Weeds of Boise: Neglected Parking Lot Islands at Post Office on 13th Street

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)
  • Sonchus oleraceus (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.

Book Review: Wild Wasatch Front

If it isn’t clear by now from my Weeds of Boise series and countless other posts, I happen to be interested in the flora and fauna of urban areas. Urban ecology is a fascinating field of study, and I’m not sure that it gets the attention it deserves. Nature is not some far away place, and you shouldn’t have to leave city limits to go in search of it. Remarkably, nature exists right outside your front door, even if you live in the middle of a massive city. It may be a different sort of nature than the one you might find in a national forest or a state park, and it may be composed of species introduced from all corners of the world, but it is still a collection of living organisms interacting with each other and the surrounding environment in unique and important ways. The question is, can you grow to appreciate nearby nature and recognize that the ecological interactions that exist within the context of a city are just as valid as those you’ll find outside of our built environments?

Luckily, there are resources that can help you with that, including a recent book compiled by Lisa Thompson and others at the Natural History Museum of Utah (NHMU). It’s called Wild Wasatch Front, and it’s of particular interest to me because it covers a region that’s relatively close by, and our two locations share a number of similarities. Plus, I played a small role in reviewing some of the plants (specifically the weeds) that ended up in the book (Sierra would insist that I mention this, so there you go). Similar books exist for other regions across North America and elsewhere, so I encourage you to seek out a book that applies to your hometown.

The Wasatch Front is a metropolitan region in north-central Utah that spans the western side of the Wasatch Mountains and includes a long string of cities and towns extending for many miles in all directions. Included in that list of cities is Salt Lake City, the state’s capitol and largest city in the state. The idea for a book about urban nature in the Wasatch Front was inspired by an exhibit at NHMU called “Nature All Around Us.” The exhibit and resulting book offer a new perspective for those insisting that “nature and cities cannot coexist” or that the nature found in cities is influenced by humans and therefore shouldn’t be considered “real.” Hundreds of organisms making a life for themselves within the boundaries of our cities might argue otherwise.

Wild Wasatch Front is divided into three main sections, with each section being worth the price of the book on its own. First there are a series of essays about urban nature and ecology. Names you might recognize, including Emma Marris and Riley Black, contributed to the book, as well as several other people that live and work in the western U.S. and have an interest in nature and environmental issues, especially as they relate to cities. Novel ecosystems is a reoccurring theme, not just in the essays but throughout the book. In her essay, Sarah Jack Hinners writes, “urban nature is a mixture of the intentional and the unintentional,” adding that “for every tree or rosebush or lawn that we plant and carefully nurture, there are multitudes of other plants and animals that grow and thrive uninvited and unnurtured by us.”

The largest section in the book is a field guide, profiling 127 plus species that call the Wasatch Front home, some native and some transplants. This section is divided into subsections that include birds, invertebrates, fungi and lichen, mammals, reptiles and amphibians, street trees, and wild plants. The entry for each species includes a brief description, a few interesting facts, and details on how and where to find them, accompanied by images. With the variety of creatures covered, you are sure to find something that interests you and a reason to go out looking for your favorites. You may even learn something new about a species you’ve been seeing for years, such as house finches. It turns out that the colorful patches on a male house finch are the result of the plants they eat. These patches can be red, orange, or yellow. The redder the better though, because female house finches seek out mates with this coloration.

Naturally, my focus was mainly aimed at the plants covered in this section. I appreciated the mixture of native and introduced plants, even the inclusion of plants considered to be invasive. Instead of vilifying these species, there is an attempt to understand them and find value in them, even in spite of the concerns and negative opinions held about them. Box elder (Acer negundo) is an example of a plant that has both native and introduced populations. Once widely planted in yards and on farms, this tree has “fallen out of favor.” Its weak wood (a result of growing so quickly), can result in a messy, unattractive tree, making it a poor choice for a street tree. However, it propagates itself readily and shows up in vacant lots and other urban locations that receive minimal management and human attention. In the Wasatch Front, you can find box elders that are native, naturalized, and cultivated, an unlikely scenario unique to urban areas.

massive box elder (Acer negundo) in Boise, Idaho

The third and final section of the book is a guide to 21 different hikes and field trips in and around the Wasatch Front. Each field trip features a hand-drawn map and some basic notes about the hike. Details about what can be seen along the way are included in the descriptions, which are sure to entice you into visiting. Whether or not you think you’ll ever make it out to any of these spots, this section is still worth reading if only for the ongoing discussions about urban ecology. For example, in the entry for Gib’s Loop, abrupt changes in land ownership and land use (a common experience when hiking in urban areas) is addressed: “Human impacts in the foothills…don’t end at backyard fences, and many animals use resources in both habitats. It’s more interesting to think of cities and the surrounding foothills as part of an interconnected system rather than separate and distinct.”

The field trip section is also used as a teaching opportunity to describe more of the species you’ll find in the Wasatch Front. In the entry for Creekside Park, learn how to identify creeping mahonia (Berberis repens), with its low growing habit and matte leaves, and compare it to Oregon grape (B. aquifolium), with its more upright habit and shinier leaves.

Berberis aquifolium (on the left) compared to Berberis repens (on the right)

Last year, in anticipation of Wild Wasatch Front, I came across another book with a similar focus. This book was put out by a group called The Urban Field Naturalist Project, headquartered in Australia. Their book, A Guide to the Creatures in Your Neighbourhood, encourages its readers to become urban naturalists and offers resources to help them get started. Just like Wild Wasatch Front, the bulk of the book is a field guide to species found in and around urban areas (in Australia, of course). In place of a guide to hikes and field trips, there are instructions on how to start nature journaling, which is a key component of becoming an urban field naturalist. Getting outside and learning to recognize nearby nature is step one, documenting what you see and sharing those observations with others is step two. Taken together, these two books will help you gain a better appreciation for urban nature and will hopefully inspire you to work to conserve what is there and make room for more.

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