The Life Cycle of a Sunflower Stem Weevil

Last summer I came across a downy woodpecker hammering away at the stalk of a sunflower. I wondered what it was going after, and so I split open a stalk lengthwise to find the center of the stem hollowed out and several small larvae squirming through the debris left behind. A quick internet search later and I was learning about sunflower stem weevils, specifically Cylindrocopturus adspersus, which seems to be the species getting the most attention online and the stem-dwelling weevil that commercial sunflower growers seem most concerned about.

However, the range of sunflower stem weevil doesn’t appear to extend into Idaho, and so this is not likely to be the larvae I was seeing. There are other weevil species whose larvae can be found inside the stems of sunflowers, such as the cocklebur weevil (which is found in Idaho), but since larvae can be difficult to identify, I’ll wait to confirm the identity until I hear from an expert, find an adult weevil, and/or raise the larvae in captivity and see what it turns into. If and when that happens, I’ll be sure to update you. Until then, I present to you the life cycle of a sunflower stem weevil, which is still quite interesting, even if it’s not the species I found inside my sunflower stalks.

Sunflower stem weevils are in the family Curculionidae, which is the snout and bark beetle family. There are tens of thousands of species of weevils, a handful of which interact with sunflowers (plants in the genus Helianthus). Some weevil species eat the seeds, others eat the leaves, some are root feeders, while others are stem feeders. Depending on the life stage of a particular weevil species, it may consume multiple parts of a sunflower. Another interesting weevil is the sunflower headclipping weevil, which you can read about at The Prairie Ecologist.

Adult sunflower stem weevils are about 3/16 inch (4-5 mm) long and somewhat egg or oval shaped. They are grayish-brown with white spots. Their eyes, antennae, and snout are black, and their snout is short, curved, and held beneath the head. As adults, they can be found on sunflowers and sunflower relatives eating the leaves. However, they are not easily found. Their size, for one, makes them difficult to see, and they also move to the opposite sides of leaves and stems when disturbed, sometimes dropping to the ground as a threat approaches. You can see images of them on BugGuide.

unidentified larva in a sunflower stem

The larvae of sunflower stem weevils are about a quarter of a inch long and creamy white with a small, brown head capsule. They feed in the vascular tissue of sunflower stalks during the summer. In the fall, they migrate to the base of the stalks and create chambers in the woody tissue of the stalks and root crowns for overwintering.

Sunflower stem weevils have a single generation per year. After overwintering as larvae in the base of last year’s sunflowers, they pupate and emerge as adults in late spring or early summer. They find young sunflower plants and begin feeding on the leaves. After about 2-4 weeks, the weevils mate and lay eggs just beneath the epidermis of sunflower stems, usually in the stalk just below the cotyledon leaves. The eggs hatch a short time later and begin feeding in the stem until it’s time to overwinter.

the life cycle of a sunflower stem weevil

The damage caused by sunflower stem weevils is generally only a problem on sunflower farms, and only when weevils are found in high enough numbers to cause significant yield losses. Damage to leaves by the adults isn’t usually a concern. On the other hand, as the larvae tunnel through the stem, they can cause the plant to lodge (i.e. fall over prematurely), which is a problem particularly when the plants are machine harvested. Sunflower stem weevils can also introduce and help spread a fungus that causes black stem rot.

Read More About Sunflower Stem Weevil and Other Insect Pests of Sunflowers:

Eating Weeds: Cleavers Coffee

One of the world’s most beloved beverages comes from a species of plant found in the fourth largest family of flowering plants. Rubiaceae, also known as the coffee or bedstraw family, consists of around 13,500 species, placing it behind just Asteraceae, Orchidaceae, and Fabaceae for the most number of species. Coffea arabica, and other species in the genus Coffea, are grown for their fruits which are used to make coffee. This makes Rubiaceae one of the most economically important plant families. A family this size is bound to be home to a weed or two, and in fact, one of the most widespread and obnoxious weeds is also a member of Rubiaceae.

Galium aparine, known commonly by a slew of names including cleavers, occurs naturally across large portions of Europe, Asia, North Africa, and possibly even parts of North America. It has been introduced as a weed in many locations across North America, South America, Australia, New Zealand, Japan, and parts of Africa. It is of particular concern in agricultural settings where its lengthy, sprawling branches and sticky leaves get tangled up in harvesting equipment, while its tiny, prickly fruits get mixed in with seeds of similar size like canola.

