Chernobyl Plants And The Exotic World Of Ruderal Species

“Sometimes the best thing you can do is…. nothing. –Oliver Kellhammer, Ecological Artist 

There’s a lesser-known field of botany called the study of ruderal plants, or plants that grow on waste ground, ruins or rubble. Borne by birds, wind or other animals, the weed-like species are the first to colonize lands disturbed by wildfires, avalanches, construction and other ecological disasters. The plants self-sow in abandoned areas, forming impromptu gardens and forests over time, in a clear demonstration of what Mother Nature can do when left to her own devices.

I’ve always been fascinated by this area of study that attempts to understand how these pioneering plants came to be. Back in 1643, the Roman botanist Domenico Panaroli (1587-1657) was interested, too, when he began compiling the world’s first inventory of plants growing in the ruins of Rome’s Colosseum. Of the many species he observed, he discovered that most originated not in Italy, but in North Africa.

Inside view of Rome’s Colossium

In his book titled Flora of the ColosseumPlantarum Amphytheatralium Catalogus, Panaroli identified 337 ruderal plants growing in and around the different climatic zones of the 6-acre colosseum. The lush vegetation, which was thriving without apparent need for cultivation, exhibited a dynamic intermix of native and nonnative species. The surprising findings led Panaroli to hypothesize that the foreign plants had traveled in with birds, or by wind or possibly on the coats of animals brought to fight in the ancient arena.

Daniel in the lion’s den

Two hundred years later, an English doctor named Richard Deakin recorded a total of 420 species growing simultaneously in the ruins. The plants, which he documented in his 1855 book Flora of the Colosseum of Rome, included figs and vines, wild roses, orchids and dianthus, many of which had naturalized in the microclimates of the Roman forum. He wrote:

The object of the present little volume is to call the attention of the lover of the works of creation to those floral productions which flourish, in triumph, upon the ruins of a single building. [ ] Though without speech, they tell of that regenerating power which reanimates the dust of mouldering greatness.

Wild rose, Rosa canina

Today the list of species from the Colosseum has grown to 684. Of these, over two hundred of the species first identified by Panaroli still remain.

Chernobyl

In our lifetime, or at least mine, one of the largest ecological disasters occurred in 1986 in Ukraine when an explosion and fire in the Chernobyl nuclear plant released large quantities of radioactive particles into the atmosphere. The catastrophic nuclear disaster contaminated an area of approximately 1000 square miles in Ukraine, Belarus and Russia. It is now referred to as the Exclusion Zone.

Chernobyl nuclear power plant

In the first decade following the accident, though, scientists began noting an important development in the composition of the area’s microscopic organisms. As a result of their exposure to high levels of radioactive contamination, the bacteria had started mutating more rapidly. And they were beginning to create new radiation-proof forms of life.

The worst-affected woodland, composed primarily of Scots pines, is today known as the Red Forest. (The name comes from the ginger-brown color the trees assumed after absorbing the intense doses of radiation.) Although the majority of the pines were bulldozed and then buried in trenches, today scientists are observing what they call an unnatural selection. New types of plants have started growing in the forest and their biodiversity is increasing.

Plants growing in an abandoned amusement park near Chernobyl

In fact, in the last ten years, the M.G. Kholodny Botanical Institute of NAS of Ukraine has recorded intensive processes of reforestation as well as the presence of more than 40 different trees that have begun appearing in the Red Forest. These include some entirely new species.

Black locust, Robinia pseudoacacia, is now growing in the Chernobyl area.

Left undisturbed by humans, aggressive ecologies of native species, including several new kinds of natural lichen and grasses, have developed. As they commingle with other nonnative groups, the Chernobyl plants are combining to form species that have never before been envisioned. Some of the plants and animals have even evolved a tendency to produce more cancer-fighting antioxidants to help them resist the effects of pervasive radiation: attributes that may one day help humans develop some of their own.

Oliver Kellhammer  is an artist, educator, activist and writer. Through his botanical interventions and public art projects, he seeks to demonstrate nature’s surprising ability to recover from ecological damage. His evolving body of work has taken such forms as small-scale urban eco-forestry, inner city community agriculture and the restoration of eroded railway ravines.

Concrete Island by Oliver Kellhammer

In 2006, Kellhammer created a botanical garden of ruderal plants for the World Urban Forum, which was held in a former heavy equipment plant in Vancouver, British Columbia. For his exhibition, Kelhammer chose a disused corner of the site, a concrete rectangle, where a variety of weeds and other plants appeared to be flourishing. Rubble, garbage and other debris had provided the perfect conditions for ruderal plants such as scotch broom, cottonwood and Himalayan blackberry as well as several species of mosses and grasses to grow.

