September 3, 2014 by awkwardbotany

Kudzu Ate the South…Now Looks North

In 1876, an Asian vine was introduced to the people of the United States at a centennial celebration in Philadelphia, Pennsylvania. It was a fairly benign looking vine, with its leaves of three and its cluster of sweet pea like flowers, but its exotic appeal must have been quite enticing, because it took off…and not just in popularity.

The plant that caught the eye of these early Americans was called kudzu (or kuzu in Japanese). It is a plant in the genus Pueraria in the family Fabaceae (the pea family). The plants first introduced to the U.S. were likely to have consisted of more than a single species such as P. montana, P. lobata, P. edulis, and others, or were hybrids of these species. They were initially lauded for their ornamental value but soon after were recognized for their potential as animal feed. By the 1930’s, when soil erosion had become a major issue, kudzu was deployed by the U.S. government to combat it. At least 85 million government-funded kudzu seedlings later, and the southeastern portion of the United States had secured a future dominated by this relentless and unforgiving vine.

Innocent and harmless is how kudzu must have first appeared, especially to those looking for a fast growing, large-leaved, vining plant to provide quick shade for porches, offering relief from the sun during those sweltering southern summers. Little did they know, however, if left unchecked, that prized vine could engulf homes and outbuildings, cover and pull down trees and utility poles, and choke out crops and pastures in the matter of a single growing season.

(photo credit: eol.org)

Kudzu was added to the Federal Noxious Weed List in 1997, long after it had established itself throughout the southeastern U.S. It now covers more than 3 million hectares, spreading at a pace of about 50,000 hectares (120,000 acres) per year. It is said that a kudzu vine can grow up to a foot in a single day or about 60 feet in a growing season. It is a twining vine, wrapping itself around any upright structure it can access and relying on that support in order to advance upwards. This gives it the advantage of using more resources for growth and expansion of both roots and shoots rather than on the resource demanding task of producing woody stems. Like other members of the pea family, it gets much of its nitrogen from the atmosphere through a process called nitrogen fixation. Because of this, kudzu can thrive in nutrient poor soils. Kudzu is also drought-tolerant, has leaves that follow the sun throughout the day in order to maximize photosynthesis, reproduces clonally by layering (stems in contact with the ground grow roots and detach from the parent plant), and (in North America) is free from the pests and diseases commonly associated with it in its native habitat. For these reasons and others, kudzu has become one of the most notorious, pervasive, and ecologically harmful weeds in the U.S., costing hundreds of millions of dollars in damages every year.

A close-up of kudzu flowers (photo credit: wikimedia commons)

Foliage and flowers of kudzu (photo credit: wikimedia commons)

One glance at what kudzu has done in the southeastern states, and it is obvious that it is some kind of superweed. I saw firsthand just how overwhelming it can be as I drove through Mississippi several years ago. I didn’t even have to stop the car to investigate. It was easily apparent that it was the dominant species, enveloping every tree for miles alongside the highway. Currently, kudzu can be found in every county in Georgia, Alabama, and Mississippi. But kudzu has a limitation; it doesn’t care much for freezing temperatures. Even though it has been present in parts of northern states – like Ohio, New Jersey, and Delaware – for a while now, it has generally been limited to milder locations, and it certainly doesn’t thrive in the same way that it does in the subtropical climates of the southern states. But that is changing, because the climate is changing.

Average global temperatures increased by about 1.53° F between 1880 and 2012, and this gradual increase is expected to continue for the foreseeable future. Biologists and ecologists are monitoring changes in climate closely in order to observe and predict changes in the biology and ecology of our planet. Invasive species are high on the list of concerns, as climate is often a major limitation to their spread. Now that kudzu has been found in Marblehead, Massachusetts and Ontario, Canada, the fear of kudzu climbing north is becoming a reality.

