common sowthistle are folded over, which can give them a pointed look.
leaf bases of spiny sowthistle (Sonchus asper)
leaf bases of common sowthistle (Sonchus oleraceus)
Another similar looking, related species is perennial sowthistle (S. arvensis). It is relatively easy to tell apart due to its perennial nature and its rhizomatous root system. Managing a perennial weed that spreads by rhizomes can be more of a challenge and may require different strategies compared to annual weeds with simple root systems. Understanding the life histories and growth habits of your weeds will make you better equipped to manage them, and hopefully my upcoming book will help you do that.
When garden plants go weedy, it doesn’t necessarily mean they’ve escaped the boundaries of our yards and invaded nearby natural areas or uncultivated spaces. While this is a concern for a significant number of ornamental plants, sometimes the weediness of a garden plant is experienced within the very yard or garden it was planted in. For some of us, such a plant’s weediness can turn us off from growing it at all. We opt to weed out the overzealous plants and replace them with something tamer. Others may decide to just put up with this behavior. Perhaps we like the plant too much to get rid of it, so we simply accept its overly competitive nature. We may even welcome its ability to take any and all available ground. Why toil away trying to get something else to grow, when our weedy friends take up space with little to no effort on our part?
This seems to be the story of violets. While certainly not all violets exhibit this behavior – some species are actually downright difficult to grow – there are a select number of species that are proficient at propagating themselves and spread readily. They capitalize quickly on open ground and set up shop before anything else has the chance. Given the opportunity, they may even snuff out other plants and take their place. I’ve dealt with the latter myself, as violets moved in on some mat-forming penstemons and eventually took them out.
While violets can and will act aggressively in garden beds, ire towards their unruly behavior seems to stem largely from their activity in lawns. There is an expectation that lawns be grass species only, and any other plant that finds its way in gets labeled as an intruder that must be stopped. While some people tolerate (and even encourage) a few guests – which I think is a reasonable approach – others prefer grass and grass alone. Whatever your preference is, violets can become too much. Grass often has a difficult time competing with the broad, evergreen leaves of violets and their horizontally spreading rhizomes and stolons. As violet colonies expand, the grass succumbs, and broad patches of violets can become dominant in declining lawns.
At least three species of violets are particularly notorious for invading lawns in North America: Viola odorata, Viola sororia, and Viola riviniana. Sweet violet, or V. odorata, is a perennial plant from Eurasia that forms dense mats with the help of rhizomes and leafy stolons. Its leaves are oval to heart-shaped with toothed margins. Solitary flowers rise above the foliage on slender, hooked stalks. Flowers are white to various shades of purple and have a sweet scent. Common blue violet, or V. sororia, is native to North America and looks very similar to sweet violet. The two species can also hybridize. Common blue violet tends to have more heart-shaped leaves and broader flowers. It also produces only rhizomes, no stolons.
Dog violet or wood violet (V. riviniana) is another similar-looking plant from Eurasia that – depending on what source you reference – either does or does not spread by stolons. This confusion could arise if sprawling stems are rooting at the nodes and being mistaken for stolons, which almost seems like a distinction without a difference. If you’ve seen this plant in a garden setting, there is a good chance it is the commercially popular, purple-leaved form (V. riviniana Purpurea Group).
All of these violets flower in the spring, and sometimes resume flowering in the fall. Their fruits are capsules, which upon ripening split open and fling out several tiny, shiny seeds. There ability to spread readily both by seed and vegetatively is a reason they are so successful at getting around. And if that weren’t enough, they have a secret weapon called cleistogamous flowers. These are flowers that never open for cross-pollination. Instead, they remain closed and opt for self pollination. Their fruits ripen, split open, and release seeds, often coming equipped with elaiosomes – a little packet of food that encourages seed dispersal by ants. These cleistogamous flowers appear in late summer/early fall and are hidden below the foliage either at or below the soil. With so many options for reproduction and dispersal, its easy to see why lawn violets can frustrate many gardeners.
