Two years ago I shared my first collection of urban botanical art photos. Since that time I have collected several more. I had hoped to get lots of photos during my trips out of town, and while I did manage to get a few, it turns out that my hometown of Boise, Idaho has a sizable (and growing) selection of plant-related public art. Thus, several of these are local finds.
This post originally appeared on Idaho Botanical Garden’s blog. With the first annual Boise Goathead Fest fast approaching, the purpose of this post is to help people in the Treasure Valley identify goatheads so that they can collect them for drink tokens to use at the event. I’m reposting it here in hopes that people around the globe who are tormented by goatheads might benefit from it. All photos in this post were taken by Anna Lindquist.
If you have spent much time on a bicycle in Boise, chances are you have been the victim of a goathead-induced flat tire. You probably even got a good look at the spiky nutlet as you went to remove it from your tire. But where did the culprit come from? No doubt, it came from a plant. But which one?
This is particularly useful to know right now because the first annual Boise Goathead Fest is coming up, and if you manage to fill a garbage bag full of these noxious weeds before the end of July, you will earn yourself a drink token. Fortunately, this plant is fairly easy to identify; however, there are a few look-a-likes, so it is important to familiarize yourself with the plant in question so you can be sure you are pulling the right one.
Puncture vine, also known as goathead or Tribulus terrestris, is a warm season annual that is native to the Mediterranean region of southern Europe. It was introduced to North America unintentionally by early European settlers when the plant’s blasted burs snuck their way across the ocean in sheep wool. Since then, puncture vine has spread across the continent prolifically thanks to the hitchhiking prowess of its seeds.
Puncture vine has a prostrate habit, meaning that its branches lie flat on the ground, spreading outward from a central location. It grows upward only when it is being shaded or crowded out. Its leaves are divided into several tiny leaflets, and its flowers are small and bright yellow with five petals. It is an otherwise pretty plant were it not for the threatening, jagged fruits that follow the flowers. As these fruits dry, they dislodge from the plant, split into five pieces, and lay in wait to puncture your tire, work their way into the bottom of your shoe or the foot of an animal, or latch onto some errant fur.
Depending on the conditions, puncture vine either remains fairly small or spreads as much as six feet wide. Fruits start forming shortly after flowering, and seeds ripen soon after that, so if the plant isn’t removed quickly – nutlets and all – future populations are guaranteed. Luckily the plants are fairly easy to remove. Unless the ground is particularly compact, they pull up easily, and if they break off at the root, they generally don’t sprout back.
Virtually any plant that has a prostrate growth habit and is actively growing in the summer could, at first glance, be mistaken for puncture vine. Closer inspection will help confirm the plant’s true identity. Two plants that might confuse you are purslane and spotted spurge. Both of these species can be found growing in full sun in disturbed or neglected sites in close company with puncture vine.
Purslane has tiny, yellow, five-petaled flowers similar to puncture vine; however, its leaves are glossy and succulent-like and its stems and leaves often have a red to purple hue to them. Purslane seeds are miniscule, and while the plant can be a nuisance in a garden bed, it poses no threat to bicycles or wildlife.
Spotted spurge, also known as prostrate spurge, can be quickly distinguished by the milky sap that oozes from its broken stems. Its leaves are generally reddish purple on the undersides with a purple spot on top. Its flowers are minute and its seeds even smaller. Because its sap contains latex and other chemicals, it can irritate the skin and poison creatures that dare eat it.
Both of these plants are introduced, weedy species, so even if they won’t count towards your drink token, it still doesn’t hurt to pull them. Puncture vine, however, is included on Idaho’s noxious weed list, which means it is particularly problematic. So take this opportunity to pull as many as you can, and hopefully we can put a sizeable dent in the population of a plant that has tormented Boise bicyclists for far too long.
See Also: Plant vs. Bike
Demonstration gardens are one of the best places to learn about drought tolerant plants that are appropriate for your region. Such gardens not only help you decide which species you should plant, but also show you what the plants look like at maturity, what they are doing at any given time of year, and how to organize them (or how not to organize them, depending on the quality of the garden) in an aesthetically pleasing way. A couple of years ago, I explored the Water Efficient Garden at the Idaho State Capitol Building. This year I visited the Water Conservation Landscape at Idaho Botanical Garden in Boise, Idaho.