Kudzu is incredibly difficult to control. It does not respond to many herbicides, and the herbicides that do affect it must be applied repeatedly over a long time period. It is an excellent forage plant, so utilizing grazing animals to keep it in check can be effective. Those who have succumbed to kudzu, acknowledging that it is here to stay, have found uses for it, including making baskets, paper, biofuel, and various food items. A compound extracted from the kudzu root is also being studied as a possible treatment for alcoholism. Kudzu has long been valued for its culinary and medicinal uses in Asia, so it is no surprise that uses would be found for it in North America. However, North Americans who embrace kudzu are taking a defeatist approach. That is, “if we can’t get rid of it, we may as well find a use for it.” This, however, should not negate nor distract from the damage it has caused and continues to cause local ecosystems and the ecological threat that it poses to areas where it is just now being introduced or may soon be introduced due to our warming climate.

Millions of dollars are spent every year to address the effects kudzu has on utility poles (phot credi: eol.org)

Millions of dollars are spent every year to remove kudzu from utility poles and replace poles pulled down by kudzu (photo credit: eol.org)

References:

– Encyclopedia of Life: Pueraria Montana

– Wikipedia: Kudzu in the United States

– Max Shores: The Amazing Story of Kudzu

– U.S. Fish and Wildlife Service: Conservation in a Changing Climate

– NASA Earth Observatory: How Much More Will the Earth Warm?

– Bloomberg: Kudzu That Ate U.S. South Heads North as Climate Changes

August 22, 2014 by awkwardbotany

My Carrion Flowers

In April of last year, a box of stem cuttings arrived in my mailbox. They were sent to me by a friend in Colorado called Sandra (you may know her from one of her many ventures: Greenwoman Magazine, Greenwoman Publishing, Flora’s Forum, etc.). Sandra’s carrion flower had bloomed that spring, a stinky but delightful occasion. In her excitement, she asked if I would be interested in growing some carrion flowers of my own. Not one to turn down the chance to try my hand at cultivating something unusual, I gladly accepted her offer of a few cuttings sent via Priority Mail. Six cuttings arrived shortly thereafter, and upon reading through some instructions on the internet, I nestled them into their new home and hoped they would put down roots and stay a while.

There are several species of plants that are referred to commonly as carrion flower. The plant parts I received from Sandra are in the genus Stapelia (family: Apocynaceae or dogbane family), also known commonly as African starfish flower. There are around 100 species in the genus Stapelia, and they all originate from tropical and southern Africa, mostly in arid regions.

Stapelias are short-lived, low-growing, perennial succulents. Their stems typically stand erect and are produced along stolons (above ground runners), creating a tight clump of stems that appear cactus-like. Each stem has 4-6 flattened vertical flanks, giving it a cross or star shape when looking down from the top. On the outside edges of the flanks are a series of rudimentary leaves protruding from tubercles (wart-like growths), giving the stems a spiny appearance. The stems are usually green but can also be red or mottled with red or purple.

The flowers of Stapelia are the real show. They are produced at or near the base of the stem and have a star-shaped corolla with five fused petals that come to sharp points. The corolla has a wrinkly look and is often hairy, especially along the margins. Flowers can be variations of red, brown, yellow, and purple. In some species they can reach up to 18 inches wide. It is a unique looking flower, but even more unique is its scent. Because Stapelia flowers are pollinated by flies, they emit the scent of rotting animal flesh, an odor that flies can truly appreciate. In fact, flies can be so deceived by the appearance and scent of the flowers that they occasionally lay their eggs on or near them, expecting them to be a food source for their emerging larva.

Stapelia variegate (photo credit: eol.org)

Stapelia variegata (photo credit: eol.org)

Stapelia is easily propagated, especially by stem cuttings. Allow cuttings to dry in a cool, shady location for 48 hours and then stick them in a well-drained potting soil mix. Water moderately (preferably from below by placing the container in a tray and then filling the tray with water). Cuttings should root easily. All six of mine did.

Keep Stapelia in a sunny or mostly sunny location. If you live in USDA hardiness zone 9 or above, you can grow Stapelia outdoors. Otherwise, keep it indoors near a window that gets lots of sun. The main thing you will have to worry about is stem rot due to over watering. Grow Stapelia in a well-drained soil mix, water from below, and allow soil to dry out between waterings in order to avoid this.