Galium aparine

Sticky willy, as it is also known, is an annual plant that, in some cases, can have two generations per year – one in the spring (having germinated the previous fall) and one in the summer. Its stems are square, though not as sharply square as plants in the mint family, and can grow to around six feet long. They are weak, brittle, and don’t stand upright on their own; instead they are found scrambling across the ground or, when given the opportunity, climbing up the lengths of other plants in order to reach the sunlight. Leaves occur in whorls of six to eight and are simple and slender with entire margins. Flowers are produced at leaf axils along the lengths of the branches and are tiny, four-petaled, star-shaped, and greenish white. Fruits are borne in pairs and are round, single-seeded, indehiscent nutlets. The stems, leaves, and fruits are covered in stiff, hooked hairs or trichomes, earning it other names like catchweed bedstraw, grip grass, stickyweed, and velcro plant.

flowers and immature fruit on Galium aparine

Galium aparine is a climbing plant, but unlike other climbing plants, it doesn’t twine up things or produce structures like tendrils to hold itself up. Instead, its ability to climb is made possible by its abundant bristly hairs. A paper published in Proceedings of the Royal Society B (2011) investigates the way G. aparine climbs up other plants using the hairs on its leaves. A close inspection of the leaves reveals that the trichomes on the top of the leaf (the adaxial leaf surface) differ significantly from those found on the bottom of the leaf (the abaxial leaf surface). Adaxial trichomes curve towards the tip of the leaf, are hardened mainly at the tip, and are evenly distributed across the leaf surface. Abaxial trichomes curve towards the leaf base, are hardened throughout, and are found only on the midrib and leaf margins.

Having different types of hairs on their upper and lower leaf surfaces gives cleavers an advantage when it comes to climbing up neighboring plants. The authors of the paper describe the technique as a “ratchet mechanism.” When the upper surface of their leaf makes contact with the lower surface of another plant’s leaf, the flexible, outwardly hooked trichomes inhibit it from slipping further below the leaf and allow it to easily slide out from underneath it. When the lower surface of their leaf makes contact with the upper surface of another plant’s leaf, the stiff, inwardly hooked trichomes keep it attached to the leaf even if the other leaf starts to slip away and allows it to advance further across the leaf for better attachment and coverage. Using this ratchet mechanism, cleavers climb up the leaves of other plants, keeping their leaves above the other plant’s leaves, which gives them better access to sunlight. The basal stems of cleavers are highly flexible, which keeps them from breaking as the plant sways in the wind, tightly attached to their “host” plant.

fruits of Galium aparine

The hooked trichomes on the tiny fruits of cleavers readily attach to the fur and clothing of passing animals. The nutlets easily break free from the plants and can be transported long distances. They can also be harvested and made into a lightly caffeinated tea. Harvesting the fruit takes time and patience. I spent at least 20 minutes trying to harvest enough fruits for one small cup of cleavers coffee. The fruits don’t ripen evenly, and while I tried to pick mostly ripe fruits, I ended up with a selection of fruits in various stages of ripeness.

To make cleavers coffee, first toast the seeds for a few minutes in a pan heated to medium high, stirring them frequently. Next, grind them with a mortar and pestle and place the grinds in a strainer. Proceed as you would if you were making tea from loose leaf tea.

The toasted fruits and resulting tea should smell similar to coffee. The smell must not be strong, because my poor sense of smell didn’t really pick up on it. The taste is coffee-like, but I thought it was more similar to black tea. Sierra tried it and called it “a tea version of coffee.” If the fruits were easier to collect, I could see myself making this more often, but who has the time?

The leaves and stems of Galium aparine are also edible, and the plant is said to be a particular favorite of geese and chickens, bringing about yet another common name, goosegrass. In the book Weeds, Gareth Richards discusses the plant’s edibility: “It’s edible for humans but not that pleasant to eat; most culinary and medicinal uses center around infusing the plant in liquids.” Cooking with the leaves or turning them into some sort of spring tonic is something I’ll consider for a future post about eating cleavers.

More Eating Weeds Posts on Awkward Botany

Apriums and Plumcots and Pluots, Oh My!

I was once a teenage paper carrier in small town Idaho. One of my stops was an apartment complex, and for much of the year, this was an uneventful stop. But for a few weeks in the summer, the purple-leaved plum trees out front had ripe fruit on them, and each time I was there, I would stop and take a few. In general, I don’t get that excited about fruit, but I enjoyed eating these plums. This variety of plum is typically planted for its looks rather than its fruit, and it may even be the tree that recently received a pitifully low score on an episode of Completely Arbortrary. Ornamental plum or not – and low cone score or not – I thought the fruit was good.