Viola riviniana Purpurea Group
Lawn invaders invade lawns because they are adapted to the conditions found there. Lawns are often well-watered, so the soil stays moist. The soil is also generally compacted due to regular foot traffic, etc. Plants with low growing foliage escape the blades of mowers, which would kill or set back other weeds with more upright foliage and stems. These are all reasons why violets take well to turfgrass. They tend to prefer shady, cool, moist locations, but can also tolerate full sun and dry soils. Once they have gained footing in a shady part of the lawn, their superb ability to reproduce and spread allows them to expand their territory, particularly in lawns that are poorly maintained. Luckily, their roots are shallow and the plants are easy enough to dig up and remove. If you are tenacious enough, they can be largely eliminated. Or, just learn to accept their presence and appreciate them for their carpet of attractive flowers in the spring and their broad, evergreen leaves year-round. It could be worse.
Prunella vulgaris can be found all over the place. It has also been used to treat just about everything. What else would you expect from a plant known commonly as self-heal, heal-all, all-heal, and woundwort? The medicinal value of this plant has been appreciated for centuries across its expansive range, and studies evaluating its medicinal use continue today. Being such a ubiquitous species – both as a garden plant and a native plant (and also a common weed) – and because it has so much clout in the world of herbal medicine, it’s an obvious candidate for Tea Time.
Self-heal is a member of the mint family (Lamiaceae), easily distinguished by its square stems, opposite leaves, and bilabiate and bilaterally symmetrical (or zygomorphic) flowers. One surprise is that, unlike the many aromatic members of this family, the foliage of self-heal lacks a strong scent. P. vulgaris occurs naturally across Asia, throughout Europe, and in parts of northern Africa. It is also widely distributed across North America. Apart from that, it has been introduced to many regions in the southern hemisphere and has also been frequently moved around throughout its native range. Eurasian varieties now intermingle with North American varieties, which can make it difficult to determine a native individual from an introduced one.
self-heal (Prunella vulgaris)
Self-heal is an adaptable plant that tends to prefer shady, moist locations, but can also be found in open, dry, sunny sites. Find it along forest edges, roadsides, ditches, and trails, as well as on the banks of streams, lakes, and reservoirs. It occurs in gardens, both intentionally planted and as a weed, and can escape into lawns, vacant lots, and open fields, as well as into nearby natural areas.
P. vulgaris is an evergreen that grows both prostrate and upright, sometimes reaching 1 foot tall or more (but is often much shorter). It has shallow, fibrous roots, and its stems root adventitiously as they sprawl across the ground, frequently forming an extensive mat or groundcover. Its leaves are oval to lance-shaped and measure about one inch long. Lower leaves have petioles, while upper leaves may become stalkless. Leaf margins are entire or can be slightly toothed. As plants age, they can develop a coppery or purple-bronze color.
the leaves of self-heal
The flowers of self-heal are generally a shade of purple, but can also be white, pink, or blue. They bloom irregularly in a spike measuring up to two inches long. Flower spikes are thick, dense, cylindrical, and made up of whorls of sharp-pointed bracts. Flowers bloom irregularly along the spike and occur from late spring/early summer into the fall. Each flower produces four nutlets, which sit within a cup-shaped, purple calyx.
As a medicinal herb, self-heal has been used both internally and externally to treat a long list of ailments. These include sore throats, diarrhea, fevers, intestinal infections, liver problems, migraines, heart issues, dermatitis, goiter, and thyroid disfunction, just to name a few. It has been used topically to treat skin irritations, bites, stings, and minor cuts and scrapes. This is thanks to its antimicrobial properties and its ability to stop bleeding. A report in the journal Pharmaceuticals (2023) calls P. vulgaris an “important medicinal plant” due to its “rich chemical composition” and its “pharmacological action.” Chemical analyses find the plant to be a valuable source of phenolic compounds, flavonoids, rosmarinic acid, and ursolic acid, among numerous other compounds. If you are curious to learn more detailed information regarding this plant’s medicinal value, you can refer to the above report, as well as one found in Frontiers in Pharmacology (2022).
self-heal tea
P. vulgaris is an edible plant, and its young leaves can be eaten raw or cooked. The leaves together with the flowers can also be dried and used to make a tea. This is how I had it. I used about two teaspoons of dried leaves to one cup of water. Feel free to use more if you would like. I thought the tea was pretty mild. It had a slight sweetness to it and a hint of mint flavor. It has been described as bitter, but I didn’t find it to be overly so (although I may have a higher tolerance for bitterness). Sierra tried it and said that it tasted like “water left over from something else.” That might be because it was more diluted than she would have preferred. Overall, I thought it was a pleasant experience and would be happy to drink it again.