Stapelia variegata (photo credit: eol.org)

As for me and my carrion flowers, like I said earlier, all six cuttings rooted. I transplanted one of them. Of the five left in the original pot, one rotted a couple weeks ago and another rotted during the writing of this post. The remaining ones still look healthy, but none of them have grown much since they rooted. The main problem I am having is that my house does not let in much sunlight. What appears relatively bright to me is probably cave-like to my carrion flowers. Until I remedy that situation, they may not grow much, they could continue to rot, and they probably won’t flower any time soon. However, if anything changes and I do get a flower out of them, I will make it a point to let you know. And Sandra will be proud.

August 8, 2014 by awkwardbotany

Trees Are Good For Your Lungs

Trees help reduce air pollution. They do this primarily by pulling gases (like ozone, sulfur dioxide, and nitrogen dioxide) into their leaves and then diffusing them and/or chemically altering them so that they are no longer a direct threat to humans. They also intercept particulate matter, trapping it on the surfaces of their leaves until the wind comes along and blows it away or the rain comes around and washes it into the soil. Trees are filters in this sense, reducing the health threats of our polluted air.

But didn’t I just report on the contribution of urban trees to air pollution via their production of volatile organic compounds? Yes I did. And that remains a possibility; however, according to a study recently published in the journal, Environmental Pollution, the presence of trees is a great benefit to human health despite potential risks. More research is necessary of course, but the consensus so far is that having trees around is a net positive.

Alnus glutinosa, European Alder (photo credit: wikimedia commons)

There have been many studies on the relationship between trees and air quality, but little is known about the extent to which human health impacts are avoided and the related money that is saved as a result of air pollution mitigation by trees and forests. With the aid of computer simulations, researchers at US Forest Service and The Davey Institute used 2010 Census data, tree cover maps from the 2001 National Land Cover Database, US EPA’s BenMAP program, and other data to seek answers to these questions. Their analyses – focused at the county level – involved the 48 contiguous United States.

According to their study, trees and forests removed around 17.4 million tons of air pollution in 2010, which resulted in a health care savings of $6.8 billion. 850 human deaths were avoided, and incidences of acute respiratory symptoms were reduced by 670,000. Ozone and nitrogen dioxide experienced the greatest decrease, while the removal of ozone and particulate matter resulted in the greatest health value. Air pollution removal was greater in rural areas compared to urban areas simply because there is more rural area in the US than urban area; however, the removal of air pollution was found to be more valuable in urban areas due to differences in population density. Resulting health benefits and savings are quite dramatic considering that air pollution removal by trees was only found to improve air quality by about 1%.

There were many things left out in this study though, and the researchers acknowledge this. First of all – as stated earlier – trees have the potential to contribute to air pollution. They emit volatile organic compounds which can result in ozone formation, they can reduce wind speeds which concentrates pollutants, and they produce pollen which is a direct contribution to air quality and a major health issue for those with serious allergies. But trees reduce air pollution in indirect ways as well. For example, by shading buildings, trees can reduce energy demands which results in decreased power plant emissions and a reduction in air pollution.

Quercus sp., Oak Tree (photo credit: wikimedia commons)

Trees can also be negatively affected by air pollution. When particulate matter collects on leaf surfaces, photosynthesis is compromised, limiting a tree’s ability to take gaseous air pollution into its leaves. Urban trees are stressed in additional ways. For example, trees growing near sidewalks, driveways, and roadways deal with serious soil compaction and are often not receiving optimal amounts of water, which can limit their ability to mitigate air pollution. Thus, environmental factors should be considered when determining the relationship between trees and air quality.

This study was conducted at the county level. The researchers acknowledge that more precise predictions could be obtained if analyses were conducted at a finer scale. “Local-scale design of trees and forests can affect local-scale pollutant concentrations.” So, the number of trees, their concentration and configuration, the length of the growing season, the percentage of evergreen trees vs. deciduous trees, etc. all play a role in the extent of air pollution reduction.

While limitations to the study abound, the researchers assert that this initial analysis gives “a first-order approximation of the magnitude of pollution removal by trees and their effect on human health.” Future studies will provide more accurate approximations, but for now I think it is safe to say that trees are good for our health and worthwhile things to have around.