Many of the things we eat are a result of crosses between two related species, and plums are a great example of this. Species are species because they are reproductively isolated. A species does not typically mate with a member of another species and create viable offspring, except this happens all the time both naturally and artificially. In many cases, the offspring isn’t actually viable, but there is offspring nonetheless, and in the case of plants, that offspring can then reproduce asexually – by leaf, stem, or root cuttings or by some other means – and the resulting hybrid can exist indefinitely. One species mating with another species (specifically two species that are members of the same genus) is called interspecific hybridization, and there is a good chance that you’ve eaten something recently that is a result of this.

One of the most widely grown species of plum, Prunus domestica (commonly known as European plum), is a result of interspecific hybridization that occurred many centuries ago. A paper published in Horticulture Research (2019) confirmed that P. domestica originated as a cross between Prunus cerasifera and Prunus spinosa, the latter of which may have also been a result of interspecific hybridization. There are over 400 species in the genus Prunus that are distributed across temperate regions in the northern hemisphere. Within this genus is the subgenus Prunus (or Prunophora), a group that includes dozens of familiar species such as the plums, apricots, peaches, and almonds. Due to their close relationship, both natural and artificial hybridization among members of this subgenus is common, which explains the origin of Prunus domestica, as well as the majority of the plums we grow today.

Current commercial production of plums in North America is largely thanks to work done by Luther Burbank in the late 19th to early 20th centuries. Burbank was obsessed with plant breeding and released hundreds of new varieties of all kinds of different plants during his decades long career. He seemed particularly interested in plums, developing 113 different cultivars, which account for more than half of all his fruit releases. Probably his most well known plum variety is ‘Santa Rosa,’ which thanks to modern day genetics has been determined to be a cross between at least four different species of plum.

apriums

Early colonizers to the American continent were mainly growing varieties of the European plum they had brought over from Europe. North America is also home to several species of plums, which are used by indigenous populations. Shortly before Burbank began working with plums on his farm in California in 1881, Asian plum species were imported to the U.S., and breeders began using them in crosses with both European and North American plum species. Burbank became particularly engulfed in these efforts. In an article published in HortScience (2015), David Karp writes, “In the history of horticulture it is rare to find an individual who almost single-handedly created a new commercial industry based on a novel fruit type as Luther Burbank did for Asian-type plums in the United States.” Most Asian-type plums sold in stores today are hybrids of several different plum species due to the numerous complex crosses that Burbank made.

Burbank is also said to be the first to cross plums and apricots, creating the first of many cultivars of the plumcot. Plum and apricot crosses didn’t really catch on for a few more decades, and when they did, it was thanks to the work of Floyd Zaiger of Zaiger Genetics who developed and released numerous varieties. Apriums and Pluots are Zaiger Genetics trademarks, along with a few other unlikely crosses with plums and their related counterparts.

plumcots

A plumcot is the simplest cross. It is said to be 50% Asian plum (Prunus salicina) and 50% apricot (Prunus armeniaca). However, due to all the breeding of Asian plums carried out by Burbank and others, the Asian plum involved in the cross is typically a hybrid with other plum species, as discussed in a recent paper published in Plants (2022). An aprium is the result of a cross between a plumcot and an apricot, making it 75% apricot and 25% plum, while a pluot is a cross between a plumcot and a plum, making it 75% plum and 25% apricot. There is typically much more that goes into making these crosses, but that’s the general idea. If you’re lucky, you can find all three of these intraspecific crosses in a produce section near you, but it may not be clear what cultivar you’re purchasing. Myriad cultivars have been released of each of these hybrids – each one varying in color, size, flavor, disease resistance, etc. – and unfortunately most grocery stores don’t include cultivar names on their products, so it’s difficult to know what you’re getting.

At Awkward Botany Headquarters, there is a plum tree growing in our front yard. We didn’t plant it, so at this point I have no idea what species or cultivar it is. The plums are delicious though, and the leaves aren’t purple like the plums I used to eat on my paper route. Considering all of the intraspecific crossing that has gone on with plums, it’s quite likely that it is a combination of different species, which isn’t going to make it easy to figure out. But I’ll do my best.


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Randomly Selected Botanical Terms: Glochids

The spines of a cactus are an obvious threat. They are generally sharp, smooth, and stiff; as soon as you are stabbed by one, it is immediately clear that you’ve gotten too close. Sitting at the base of the spines – or in place of spines – on many species of cacti is a less obvious, but significantly more heinous threat. Unless you’re looking closely, this hazard is practically invisible, and the pain and irritation that can come as a result of close contact has the potential to last significantly longer than the sharp poke of a spine. This nefarious plant part is called a glochid, and if you’ve ever made contact with one (or more likely several dozen of them), it’s not something you will soon forget.