The Water Conservation Landscape is planted on a large L-shaped berm on the edge of Idaho Botanical Garden’s property. It is the first thing that visitors to the garden see, before they reach the parking area and the front gate. It is nearly a decade old, so the majority of the plants are well established and in their prime. Because the garden is so visible, year-round interest is important. This imperative has been achieved thanks to thoughtful plant selection and design.
This demonstration garden came about thanks to a partnership between Idaho Botanical Garden and several other organizations, including the water company, sprinkler supply companies, and a landscape designer. An interpretive sign is installed at one end of the garden describing the benefits of using regionally appropriate plants to create beautiful drought tolerant landscapes. If you ever find yourself in the Boise area, this is a garden well worth your visit. In the meantime, here are a few photos as it appeared in 2017.
More Drought Tolerant Plant Posts:
Generally speaking, individual plants produce an enormous amount of seeds. This may seem like a huge waste of resources, but the reality is that while each seed has the potential to grow into an adult plant that will one day produce seeds of its own, relatively few may achieve this. Some seeds will be eaten before they get a chance to germinate. Others germinate and soon die from lack of water, disease, or herbivory. Those that make it past the seedling stage continue to face similar pressures. Reaching adulthood, then, is a remarkable achievement.
Antelope bitterbrush is a shrub that produces hundreds of seeds per individual. Each seed is about the size of an apple seed. Some seeds may be eaten right away. Others fall to the ground and are ignored. But a large number are collected by rodents and either stored in burrows (larder hoarding) or in shallow depressions in the soil (scatter hoarding). It is through caching that antelope bitterbrush seeds are best dispersed. When rodents fail to return to caches during the winter, the seeds are free to sprout in the spring. Some of the seedlings will dry out and others will be eaten, but a few will survive, making the effort to produce all those seeds worth it in the end.
Antelope bitterbrush (Purshia tridentata) is in the rose family and is often simply referred to as bitterbrush. It occurs in grasslands, shrub steppes, and dry woodlands throughout large sections of western North America. It is a deciduous shrub that generally reaches between three and nine feet tall but can grow up to twelve feet. It has wedge-shaped leaves that are green on top, grayish on bottom, and three-lobed. Flowers are yellow, strongly fragrant, and similar in appearance to others in the rose family. Flowering occurs mid-spring to early summer. Fruits are achenes – single seeds surrounded by papery or leathery coverings. The covering must rot away or be removed by animals before the seed can germinate.
Bitterbrush is an important species for wildlife. It is browsed by mule deer, pronghorn antelope, bighorn sheep, and other ungulates, including livestock. It provides cover for birds, rodents, reptiles, and ungulates. Its seeds are collected by harvester ants and rodents, its foliage is consumed by tent caterpillars and other insects, and its flowers are visited by a suite of pollinators. For all that it offers to the animal kingdom, it also relies on it for pollination and seed dispersal. The flowers of bitterbrush are self-incompatible, and if it wasn’t for ants and rodents, the heavy seeds – left to rely on wind and gravity – would have trouble getting any further than just a few feet from the parent plant.
In a study published in The American Naturalist (February 1993), Stephen Vander Wall reported that yellow pine chipmunks were the primary dispersal agents of bitterbrush seeds in his Sierra Nevada study area. The optimal depth for seedling establishment was between 10-30 millimeters. Seeds that are cached too near the surface risk being pushed out of the ground during freeze and thaw cycles where they can desiccate upon germination. Cached bitterbrush seeds benefit when there are several seeds per cache because, as Vander Wall notes, “clumps of seedlings are better able to push through the soil and can establish from greater depths than single seedlings.”
Another study by Vander Wall, published in Ecology (October 1994), reiterated the importance of seed caching by yellow pine chipmunks in the establishment of bitterbrush seedlings. Seed caches, which consisted of anywhere from two to over a hundred seeds, were located as far as 25 meters from the parent plant. Cached seeds are occasionally moved to another location, but Vander Wall found that even these secondary caches produce seedlings. Of course, not all of the seedlings that sprout grow to maturity. Vander Wall states, “attrition over the years gradually reduces the number of seedlings within clumps.” Yet, more than half of the mature shrubs he observed in his study consisted of two or more individuals, leading him to conclude that “they arose from rodent caches.”