Boise National Forest

This study focused mainly on health issues of the respiratory variety. The positive psychological benefits of plants have been observed in separate studies, and our also worthy of our consideration when determining the health benefits of trees and forests.

August 3, 2014 by awkwardbotany

Drought Tolerant Plants: Blue Sage

If you are considering installing a drought tolerant garden on your property or including more drought tolerant plants in your landscape, one plant that should come standard is blue sage. Its silvery-green foliage, large, abundant, purple-blue flower stalks, and attractive mounded shape, make it an excellent feature in any water-efficient garden bed.

Salvia pachyphylla is in the mint family (Lamiaceae). It has several common names which it shares with several other plants: blue sage, Mojave sage, rose sage, mountain desert sage, giant-flower sage. For this post we will refer to it as blue sage; however, if you’re looking to purchase it, make sure to verify the botanical name. Blue sage is a subshrub that can grow up to 3 feet tall and 3 feet wide. It tends to remain smaller – around 1-2 feet tall – in its native habitat. It is found in the southwestern states of the United Sates on dry, rocky slopes and flats at elevations between 5,000 – 10,000 feet. The leaves are oppositely arranged and covered with fine hairs that lay tightly against the leaf surface giving the foliage its silvery appearance. Like all other sages, the leaves of blue sage are highly aromatic.

The flowers appear in compact clusters on spikes that extend upward from the branches. The inflorescences can be several inches long. They have numerous large, purple bracts that appear in a whorled pattern along the spike. The violet-blue flowers are small but prolific and appear between the bracts surrounding the stalk. Flowering occurs throughout the summer (July-September in its native range). The flowers attract droves of pollinators including bees, butterflies, and hummingbirds. Blue sage is especially beneficial to native pollinators. In fact, while taking photos for this post, I noted that the flowers were being visited by several bumblebees. Its benefit to pollinators is another great reason to include this plant in your landscape.

Blue sage is a very drought tolerant plant. Once it is established it requires only occasional watering throughout the summer in order to keep it looking good. It performs well in a variety of soil types, but like most drought tolerant plants it is best placed in well drained soil. Heavy soils can be amended by mixing in things like sand, lava rock fines, and compost at planting time. It prefers full sun and is winter hardy to USDA hardiness zone 5, especially if planted in an area where the soil is relatively dry throughout the winter. Blue sage is a long lived plant and can be kept in shape by cutting back the spent flowers in the fall. The folks at Plant Select recommend planting blue sage with, among other things, penstemon, coreopsis, and creeping veronica.

Photos were taken at Idaho Botanical Garden in Boise, Idaho.

July 13, 2014 by awkwardbotany

Hundreds of Japanese Plants Threatened with Extinction

Life has existed on earth for at least 3.5 billion years, and during that time there have been five mass extinctions. Currently, we are in the middle of a sixth one. The major difference between the current extinction event and others is that this one is largely human caused, which is pretty upsetting. However, knowing that detail has its upside: if humans are the drivers of this phenomenon, we can also be the ones to put on the brakes.

Biologists have spent the last several decades tracking the current mass extinction, endeavoring to come up with a list of species that have the greatest risks of extinction, as well as lists of species that are at less of a risk, etc. The problem is that factors leading up to extinctions are diverse, and available data for making predictions is lacking, especially temporal data. Recognizing this information gap, researchers in Japan set out to better determine the extinction risk of Japanese flora. Using data from surveys done by lay botanists in 1994-95 and 2003-04, they were able to calculate a trend which indicated that, under current circumstances, between 370 and 561 plant species in Japan will go extinct within the next 100 years.

photo credit: wikimedia commons

The methods for this study, as described in the findings which appeared last month in PLOS ONE, involved dividing Japan into 3574 sections measuring around 100 square kilometers each and covering about 80% of the country. More than 500 lay botanists tallied the numbers of species that were found in each section during the two time periods. 1735 taxa were recorded, and out of those, 1618 were considered quantifiable and used in the analysis.