Opuntia polyacantha x utahensis

The spine of a cactus is actually a leaf. The area from which a spine emerges from the fleshy, photosynthetic stem of a cactus is called an areole, which is equivalent to a node or bud on a more typical stem or branch from which leaves emerge. In place of typical looking leaves, a cactus produces spines and glochids. Like spines, glochids are also modified leaves, although they appear more like soft, little tufts of hair. However, this unassuming little tuft is not to be trifled with.

Close inspection of a glochid (with the help of a microscope) reveals why you don’t want them anywhere near your skin. While the surface of a cactus spine is often smooth and free of barbs, glochids are covered in backwards-facing barbs. The miniscule size of glochids combined with their pliable nature and retrose barbs, make it easy for them to work their way into your skin and stay there. Unlike spines, glochids easily detach from a cactus stem. Barely brushing up against a glochid-bearing cactus can result in getting stuck with several of them.

Opuntia basilaris var. heilii

Because glochids can be so fine and difficult to see, you may not even be aware they are there. You probably won’t even feel them at first. Removing them is a challenge thanks to their barbs, and since you may not be able to remove them all, the glochids that remain in your skin can continue to cause irritation for days, weeks, or even months after contact. For this reason, cactuses are generally best seen and not touched, or at the very least, handled with extreme care.

Apart from being a good form of defense, the glochids of some cactus species can serve an additional function. Most cactus species occur in arid or semi-arid climates, where access to water can be quite limited. In order to increase their chances of getting the water they need, some desert plants are able to collect water from the air. A few species of cactus do this, and glochids are a critical component in making this happen.

Cylindropuntia whipplei

A study published in the Journal of King Saud University – Science (2020) examined the dew harvesting ability of Opuntia stricta, commonly known as erect prickly pear. As described above, the spines of O. stricta are smooth, while the glochids are covered in retrose barbs. Both structures are waterproof due to hardened cell walls and cuticles. However, due in part to the conical shapes of both the glochids and their barbs, water droplets from the air are able to collect on the tips of the glochids. From there, the researchers observed the droplets in their travel towards the base of the glochids. As they moved downward, small droplets combined to form larger droplets.

At the base of the glochids are a series of trichomes, which are small hair-like outgrowths of the epidermis. The trichomes do not repel water, but rather are able to absorb the droplets as they reach the base of the glochids. For a plant species that receives very little water from the soil, being able to harvest dew from the air is critical for its survival, and this is thanks in part to those otherwise obnoxious glochids.

See Also: Prickles

Weeds of Boise: Hellstrip on Jefferson Street

Growing plants in urban areas comes with a variety of challenges. Soil conditions aren’t always ideal; shade thrown by buildings and other structures can be difficult to work around; paved surfaces lead to compaction and, among other things, can increase temperatures in the immediate area; and in locations where water is limited, keeping plants hydrated is a constant concern. One location that tends to be especially difficult for gardeners is the hellstrip – the section of ground between a roadway and a sidewalk. Much can be said about gardening in hellstrips, so much that there is even a book about it called Hellstrip Gardening by Evelyn Hadden, which I spent several posts reviewing a few years back.

The difficulty of maintaining a hellstrip (and perhaps questions about who is responsible for maintaining it in the first place) can result in it being a piece of property frequently subject to neglect. In urban areas, neglected land is the perfect place for weeds to take up residence. The conditions in a hellstrip being what they are – hot, dry, frequently trampled, and often polluted – also gives weeds a chance to show what they can do. It’s a wonder that any plant can survive in such conditions, but the wild flora of our cities consists of some pretty tough plants, and a hellstrip is an excellent location to familiarize yourself with some of these plants.