A study published in the Journal of Range Management (January 1996) looked at the herbivory of bitterbrush seedlings by rodents. In the introduction the authors discuss how “rodents [may] not only benefit from antelope bitterbrush seed caches as a future seed source, but also benefit from the sprouting of their caches as they return to graze the cotyledons of germinating seeds.” In this study, Ord’s kangaroo rats, deer mice, and Great Basin pocket mice were all observed consuming bitterbrush seedlings, preferring them even when millet was offered as an alternative. The two species of mice also dug up seedlings, possibly searching for ungerminated seeds. Despite seed dispersal via caching, an overabundance of rodents can result in few bitterbrush seedlings reaching maturity.
Photos of antelope bitterbrush seedling clusters were taken at Idaho Botanical Garden, where numerous clusters are presently on display along the pathways of the native plant gardens and the adjoining natural areas.
2016 was another busy year at Awkward Botany headquarters. A major highlight was the response I received from the Help Wanted announcement that I posted early last year. Several people expressed interest in writing guest posts, while several others volunteered to help out in other ways (contributing images, illustrations, logos, etc.). The offer still stands, so please be in touch if you would like to contribute in any way.
Speaking of being in touch, the comments I’ve received and the connections I’ve made through social media and beyond really add to the experience of doing this blog. Not only does it make this more of a conversation, but it is greatly motivating to know that people find this to be a valuable and entertaining resource. Thank you to all who have reached out. And thanks to silent observers as well. Let’s stay in touch.
As I have done in the past, I am including a list of some of the posts from this past year, mainly those that are part of ongoing series. Many posts don’t fall within these categories, so all others can be found in the ‘Archives’ widget on the right side of the screen.
Famous Botanists in History:
Drought Tolerant Plants:
- Utah State University Botanical Center
- Bruneau Dunes State Park
- Coolwater Ridge Lookout
- Mud Springs Ridge and Cow Creek Saddle
Botany in Popular Culture:
Rare and Endangered Plants
- Jeremiah Sandler: Confidential Carnivore, Thoughts on Equisetum Phylogenesis, The Problem with ‘Yes’ Landscapes, and Cedar Confusion
- Mesquite Cervino: The Nippleworts of Camassia Natural Area
- Samuel Malley: Influence of a Passion
What Is a Plant, and Why Should I Care? part one, part two, part three, part four
Along with the great guest posts, I also received Awkward Botany logos from three incredible artists/graphic designers. I loved them all, and I am very thankful for the time and talent that was spent creating them. The logos are featured below. In order of appearance they were created by Franz Anthony, Mesquite Cervino, and Mara McCall. If you have an idea for an Awkward Botany logo, please let me know. I would love to see it.
And now a heads up…
In the coming months I plan to focus most of my posts on “weeds” and invasive species. These are topics that I have found increasingly intriguing, so I am hoping that writing a long series of posts about them will help satisfy my curiosity. This may or may not be your thing, but I hope you will stick around regardless. I plan to continue to include some guest posts, which will hopefully help break up the monotony. Also, I know I said this last year and it didn’t actually happen, but I will most likely be taking some breaks from my weekly publishing schedule in order to work on some other projects. Those projects and more will be revealed at some point in time, along with other ideas I have rolling around in my head. If the thought of me taking breaks from posting here bothers you, I invite you to join me on twitter and tumblr, where I will continue to post random things regularly.
Until then, I wish you all a splendid 2017. It should be an interesting one, so buckle up.
Despite being such a widely distributed and commonly occurring plant, Anaphalis margaritacea is, in many other ways, an uncommon species. Its native range spans North America from coast to coast, reaching up into Canada and down into parts of Mexico. It is found in nearly every state in the United States, and it even occurs throughout northeast Asia. Apart from that, it is cultivated in many other parts of the world and is “weedy” in Europe. Its cosmopolitan nature is due in part to its preference for sunny, dry, well-drained sites, making it a common inhabitant of open fields, roadsides, sandy dunes, rocky slopes, disturbed sites, and waste places.
Its common name, pearly everlasting, refers to its unique inflorescence. Clusters of small, rounded flower heads occur in a corymb. “Pearly” refers to the collection of white bracts, or involucre, that surround each flower head. Inside the bracts are groupings of yellow to brown disc florets. The florets are unisexual, which is unusual for plants in the aster family. Plants either produce all male flowers or all female flowers (although some female plants occasionally produce florets with male parts). Due to the persistent bracts, the inflorescences remain intact even after the plant has produced seed. This quality has made them a popular feature in floral arrangements and explains the other half of the common name, “everlasting.” In fact, even in full bloom, the inflorescences can have a dried look to them.