Japan is home to a recorded 7087 vascular plant taxa. Historically, the extinction rate of plant taxa in Japan has been around 0.01% per year. According to this study, over the next 100 years the extinction rate will rise to between 0.05 and 0.08% per year. Researchers are organizing a third census in the near future in order to monitor the actual extinction rate and better determine the accuracy of this prediction.

Data collected in these censuses was also used to evaluate the effectiveness of protected areas and determine the need for improvements and expansions. Natural parks cover 14.3% of Japan, but only about half of that area is regulated for biodiversity conservation. The researchers found that protected areas do help to reduce the risk of extinctions, but that their effectiveness is far from optimum and that even expanding protected areas to cover at least 17% of the nation (a target set at the recent Convention on Biological Diversity) would not effectively gaurd threatened plant species from extinction.

In their conclusion, the researchers advise not only to expand protected areas but to improve the “conservation effectiveness” of them, and “to improve the effectiveness of them, we need to know the types of pressures causing population decline in the areas.” They go on to list a few of these pressures, including land development and recreational overuse, and suggest that management schemes should be developed to focus on specific pressures.

Japanese Primrose, Primula japonica (photo credit: eol.org)

One thing I found very interesting and encouraging about this study was the recruitment of lay botanists in collecting data. As stated in the findings, “Monitoring data collected by the public can play an essential role in assessing biodiversity.” I am excited by the growing citizen science movement and hope to see it continue to expand as more and more people become interested in science and eager to add to this body of knowledge. In fact, I consider the term “awkward botany” to be synonymous with citizen, lay, and amateur botany. That is precisely why I chose it as the title for my blog. So, in short, expect more posts involving citizen science in the future.

You can read more about this study on John Platt’s blog Extinction Countdown at Scientific American.

July 6, 2014 by awkwardbotany

Corpse Flower Blooms Again

It is not often that a plant in bloom makes headlines, but that is precisely what happened last week when another corpse flower bloomed at Missouri Botanical Garden. Amorphophallus titanum, commonly known as titan arum or corpse flower, is a rare species, both in cultivation and in the wild. It also rarely flowers, and when it does, the bloom only lasts for a few short days. It has the largest known unbranched inflorescence, and its flowers give off the scent of rotting flesh. For all these reasons, it is understandable why a blooming corpse flower might make the news.

Titan arums naturally occur in the western portion of an Indonesian island called Sumatra. Their future is threatened because they occur in rainforests that are currently being deforested for timber and palm oil production. Deforestation is also threatening the survival of the rhinoceros hornbill, a bird that is an important seed distributor of titan arums. Today there are a few hundred titan arums in cultivation in botanical gardens throughout the world. They are a difficult species to cultivate, but their presence in botanical gardens is important in order to learn more about them and to help educate the public about conservation efforts.

(photo credit: eol.org)

Titan arums are in the arum family (Araceae), a family that consists of around 107 genera including Caladium (elephant ears), Arisaema (jack-in-the-pulpits), and Wolffia (duckweeds), a genus that wins the records for smallest flowering plant and smallest fruit. Titan arums are famous for their giant inflorescence, which can reach more than 10 feet tall. The flowering stalk is known botanically as a spadix, a fleshy stem in the shape of a spike that is covered with small flowers. The spadix of titan arums are wrapped with a leaf-like sheath called a spathe. Upon blooming, the temperature inside the spathe rises and the flowers begin to release a very foul odor, similar to the smell of rotting flesh. This attracts pollinating insects such as carrion beetles, sweat bees, and flesh flies, which get trapped inside the sheath and covered with pollen. After a few hours the top of the spadix begins to wither, allowing the insects to escape, off to pollinate a neighboring corpse flower [the spadix includes male and female flowers, which mature at different times in order to prevent self-pollination]. Once pollinated, the flowers begin to form small red fruits which are eaten by birds. The seeds are then dispersed in their droppings.