On a walk with Kōura, I came across a weedy hellstrip on Jefferson Street in downtown Boise. Many of the classic hellstrip challenges are present there – it’s surrounded by paved surfaces, there is lots of foot traffic in the area, parking is permitted on the roadside, urban infrastructure (street signs, parking meters, stoplights) is present within the strip. It’s clear that at one point the area was being maintained as irrigation is installed and there are remnants of turfgrass. Three honey locusts were also planted in the strip, one of which has clearly died. Now that maintenance seems to have ceased, weeds have become the dominant flora in this hellstrip. 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.

shepherd’s purse (Capsella bursa-pastoris) and prickly lettuce (Lactuca serriola)
dandelion (Taraxacum officinale)
salsify (Tragopogon dubius)
seed head of salsify
knotweed (Poylgonum sp.)
prickly lettuce (Lactuca serriola)
mallow (Malva neglecta)
orchard grass (Dactylis glomerata)
  • Bromus tectorum (cheatgrass)
  • Capsella bursa-pastoris (shepherd’s purse)
  • Dactylis glomerata (orchard grass)
  • Epilobium brachycarpum (tall willowherb)
  • Lactuca serriola (prickly lettuce)
  • Malva neglecta (dwarf mallow)
  • Polygonum sp. (knotweed)
  • Salsola sp. (Russian thistle)
  • Taraxacum officinale (dandelion)
  • Tragopogon dubius (salsify)
  • Trifolium repens (white clover)
  • Vulpia myuros (rattail fescue)

Are there unkept hellstrips in your neighborhood? If so, what weeds have you seen taking up residence there?

Flowers Strips Bring All the Pollinators to the Yard

The longer I garden the more I gravitate towards creating habitats for creatures that rely on plants for survival. I’ve always been more interested in functional gardens rather than gardens that are simply “plants as furniture” (as Sierra likes to say) – a manicured, weed-free lawn, a few shrubs shaped into gumdrops, sterile flowers for color – and that interest has grown into a way of life. A garden should be more than just something nice to look at, and for those of us who’ve embraced the “messy ecosystems” approach, what’s considered “nice to look at” has shifted dramatically.

Thankfully, I’m not alone in this thinking. Gardens focused on pollinators, birds, habitats, native plants, etc. seem to be gaining in popularity. The question is, is it making a difference? At least one study, referred to below, seems to suggest that it is. And as more gardens like these are planted and more studies like this are done, perhaps we will get a clearer picture of their impact.

In 2017, eight 1000 square meter flower strips were planted in Munich, Germany. The sites had previously been lawn or “roadside greenery,” according to the report published in the Journal of Hymenoptera Research (2020). An additional flower strip, planted in 2015, was included in the study. Over the next year, an inventory of the number of bee species found in these nine flower strips was taken and compared both to the number of bee species that had been recorded in Munich since 1795 (324 species) and the number of bee species recorded in the 20 years prior to the planting of the flower strips (232 species).

In just a year’s time, these newly planted flower strips quickly attracted a surprising number of bees. The researchers identified 68 different species (which is 21% and 29% of the two categories of previously recorded species). As they had expected, most of the bees they identified were common, non-threatened, generalist species; however, they were surprised to also find several species that specialize on pollen from specific groups of plants. Future studies are needed to determine whether or not such flower strips help increase the populations of pollinators in the city, but it seems clear that they are a simple way to increase the amount of food for pollinators, if nothing else.

But perhaps these results shouldn’t be that surprising. Urban areas are not necessarily the biodiversity wastelands that the term “concrete jungle” seems to imply. Though fragmented and not always ideal, plenty of wildlife habitat can be found within a city. In his book, Pollinators and Pollination, Jeff Ollerton lists a number of studies that have been carried out in cities across the world documenting an impressive number of pollinating insects living within their borders [see this report in Conservation Biology (2017), for example]. As Ollerton writes, these studies “show that urbanization does not mean the total loss of pollinator diversity, and may in fact enhance it.” After all, “many of us city dwellers see every day, nature finds a home, a habitat, a place to thrive, wherever it will.”

In a chapter entitled, “The Significance of Gardens,” Ollerton continues to explore the ways in which cities can host a wide variety of flower visiting insects and birds. “Planted patches” don’t necessarily need to be managed as pollinator gardens in order to provide resources for these creatures, nor do all of the plants need to be native to the region to be effective. Rather, diversity in flower structure and timing seems to be key; “floral diversity always correlates with pollinator diversity regardless of the origin of the plants,” Ollerton writes in reference to pollination studies performed in British cities. The more “planted patches,” the better, as “a large and continuous floral display in gardens is the only way to maximize pollinator abundance and diversity.” Add to that, “if you allow some areas to become unmanaged, provide other suitable nesting sites or areas for food plants, and other resources that they need, a thriving oasis for pollinators can be created in any plot.”

ground nesting bee emerging from burrow

Bees and other pollinating insects are finding ways to live within our cities. There is no need to go to the lengths that I like to go in order to help them out. Simply adding a few more flowering plants to your yard, balcony, or patio can do the trick. Eliminating or limiting the use of pesticides and creating spaces for nesting sites are among other things you can do. Learning about specific pollinators and their needs doesn’t hurt either. The continued existence of these creatures is critical to life on earth, and this is one important issue where even simple actions can make a real difference.