In case I need a reminder that the horticulture industry has a history of introducing weedy plants to natural areas, I get one each time I bike to work. Riding along the Boise River Greenbelt, a trail that for much of its length is flanked by cultivated landscapes on one side and a highly modified but largely naturalized river bank on the other, I see a mixture of both native and introduced plants. Of the introduced plants, many are horticultural species that have escaped cultivation and established themselves on the bank of the river. There are catalpa and black locust trees brought in from the other side of the country, St. John’s wort and chicory from Eurasia, honeysuckles primarily from Asia, and a few different cherry species and hybrids with varied provenances. And this is just a small sample of what can be found along my three and a half mile bike ride.
St. John’s wort (Hypericum perforatum) on the banks of the Boise River
This is certainly not a new concern. We have been aware of the role that horticulture plays in introducing invasive species for quite some time now. Several years back, while doing a deep dive into the topic of invasive species, I wrote about this issue right here on this very blog. According to a study published in Frontiers in Ecology and the Environment (2021), out of 1285 plant species identified as invasive, 61% are currently sold in nurseries. If that’s not concern enough, an additional factor to consider is climate change. Plants that were less likely to escape cultivation and head for the wild, may take the opportunity to do so in a changing climate. Plus, horticultural plants that are already problems in certain areas could expand their range as climates become more favorable in new locations, especially if these plants continue to be sold in nearby nurseries.
These concerns and more are the topic of a paper published in BioScience (2023). Evelyn M. Beaury, et al. looked at nurseries across the United States and the plants they sell in order to determine where invasive plants are still being sold in regions where they are invasive. Additionally, they looked at plants known to be invasive but that are not currently invasive in the regions they are being sold. Using climate models, they predicted whether or not these plants could become invasive under changing climates.
Plants are being moved around with a lot more ease than they once were, and the sales of problematic plants are increasingly difficult to regulate. For one thing, plants prohibited for sale in one state can be purchased at nurseries in neighboring states and brought back to be planted in regions where those plants are invasive. And while mail order has existed for a long time, online ordering makes the process even simpler; and many online plant vendors are not liscensed nurseries, making them much more difficult to regulate. But even regulation is typically a response to something that has already become a problem, rather than a proactive measure to prevent plants from escaping into natural areas.
Beaury, et al. identified 672 nurseries across the United States, both online and traditional retailers. Each of these nurseries were selling one or more of the 89 plant species that became the focus of their research. These are plant species that are either on federal or state noxious weed lists or that have been identified as invasive by Invasive Plant Atlas. The reach of each nursery was determined by using customer reviews to compute distances that plants might travel after being purchased at nurseries or from online stores. Obviously, not every customer that purchases a plant leaves a review, but this is a good way to get a general idea how far away customers are from nurseries without having access to more detailed records. These geotagged reviews can also be cross-referenced with known distributions of invasive plants. Using climate models and environmental predictor variables, the researchers determined areas of current and potential invasion for each of the 89 plants.
tansy(Tanacetum vulgare) – one of the 89 plant species looked at in the study
The first question was about proximity to current records of plant invasions. Results showed that “49 of the 89 ornamental invasives were sold within 21 kilometers (13 miles) of an observed record of invasion.” When invasive plants are sold and planted near locations where they are already known to be invasive, it gives them the opportunity to add new plants to existing or developing invasions. In ecology, this is known as propagule pressure. When it comes to current and future climate, most species in the study are being sold by nurseries where the climate is either currently favorable for range expansion or may eventually become favorable. Specifically for future climate, 40 of the 89 plants are being sold in regions that are currently suitable for invasion and will continue to be suitable as the climate changes, and 25 of the 89 plants are being sold in regions where the climate is currently unsuitable but will become suitable as temperatures warm.