The large, stinky inflorescence is not the only structure that gives titan arums their fame. They are also known for their massive single leaf, which can reach up to 20 feet tall and 15 feet wide, the size of a large shrub or small tree. All of this growth is produced from an enormous underground storage organ called a corm. The corms of mature titan arums typically weigh more than 100 pounds, with some known to weigh more than 200 pounds. Titan arums bloom only after the corms have reached a mature size, which takes from seven to ten years. After that they bloom about once a year or once every other year, depending on when the corm has accumulated enough nutrients to support the giant flowering structure.

Below are two time lapse videos of titan arums in bloom. The first is from Missouri Botanical Garden, and the second is from United States Botanic Garden.

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June 28, 2014 by awkwardbotany

Wildflower Walk: June 2014

I spent last weekend in a cabin outside of Garden Valley, Idaho. I was there for a wedding and so most of my time was occupied with that. However, anxious to explore, I found a brief moment to step out and observe the surrounding plant life. The cabin and an adjacent campground were located in an area that, before the economic downturn in 2008, was to become a major housing development. Because of this (and possibly other things), the area showed lots of signs of human disturbance, particularly the large number of introduced plant species. Fortunately, despite feeling like I was walking through a weedy field, I did come across a few patches of native plants. I may have to return sometime to get a better look at things because I wasn’t able to identify everything that I saw and I’m still not exactly sure what species of lupine and buckwheat I was looking at. Either way, the plants in the following pictures are a few of the things I found.

Aristida purpurea (purple threeawn)

Aristida purpurea (purple threeawn)

Lupinus sp. (lupine)

Eriogonum sp. (wild buckwheat)

Amelanchier alnifolia (Saskatoon serviceberry)

Don’t let my walk through a weedy field dissuade you. Garden Valley is an incredibly beautiful location. It sits adjacent to the South Fork of the Payette River and near the western edge of the Boise National Forest. It is an area worthy of exploring, which is why I plan on visiting again soon. I recommend you do too.

Previous Wildflower Walks:

–Spring 2013

–June 2013

–American Penstemon Society Field Trip

–September 2013

June 20, 2014 by awkwardbotany

Ethnobotany: Marigolds

Marigolds are easily one of the most commonly grown annual flowers. They are so common and pervasive, in fact, that they are often overlooked and underappreciated. I, for one, had discounted marigolds long ago, seeking instead for plants considered to be more rare, unconventional, and unusual to place in my garden. But then I started looking into this commonplace plant and, to my surprise, discovered that marigolds have great cultural significance in countries all around the world, both currently and historically. Suddenly, marigolds don’t seem quite so ordinary.

Marigold is a common name for plants found in several genera, but in this case I am referring to plants in the genus, Tagetes, which is in the family, Asteraceae (also known as the sunflower family). Tagetes is a genus composed of at least 42 species, all of which are native to North and South America. Plants in this genus range in height from a few inches to as tall as 6 feet or more. Like most other species in the sunflower family, their flowers appear to be single blooms but are actually clusters of two different types of smaller flowers: ray florets and disc florets. The flowers can be orange, yellow, golden, white, and, in some cases, maroon or with maroon accents. The leaves are usually finely divided and either oppositely or alternately arranged, and the leaves, stems, and flowers are highly aromatic. Marigolds grow in a variety of soil types, even those with minimal fertility. In gardens, they will perform best if they are grown in well-drained soil in full sun and are watered and deadheaded regularly.

Aztec Marigold (Tagetes erecta)

Even before marigolds gained worldwide popularity, they were commonly used among the people in their native range. They were of particular interest to the Aztecs, who considered marigolds a sacred plant and used them in religious ceremonies. Marigolds became known as the flower of the dead and are still used today during the Day of the Dead to adorn altars and graves. Marigolds were also an important medicinal plant for the Aztecs, especiallly T. lucida, which they used to treat fevers, stiffness, blisters, and various other ailments.

Spanish and Portugeuse explorers were introduced to marigolds by the Aztec people. The explorers brought marigolds back to their homelands and quickly spread them throughout Europe and into Africa and Asia. It was in Europe that they were given their common name, Mary’s gold, referring to the Virgin Mary and the color of the flowers. At the beginning of the 16th century, Portuguese explorers established a colony in India. The marigolds they brought with them have become a huge part of Indian culture and other cultures in that region. Today there are many large marigold farms in various parts of India, and marigolds are used widely to make garlands and other decorations for weddings, festivals, and religious ceremonies, as well as in foods and dyes.