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Awkward Botany on Outdoor Idaho (plus Send Us Your Questions)

I spend a lot time on this blog putting weeds in the spotlight, celebrating them for their successes and the unique and interesting plants they are. It’s rare that I get to share these sentiments outside of this particular venue, but I was given such an opportunity recently when asked to talk about weeds for an episode of Outdoor Idaho, a long running show on Idaho Public Television that covers Idaho’s natural history. The theme of this particular episode is wildflowers, so I was intrigued by the idea of coming on to discuss urban weeds. For many, the term “wildflowers” may invoke native plants blooming in natural areas in places far removed from the hustle and bustle of the city. But a wildflower doesn’t have to be a native plant, nor does it have to be growing in the wild. Any plant occurring naturally on its own without the assistance of humans can be a wildflower, and that includes our wild urban flora. I appreciated the chance to share this particular thought with the viewers of Outdoor Idaho.

photo credit: Jay Krajic

Along with me waxing on about weeds, the Wildflowers episode features a host of other Idahoans sharing their thoughts, expertise, and experiences with wildflowers. The episode is brief – coming in at under 30 minutes – but the producers packed in a ton of great wildflower content, and overall I found it to be an excellent representation of the flora of Idaho and a convincing argument for why we should appreciate and elevate these plants. The flora of any region is special and important in its own right, and Idaho’s flora is no different, including its weeds.

Check out Outdoor Idaho’s Wildfowers episode here.

In other news…

If you want to see more of me on the screen (and I’m not sure why you would), Sierra (a.k.a. Idaho Plant Doctor) and I are doing monthly Q&A videos in which we answer your questions about plants, gardening, pests and diseases, insects, or any other topic you might be curious about. You can tune in to those discussions on Sierra’s instagram. If you have questions of your own that you would like us to address, please leave them in the comments section below, or send them to me via the contact page or my instagram.

Weeds of Boise: Vacant Lot on West Kootenai Street

Every urban area is bound to have its share of vacant lots. These are sites that for whatever reason have been left undeveloped or were at one point developed but whose structures have since been removed. The maintenance on these lots can vary depending on who has ownership of them. Some are regularly mowed and/or treated with herbicide, while others go untouched for long periods of time. Even when there is some weed management occurring, vacant lots are locations where the urban wild flora dominates. Typically no one is coming in and removing weeds in an effort to cultivate something else, and so weeds run the show.

As with any piece of land populated by a diverse suite of wild plants, vacant lots are dynamic ecosystems, which you can read all about in the book Natural History of Vacant Lots by Matthew Vessel and Herbert Wong. The impact of humans can be seen in pretty much any ecosystem, but there are few places where that impact is more apparent than in a vacant lot. In lots located in bustling urban centers, human activity is constant. As Vessel and Wong write, “numerous ecosystem interactions are affected when humans intervene by spraying herbicides or insecticides, by trampling, by physically altering the area, or by depositing garbage and waste products.” These activities “can abruptly alter the availability and types of small habitats; this will in turn affect animal as well as plant diversity and population dynamics.” The dynamic nature of these sites is a reason why vacant lots are excellent places to familiarize yourself with the wild urban flora.

Kōura relaxing in a vacant lot

On our morning walks, Kōura and I have been visiting a small vacant lot on West Kootenai Street. We have watched as early spring weeds have come and gone, summer weeds have sprouted and taken off, perennial weeds have woken up for the year, and grass (much of which appears to have been intentionally planted) has grown tall and then been mowed with some regularity. Someone besides us is looking after this vacant lot, and it’s interesting to see how the plant community is responding. As Vessel and Wong note, “attempts to control weedy plants by mowing, cultivating, or spraying often initiate the beginning of a new cycle of growth.” For plants that are adapted to regular disturbance, measly attempts by humans to keep them in check are only minor setbacks in their path to ultimate dominance.