Particularly for plants being sold in areas that are not yet suitable for invasion, there is time to educate both the nursery industry and the general public and to look for alternatives to these plants. However, as the researchers point out, their analysis “only examined about 10% of the larger pool of U.S. ornamental plants known to be invasive,” and they “sampled only a subset of the nurseries that could be selling invasive species in the United States.” It is highly likely that the results of this study are an underestimation of the problem. Clearly the work of education and finding alternatives to problematic plants is monumental. The hope is that studies like this can help with education and can assist with working out ways to regulate sales of invasive plants.
coltsfoot(Tussilago farfara) – another one of the 89 plant species looked at in the study
Regulating the sale of plants is beyond most of our control, and how much regulation we should be enforcing on nurseries in the first place is a debate we should be having. Outside of those questions, there is a responsibility that we should take as gardeners and as residents of the planet. If we choose to grow plants, it is crucial that we get to know them. We should be taking the time to observe the degree to which they spread and how they are being dispersed. When they do move around our yards, where are they going, and are they able to grow outside of our care? Are they leaving our properties and coming up elsewhere? If we choose to plant non-native species, we should be mindful of how they might affect nearby, wild landscapes if they were to escape our yards and establish themselves in these locations. We should also be aware of where we live in the city. If our gardens are in the middle of a dense urban landscape, perhaps there is less concern that our plants will move beyond the borders of our gardens. But if we garden near natural areas, we should be significantly more selective about the things we plant, and we ought to be more observant as to what those plants are up to.
Nurseries generally sell the plants that gardeners want to buy, which means we can choose not to buy problematic plants and instead demand alternatives to these plants. Seeking out nurseries that sell the types of plants that are better suited for our regions and do not exhibit invasive behaviors can send a message to other growers that they should phase out certain plants and start growing the plants that gardeners are asking for. This may be a simplistic take, and as with most things, it’s complicated. While one of the goals of this research is to help influence regulators, another goal is simply to “[share] information about high-risk ornamental invaders across states and regions, and [work] with horticulture and community members to reduce the escape of ornamental species into natural areas.” This is precisely the area where gardeners can make a difference.
On that note, I will be starting a new series of posts to discuss some of the ornamental species that have gone weedy. By getting to know the plants that find themselves in this predicament, we can be better situated to make informed decisions about what to do about them.
Happy 2025! Apparently it’s time for another year in review. As I said in last year’s review, 2024 was going to be another year of pollination, in which I would write monthly posts on the topic of pollination. Well, clearly that didn’t happen. After two posts, I dropped the ball. That’s okay though. Another Year of Pollination will continue indefinitely. As it is, I essentially stole the name, Year of Pollination, from a podcast called Year of Polygamy, which after starting in January 2014, continues to put out episodes a decade later. A “year,” as it turns out, can also be a period of indefinite length.
2024 wasn’t the most fun year I’ve ever had. I’m actually happy to see it go. Hoping for bigger and better things in the year to come. However, one very exciting piece of news came near the end of the year, which I hinted about in this post. The past couple of months have been a bit of a blur as I have been writing furiously about weeds for a book project that should come out sometime in 2026. Something to look forward to. It is focused specifically on the Pacific Northwest, so if there are any weeds-interested people in the area that would like to help out in some way with this project, please reach out.
The book will keep me busy for a good part of the year, so I don’t anticipate being able to post a whole lot more here than I have in the past couple of years. But I’ll see what I can do. Be in touch either way. All the social media links and ways to support Awkward Botany can be found on this link tree. Thank you, as always, for reading and nerding out about plants with me. See you in 2025!
Most of the posts this year were part of ongoing series. So, here they are:
Why has this blog been so quiet lately? There are plenty of excuses for that. It doesn’t really matter either way, but since we’re on the subject, one thing that has kept me occupied recently is being back in school. I’m working on a certificate in GIS, and I’m hoping to make some cool maps. More on that later perhaps.