Marigold Garlands (photo credit: wikimedia commons)

The flowers and leaves of marigolds are edible and have culinary and medicinal uses in many countries, especially those in South America. T. lucida and T. minuta are particularly popular for these uses. Marigold flowers have a citrus-like flavor, and T. tenufolia ‘Lemon Gem’ is said to be the best tasting marigold (although, having never eaten marigold flowers myself, I have no personal experience to back that up). The essential oil of T. minuta is frequently used in the fragrance industry and as a medicinal oil. However, T. minuta has also become naturalized in many parts of the world, including Africa, Asia, and North America, and is considered an invasive weed species in these areas.

Marigolds are often planted in vegetable gardens because they are assumed to repel pest insects and/or attract beneficial insects. Little research has been done to back up these claims. The one thing that I was able to confirm is that they have been found to reduce populations of nematodes in the soil. However, just interplanting marigolds among vegetable plants is not enough; instead, a large number of marigolds would need to be planted and then tilled into the soil in order to have the desired effect. Surely marigolds attract pollinating insects, but do they repel pests (apart from nematodes) or attract other beneficial insects? If you have an answer to this, comment below.

Tagetes minuta (photo credit: eol.org)

I have marigolds in my garden this year, partly due to my newfound appreciation of them. If you’d like to see pictures of my marigolds, along with pictures of other things I’m growing, seeing, and doing, subscribe to my tumblr and/or follow me on twitter.

May 31, 2014 by awkwardbotany

Drought Tolerant Plants: Fernbush

The first of many plants to be profiled in this series on drought tolerant plants is Chamaebatiaria millefolium, known commonly as fernbush or desert sweet. Fernbush is a shrub that is found in most western U.S. states, generally in locations that are dry and rocky with sandy or gravelly soils. However, it also occurs in sights with loam or clay loam soils, making it a plant that is not too finicky about soil types. It is found at a wide range of elevations (from 3,000 feet up to 11,000 feet) and in a wide variety of plant communities, including lodgepole pine subalpine forests, juniper-pinyon pine woodlands, mountain mahogany-oak scrublands, and sagebrush steppes. It is occasionally browsed by certain animals, but not enough to be considered an important food source. Instead, its major wildlife value is providing cover for birds, small mammals, and antelope.

Fernbush is by far one of my favorite shrubs. Its the leaves that make it so interesting. As the common name suggests, the leaves look just like little fern fronds, and considering that ferns tend to be associated with shady, moist environments, it seems strange to see a fern-like bush growing in full sun in a dry, rocky site. Alas, fernbush is not a fern, but instead a shrub with very cool leaves.

Fernbush grows to about as wide as it does high (between 1-3 meters), and depending on where it is growing it is evergreen or semi-evergreen, dropping the older leaves from the lower portions of its branches during the winter. Its bark is smooth and russet or cinnamon-colored. Flowers appear in clusters at the tips of branches in mid to late summer and are small, white or cream colored, and rose-like with five petals.

The fruit of fernbush is called a follicle and contains very small seeds, mere millimeters in size. The spent flower stalks are attractive in their own right and provide great winter interest. They can be pruned off in the spring in preparation for new flower stalks and to keep the plants looking good.

Fernbush is very drought tolerant. Once its established, it needs very little (if any) supplemental water. It is likely that the leaves of fernbush give it this trait. They are small and finely divided, as well as being hairy and resinous. Physical adaptations such as these reduce water loss through transpiration, which helps the plant use available water more efficiently. Though not very commercially available, fernbush, with its unique appearance and late summer blooms, is a great addition to waterwise gardens and landscapes.

Fun Fact: Chamaebatiaria is a monotypic genus, meaning that it is a genus consisting of only one species. In this regard, Chamaebatiaria millefolium is a true rarity.