What follows are a few photos of some of the plants we’ve seen at the vacant lot on Kootenai Street, as well as an inventory of what can be found there. This list is not exhaustive and, as with other Weeds of Boise posts, will continue to be updated as I identify more species at this location.

dandelion (Taraxacum officinale)
grape hyacinth (Muscari armeniacum)
henbit (Lamium amplexicaule)
wild barley (Hordeum murinum) backed by cheatgrass (Bromus tectorum)
narrowleaf plantain (Plantago lanceolata) and broadleaf plantain (Plantago major)
perrennial sweet pea (Lathyrus latifolius) surrounded by redstem filaree (Erodium cicutarium)
whitetop (Lepidium sp.)
white clover (Trifolium repens)
  • Bromus tectorum (cheatgrass)
  • Capsella bursa-pastoris (shepherd’s purse)
  • Ceratocephala testiculata (bur buttercup)
  • Descurainia sophia (flixweed)
  • Draba verna (spring draba)
  • Erodium cicutarium (redstem filaree)
  • Geum urbanum (wood avens)
  • Holosteum umbellatum (jagged chickweed)
  • Hordeum murinum (wild barley)
  • Lactuca serriola (prickly lettuce)
  • Lamium amplexicaule (henbit)
  • Lathyrus latifolius (perennial sweet pea)
  • Lepidium sp. (whitetop)
  • Malva neglecta (dwarf mallow)
  • Muscari armeniacum (grape hyacinth)
  • Plantago lanceolata (narrowleaf plantain)
  • Plantago major (broadleaf plantain)
  • Poa bulbosa (bulbous bluegrass)
  • Poa pratensis (Kentucky bluegrass)
  • Rumex crispus (curly dock)
  • Taraxacum officinale (dandelion)
  • Tragopogon dubius (salsify)
  • Trifolium repens (white clover)
  • Veronica sp. (speedwell)

If you live in an urban area, chances are good there is a vacant lot near you. What have you found growing in your neighborhood vacant lot? Feel free to share in the comment section below.

In Praise of Vagabond Plants – A Book Review

A weed is a highly successful plant that shares a close relationship with humans. In many instances, weeds are seen as nuisance plants, interfering with the goals and intentions we have for a piece of land. In natural areas, they are blamed for, among other things, threatening the existence of the native flora, despite the fact that human activity and disturbance brought them there in the first place and continued human disturbance helps keep them there. In some instances, such as a vacant lot in an urban area, they pose no threat and their existence causes little if any harm, yet they are disparaged for being unsightly, hazardous, and out of place. Nevermind the fact that they are offering a number of ecosystem services free of charge.

For all these reasons and more, weeds get called some pretty nasty things and are the recipient of an unduly amount of ire. The extent that some of us will go to vilify a plant is a bit disturbing to me, so it’s always refreshing to come across a more reasonable approach to weeds. That tempered take is what I found in Gareth Richards’ book, Weeds: The Beauty and Uses of 50 Vagabond Plants, a production of the Royal Horticultural Society and whose vast archives were used to beautifully illustrate the book.

There seems to be a growing trend in the U.K. and other parts of Europe to be more accepting of weeds, to see them as part of our urban, suburban, and exurban flora, and to focus on the value they may bring rather than constantly reviling them as interlopers and thus trying to blast them out of existence with chemical warfare. (See also Wild About Weeds by Jack Wallington). I hope this is true, and I hope the trend continues and catches on in other parts of the world. As Richards writes, “Often the only crime a plant has committed is growing too well.” Thankfully, books like this help bring awareness to these highly fecund and robust plants and their many redeeming qualities.

Richards’ book starts out with a brief introduction and then proceeds with short profiles of 50+ different plant species that are commonly considered weeds. The focus of the book is on weeds found in the U.K.; however, weeds being what they are, at least a few (if not most) of the plants covered are bound to be growing near you regardless of where you live in the world. While there is some discussion of the invasive nature of a few of the plants profiled and the illegality of growing or transporting them – see Japanese knotweed, Himalayan balsam, and pontic rhododendron for example – the focus is not on management nor control. Instead, the discussion revolves around interesting aspects of the plants that makes them worth getting to know rather than something to simply eliminate.

As is often the case when discussing specific plants, medicinal uses and edibility feature heavily in Richards’ plant profiles. It’s interesting to learn about the many ways that humans have thought about and used plants historically, and some of the ways they were historically used are certainly still relevant today; however, many medicinal claims don’t stand the test of time nor do they have empirical evidence to back them up. For this reason, I generally take medicinal uses of plants with a grain of a salt and a healthy dose of skepticism. Edibility, on the other hand, has always been interesting to me, and just when I thought I had heard all the ways that dandelions can be eaten, Richards introduces me to another: “You can even harvest the flower buds for pickling; they make a useful homegrown caper substitute.”

What follows are a few excerpts from the book with accompanying photos of the plants in question.