For now, I thought I’d share one of my final projects. I figured it was a good excuse to use something I’ve already been working on – namely, Weeds of Boise – and apply it to one of my GIS classes. If you’ve been following Weeds of Boise, not much here will be new. Except the interactive maps!
Using observations from iNaturalist, I created three different maps of weeds found around Boise. I published them, using ArcGIS StoryMaps, alongside more of my usual pontificating about weeds and urban areas, etc. The maps aren’t perfect, but they opened up some interesting possibilities for what Weeds of Boise might become. Something to explore further in the future.
When you make yourself the weeds guy, and the word gets out that you’re the guy to go to when it comes to weeds, invitations and inquiries start coming your way. Usually it’s just someone asking you to identify a weed or telling you how much they despise a particular plant for its weedy behaviors. Sometimes it’s writing a weeds-themed article or teaching a class about weeds. It can even be an invitation to go on a weeds walk and be interviewed for a television series. This time it’s something, perhaps, a bit bigger.
I won’t say too much about what the project is at this point. It’s a little too early in the process for the big reveal. However, I will say that it involves at least two things: weeds and the Pacific Northwest. That’s partly why I’m bringing this up.
Do you live in the Pacific Northwest? Would you be interested in talking about weeds sometime? If you’re reading this, and you think you might have some input on the subject, please let me know. You can get in touch using the contact form or by sending me a direct message on Instagram. I can give you more information at that point, and we can determine if there is a way you can help.
There will be more to come about this exciting new project in the near future. Meanwhile, my lack of posting, which you may or may not have noticed, is likely to continue for a while. Summers get pretty busy around here, and as much as I’d like to share more posts with you, it just doesn’t happen. The fact that I’m basically back in school for a couple semesters, along with this new opportunity that I’m not saying much about, has made it so that focusing on the blog isn’t getting much easier. But I’ll do what I can, and I’ll try to stay active on Instagram and other social media sites to (sort of) make up for it.
Thanks, as always, for your support, and thank you for putting up with this announcement about an upcoming and soon to be announced announcement.
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Boise’s summers are decidedly hot and dry. Months can pass without any measurable precipitation, meanwhile temperatures regularly peak in the 90’s. In the heat of the summer, multiple days in a row above 100 degrees Fahrenheit is not unheard of. Under these conditions, irrigation is a must if you intend to keep plants alive, particularly plants not adapted to our climate. Skipping out on watering or having something go awry with the irrigation system quickly becomes noticeable as the soil goes bone dry and plants begin to wither away. If this goes on for too long, many plants will not recover, including established trees and shrubs. However, the toughest plants among us, particularly the weeds, will move in to take their place.
You can see an example of this at the United States Postal Service building at 13th Street and Shoreline Lane in Boise, Idaho. The islands in the parking lot are not being watered, which has clearly been the case for quite some time because even the trees and shrubs are dying off. Apart from occasional mowing, very little maintenance is occurring, and our wild urban flora is about all that remains.
parking lot island at the corner of 13 Street and Shoreline Lane
Parking lots are not ideal locations for growing plants. Asphalt and cement dominate – two major contributors to the urban heat island effect – and automobile pollution is concentrated on account of all the cars coming and going on a regular basis. Many parking lots include islands where plants (often poorly maintained), along with other features like signs and lights, are placed. In general, these islands are far too small for trees, but trees are planted nonetheless in a desperate attempt to shade these formidable environments. In locations where snow is common, the snow from parking lots is often piled up on these islands to clear room for cars, while road salts and other ice melts are heavily applied in order to keep people and cars from sliding around. Parking lot plants have to endure all this and more, so it’s no surprise that they usually look pretty rough.