April 28, 2014 by awkwardbotany

Drought Tolerant Plants: An Introduction

Water is a precious natural resource and an essential element for life on earth. Demand for water increases dramatically as human population grows and fresh water sources become polluted. Awareness of our reliance on water is especially heightened during times of drought, like the one that California residents are currently experiencing. Some regions of the planet are inherently dry. The region where I live (Boise, Idaho) receives on average about 12 inches of precipitation annually. Compare that to a place like Pensacola, Florida which receives around 65 inches annually, or El Paso, Texas which is lucky to get around 8 inches of rain a year. So whether it is out of necessity (enduring a drought or living in a dry climate) or simply the desire to be a responsible citizen of planet earth, many people are choosing to incorporate more drought tolerant plants in their landscapes in an effort to conserve water.

In the early 1980’s, landscaping with drought tolerant plants was given the name xeriscaping by the Denver, Colorado water department. These days terms like water-wise gardening and water efficient landscaping seem to be more popular. The initial vision that many people may have of a landscape planted with water efficient plants is one filled with desert plants like cacti, yuccas, and other succulents along with drab shrubs like sagebrush. While landscapes like these can actually be quite attractive (see Plantasia Cactus Gardens), modern water-wise gardens do not have to be so cacti-centric. As interest in water efficient plants has grown in recent years, the horticulture industry has been busy introducing a wide variety of plants that are not only drought tolerant but are lush, green, and full of color.

Plantasia Cactus Gardens – Twin Falls, Idaho

Plants that live in regions with frequent or extended droughts are called xerophytes. They have developed a variety of mechanisms that allow them to survive and even thrive in these regions. Ecologists call these mechanisms strategies, or sets of coordinated adaptive traits. In future posts I intend to profile specific drought tolerant plants so that we can get to know them on a more individual basis. For now I will provide a brief overview of the strategies plants use to cope with low water environments.

-Alternate Photosynthetic Pathways: Conventional photosynthesis is inherently inefficient when temperatures are high and water availability is low. Plants that evolved in hot and/or dry environments have developed alternate photosynthetic pathways in order to overcome these inefficiencies. These alternate pathways involve utilizing a different protein to fix carbon, splitting the photosynthetic process into two separate cells, and collecting carbon dioxide at night then converting it to sugars during the day. Learn more about the different photosynthetic pathways here.

-Drought Avoidance: Many desert plants live most of their lives as seeds hanging out on the desert floor waiting for rain. These are seeds of short-lived annual plants that sprout and grow when the rainy season comes around. They flower and set seed and are gone by the time the dry season returns. Birdcage evening primrose (Oenothera deltoides) and desert sand verbena (Abronia villosa) are examples of these desert ephemerals.

-Drought Dormancy: Some desert trees and shrubs shed their leaves during dry periods, and then put out new leaves when rains return. This is called drought deciduous. Other desert plants live out the dry season as fleshy roots or underground stems, putting out foliage only when conditions are favorable. Arrowleaf balsamroot (Balsamorhiza sagitatta) is a good example of this; it spends much of the year as a taproot with little or no sign of its existence above ground.

Arrowleaf Balsamroot – Balsamorhiza sagittata

-Physical Adaptations: Desert plants have many physical adaptations that allow them to survive in hot, dry climates. The thick, fleshy leaves of cacti and other succulents store water for future use. The roots of some desert plants are shallow but horizontally extensive in order to capture water more effectively when rains come. The roots of other desert plants extend deep into the ground, some (like the roots of mesquite, Prosopis spp.) even reach as deep as the water table. Palo verdes (Parkinsonia spp.) are drought deciduous trees or shrubs that have photosynthetic bark that can keep photosynthesizing even when leaves are not present. Other adaptations include small leaves, hairy leaves, dull colored leaves, and waxy leaves all of which help to reduce water loss and improve the efficiency of photosynthesis.

Drought tolerant sedums (Sedum spp.) with their shallow roots and succulent leaves are ideal for use on green roofs where temperatures are often high and water is limited.

Learn more about how plants cope in low water environments from Arizona-Sonora Desert Museum.

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