Pearly everlasting grows from 1 to 3 feet tall. Flowers are borne on top of straight stems that are adorned with narrow, alternately arranged, lance-shaped leaves. Stems and leaves are gray-green to white. Stems and undersides of leaves are thickly covered in very small hairs. Apart from contributing to its drought tolerance, this woolly covering deters insects and other animals from consuming its foliage. In The Book of Field and Roadside, John Eastman writes, “Insect foliage feeders are not numerous on this plant, owing to its protective downy ‘gloss.’ … The plant’s defensive coat seems to prevent spittlebug feeding on stem and underleaves. The tomentum also discourages ant climbers and nectar robbers.”
Not all insects are thwarted however, as Anaphalis is a host to the caterpillars of at least two species of painted lady butterflies (Vanessa virginiensis and V. cardui). Its flowers, which occur throughout the summer and into the fall. are visited by a spectrum of butterflies, moths, bees, and flies.
Because the plants produce either male or female flowers, cross-pollination between plants is necessary for seed development. However, plants also reproduce asexually via rhizomes. Extensive patches of pearly everlasting can be formed this way. Over time, sections of the clonal patch can become isolated from the mother plant, allowing the plant to expand its range even in times when pollinators are lacking.
The attractive foliage and unique flowers are reason enough to include this plant in your dry garden. The flowers have been said to look like eye balls, fried eggs, or even, as Eastman writes, “white nests with a central yellow clutch of eggs spilling out.” However you decide to describe it, this is a tough and beautiful plant deserving of a place in the landscape.
- USDA Forest Service: Pearly Everlasting
- Ladybird Johnson Wildflower Center: Anaphalis margaritacea
- In Defense of Plants: Pearly Everlasting
Photos in this post are of Anaphalis margaritacea ‘Neuschnee’ and were taken at Idaho Botanical Garden in Boise, Idaho.
So, you want to petrify some wood, eh? Here is a list of the basic ingredients that you will need:
- A log (or some other chunk of wood)
- Sediment, mud, volcanic ash, lava, or some type of inorganic material in which to bury the log and create an oxygen-free environment
- Groundwater rich in silica (or other mineral commonly found in rocks)
- Additional minerals including iron, copper, and manganese for coloring
- Time and patience (because this is going to take a while – millions of years perhaps)
Petrification refers to organic material being converted entirely into stone through two main processes: permineralization and replacement. First, the log you intend to petrify must be buried completely, cutting off the oxygen supply and thereby slowing the decay process considerably. Over time, groundwater rich in silica and other minerals will deposit the minerals in the pore spaces between the cells of the log. Later, the mineral rich water will slowly dissolve the cells and replace them with the minerals as well. The slower the better, assuring that the textures of the bark and wood and details such as the tree rings will remain visible. After enough million years have passed, the log may find itself exposed, pushed out of the ground by an earthquake or landslide or some other act of nature. What entered the ground as a living or recently dead tree, is now 100% inorganic material. And it is much heavier.
The colors in your petrified log will vary depending on the presence and concentrations of minerals in the groundwater. Cobalt, copper, and chromium will create greens and blues. Iron oxides will give the log hues of red, orange and yellow. Manganese adds pink and orange. During the petrification process, various circumstances can cause the silica to form a variety of crystal structures and other formations within the log. These formations can include amethyst, agate, jasper, opal, citrine, and many others. When all is said and done, your petrified log will be a true work of art.
Petrification is a fossilization process. Thus, a section of petrified wood is a fossil, and it can be used to help paint a picture of what a particular region was like back when the tree was alive. It can also help us gain a better understanding of how life has evolved on this planet. Areas with large concentrations of petrified wood are located throughout the world, each with its own unique story to tell about the tree species once found in the area and the circumstances that led to their petrification. One such location is Petrified Forest National Park in Arizona. The petrified wood found there came from trees living in the area over 200 million years ago.
Is a few million years too long to wait? Scientists have developed ways to petrify wood in the laboratory in as little as four or five days. One such process was developed at Pacific Northwest National Laboratory about a decade ago. It involves soaking a section of wood in hydrochloric acid for two days and then in either a silica or titanium solution for another two days. After air-drying, the wood is placed in an argon gas filled furnace and slowly heated to 1400° Celsius over a period of two hours. It is then left to cool to room temperature in the argon gas. What results is a block of ceramic silicon carbide or titanium carbide. Probably not as beautiful and interesting to look at as the one that took millions of years to form, but cool nonetheless.