Ground elder (Aegopodium podagraria) was originally introduced to gardens for its medicinal and edible qualities, but its aggressive behavior can be frustrating. Richards notes, “A useful plant for brave gardeners!”
The rhizomatous nature of yarrow (Achillea millefolium) makes it an excellent addition or alternative to turf grass, and thanks to its drought-tolerance, Richards asserts, “certainly lawns containing yarrow stay greener for longer in dry spells.
Speaking of lawns, “Creeping buttercup (Ranunculus repens) in your lawn is generally a sign that it’s too wet for short grass to thrive.” Richards recommends letting it become a meadow instead. “Sometimes the most rewarding way of gardening is to let nature do it for you.”
Regarding teasel (Dipsacus spp.), Richards writes: “It’s not only bees that adore them; when the seeds ripen they’re loved by birds, especially goldfinches. Try planting some in your garden as a homegrown alternative food source to replace shop-bought nyjer seed.” (photo credit: Sierra Laverty)
“Cats and dogs seek out couch grass (Elymus repens) when they want to chew on something – either for its minerals or to help them vomit to clear their stomachs, often of furballs.” Kōura can frequently be found chewing on it.
“Like many weeds, herb bennet (Geum urbanum) has some clever adaptations. Its nondescript leaves blend seamlessly with other plants, never drawing attention to themselves. And those [clove-scented] roots are really tough, making plants physically difficult to pull up by hand. … The seeds have small hooks and readily attach themselves to fur and clothing to hitch a free ride to pastures new.”

Regardless of how you feel about weeds, if you’re interested in plants at all, this book is worth getting your hands on and these plants are worth getting to know. They may not be the plants you prefer to see growing on your property, but they have interesting stories to tell and, in many cases, may not be as big of a problem as you originally thought. In discussing Spanish bluebells (Hyacinthoides hispanica) and its weedy relatives, Richards hits on a point that for me is one of the main takeaways of this book: “In an age where gardens are becoming wilder and the countryside ever more fragmented, and nature is on the march due to climate change, perhaps we should just learn to treasure the wild plants that thrive in the the new conditions we have made – wherever they originally came from.”

More Weeds Themed Book and Zine Reviews:

Randomly Selected Botanical Terms: Prickles

Let’s start by getting something out of the way: roses have prickles, not thorns. However, just like peanuts aren’t actually nuts and tomatoes are actually fruits, our colloquial terms for things don’t always match up with botanical terminology. This doesn’t mean that we should be pedants about things and go spoiling a friendly dinner party with our “well, actually…” corrections. If you hear someone saying (or singing) something about every rose having its thorn, it’s okay to just let it go.

So why don’t roses have thorns? And what even is a prickle anyway?

Plants have a way of modifying various body parts to form a variety of features that look like something totally new and different. When the development of these features are observed at a cellular level, we find that what once may have grown into something familiar, like a stem, is now something less familiar, like a thorn. A thorn, then, is a modified stem. Stem tissue was used by the plant to form a hardened spike. Thorns help protect a plant from being eaten, so going through the trouble of producing this feature is a benefit to the plant.

thorns of hawthorn (Crataegus sp.)

Spines and prickles are similar features to thorns and serve a similar purpose, but they have different origins. Spines are modified leaf or stipule tissue (the spines on a cactus are actually modified leaves). Prickles are outgrowths of the epidermis or bark. In plants, epidermis is a single, outer layer of cells that covers all of the organs (i.e. leaves, roots, flowers, stems). Outgrowths on this layer are common and often appear as little hairs. The technical term for these hairs or hair-like structures is trichomes.

the stems of staghorn sumac (Rhus typhina) are covered in dense trichomes

Prickles are much like trichomes, but there are usually less of them and they are hardened and pointy. They can be sharp like a thorn or spine and so are often confused for them. (Spines are also confused for thorns, as is the case with Euphorbia milii, whose common name is crown of thorns but whose “thorns” are actually spines.) As stated above, their cellular origin is different, and unlike thorns and spines, prickles don’t have vascular tissue, which is the internal tissue that transports water and nutrients throughout all parts of the plant. In general, prickles can be easily broken off, as they are often weakly attached to the epidermis.

Prickles are most commonly observed on roses and come in a variety of shapes, sizes, and colors.

Prickles on roses are commonly called thorns, and that’s okay. Thorn is perhaps a more poetic word and easier to relate to. But really, I’m torn and forlorn that they aren’t thorns. It puts me in a pickle trying to rhyme words with prickle.


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