The stresses of added heat, pollution, trampling, and poor care are enough for plants to put up with. Cut off their irrigation supply, and parking lot plants are sure to give up the ghost. A situation like this is an excellent place to familiarize yourself with your wild urban flora. Many weeds seemingly have no problem tolerating these conditions. To demonstrate this, I inventoried the weeds found in neglected parking lot islands at the post office on 13th Street and Shoreline Lane. What follows are a few photos and a list of the weeds I’ve identified so far. Like all posts in the Weeds of Boise series, this list may be updated as I continue to check back in on this location.
spring draba (Draba verna)
shepherd’s purse(Capsella bursa-pastoris)
dandelion(Taraxacum officinale)
black medic(Medicago lupulina)
crabgrass(Digitaria sanguinalis)
annual sow thistle (Sonchus oleraceus)
snag (aka standing dead tree) at post office on 13th Street
Anthriscus caucalis (bur chervil)
Bromus tectorum (cheatgrass)
Capsella bursa-pastoris (shepherd’s purse)
Ceratocephala testiculata (bur buttercup)
Chondrilla juncea (rush skeletonweed)
Claytonia perfoliata (miner’s lettuce)
Convolvulus arvensis (field bindweed)
Conyza canadensis (horseweed)
Digitaria sanguinalis (crabgrass)
Draba verna (spring draba)
Elymus repens (quackgrass)
Epilobium ciliatum (willowherb)
Erodium cicutarium (redstem filare)
Euphorbia maculata (spotted spurge)
Holosteum umbellatum (jagged chickweed)
Hordeum jubatum (foxtail barley)
Lactuca serriola (prickly lettuce)
Lamium amplexicaule (henbit)
Malva neglecta (common mallow)
Medicago lupulina (black medic)
Parthenocissus quinquefolia (Virginia creeper)
Poa annua (annual bluegrass)
Polygonum aviculare (prostrate knotweed)
Portulaca oleracea (purslane)
Senecio vulgaris (common groundsel)
Sonchusoleraceus (annual sow thistle)
Taraxacum officinale (dandelion)
Tragopogon dubius (salsify)
Tribulus terrestris (puncturevine)
Trifolium sp.(clover)
Where there are parking lot islands, there are bound to be weeds whether the islands are being maintained or not. What have you found growing in the parking lot islands in your city? Feel free to share in the comment section below.
In part one of this two part series, I introduced you to the Boise State University campus, located in the heart of Boise, Idaho. I’ve been spending the past year walking the campus and cataloging the weeds that I find there. Boise has a fairly mild climate compared to the rest of Idaho, so weeds are generally easy to find just about any time of year. What weeds are present depends on what time of year it is. To get a complete picture of the suite of weeds that can be found on a site, it’s important to make observations throughout the year. Weeds can also come and go, with certain species becoming more abundant in some years than others, so making observations over multiple years also helps. This is why I try to update posts that are part of the Weeds of Boise series as I make return visits and encounter additional weed species.
What follows is the second half of the list of weeds I’ve documented so far at Boise State University. I’m including a photograph for each month of the year (July – December), as well as a list of what I’ve encountered up to this point. I’m also including a list of weeds that I didn’t come across but that are documented on iNaturalist.
birdsfoot trefoil (Lotus corniculatus) at BSU in July 2023
yellow nutsedge (Cyperus esculentus) at BSU in August 2023
velvetleaf (Abutilon theophrasti) at BSU in September 2023
chicory (Cichorium intybus) at BSU on October 2023
puncturevine (Tribulus terrestris) at BSU in November 2023
bull thistle (Cirsium vulgare) at BSU in December 2023
Additional weeds found on the BSU campus from July – December 2023:
Abutilon theophrasti (velvetleaf)
Cichorium intybus (chicory)
Cirsium vulgare (bull thistle)
Cyperus esculentus (yellow nutsedge)
Eragrostis cilianensis (stinking lovegrass)
Lotus corniculatus (birdsfoot trefoil)
Medicago sativa (alfalfa)
Melilotus alba (white sweetclover)
Solanum nigrum (black nightshade)
Sonchus asper (prickly sowthistle)
Tribulus terrestris (puncturevine)
Additional weeds observed on the BSU campus by iNaturalist users as of December 2023:
awkward botany 