Kellhammer noted that the plants comprised both native and nonnative species; a reflection of sorts of the city’s Asian, European and native British Columbian inhabitants. To call attention to the plants, he installed botanical labels on the various species with the option to push on a button to connect visitors’ cell phones to recorded information. The Concrete Garden provided interesting insights into the workings of ruderal plants as well as nature’s incredible resiliency.

Yes, Mother Nature is full of surprises. One has only to look to the Colosseum, Chernobyl and innumerable abandoned areas around the world to see the processes of her regeneration, proving that architecture, like all of us, is inevitably ephemeral.

Five Reasons Your Trees Are Failing: A Bartlett Tree Expert Speaks Out

Trees are generally admired for their surface beauty, but their health and vigor springs from what’s underground. That’s according to Dr. Kelby Fite, Director of Research for Bartlett Tree Research Lab in Charlotte, North Carolina, who spoke to Maryland’s master gardeners last week. His lecture entitled ‘Managing the Landscape Below Ground’ provided a wealth of information about how to improve the life of the trees in our landscape. According to Fite, it all starts with the soil. Continue reading

Bees, Wasps and Hornets: Here’s How To Tell The Difference

Four common bees and wasps

What is the difference between bees, wasps and hornets? This is a question I tend to ask myself, especially when surrounded by swarms of hungry yellow jackets while dining outside. I, for one, know from experience that fuzzy honeybees can make excellent garden companions. But, what’s up with their skinny yellow and black striped brethren? Do they have any value? They seem interested only in stinging me. Continue reading

Help Save The Monarchs With These 4 Great Milkweeds

Monarch butterfly on swamp milkweed

Last week, I was manning the booth at the Montgomery County Fairgrounds Demonstration Garden (yes, it’s a mouthful), when someone plopped a tall, spindly plant down onto the table. The plant looked pretty pitiful; the flowers were long gone and the paddle-shaped leaves had circular holes in them. But upon closer examination of the stems, I spotted a string of tiny, lantern-shaped pupae along with a company of black, yellow and white striped caterpillars. The plant was none other than milkweed and the chrysalises contained baby monarchs in the process of forming.

We placed the milkweed next to a grouping of Joe-Pye weed and sat back to see what would happen.

Things aren’t looking up for the monarch butterfly

Monarch butterflies are considered by many to be the ‘king’ of butterflies, with a wing-span of over 4 inches (hence the name, monarch.) But, according to the National Wildlife Federation, their population in North America is in steep decline. Over the past twenty years, monarch numbers have plummeted by an astonishing 90 percent, leading scientists to question what’s happening. They suspect the answer is tied up with milkweed.

Close-up of swamp milkweed, Asclepias incarnata

Why milkweed you might ask? Because milkweed is the host plant for monarchs, and monarch caterpillars will only eat plants in the family. But milkweed has been disappearing, too. Over the last couple decades, large-scale clearing of meadows and prairies for development coupled with heavy pesticide use has resulted in the plants becoming increasingly scarce, placing in jeopardy the tiny population that depends on it for survival.

The problem is so big that according to one National Public Radio (npr) report, monarch populations overwintering in Mexico that averaged around nine hectares from 1995 to 2002, in 2014 took up less than one.*

A migratory insect

Every spring, thousands of Eastern monarchs begin their annual migration across the Great Plains on their journey from Mexico to Canada, covering over 3,000 miles in the process. And every fall, they do the trip in reverse. The insects breed along the way, stopping three times to go through four stages of development: egg, larvae (caterpillar), chrysalis and adult butterfly. The new butterflies live for just four to eight weeks, long enough to fly further north and lay their eggs. Then the next butterfly continues the journey.

Millions of monarch butterflies flying in Mexico

This means that it takes three butterflies to make it all the way to Canada.

Incredibly, the fourth generation butterfly born in Canada lives a bit longer. This is the monarch that migrates back to warmer climates like Mexico. This butterfly lives for six to eight months, long enough for it to start the whole process over again in the spring. (To read more about the monarch butterfly cycle, click here.

A misunderstood plant

The milkweed family, Asclepias, is composed of more than 100 varieties of leafy plants. Tall and upright with long, elliptical-shaped leaves, milkweeds bear dense clusters of vanilla-scented rosy-pink or orange flowers. The plant owes its common name to the milky latex that oozes when a stem is snapped.

Milkweed provides all the nourishment the four generations of monarchs need to transform from larvae into butterflies. The baby caterpillars feed on the leaves until fully grown, and then attach themselves to a stem or leaf to start the process of metamorphosis. Once they hatch, the monarchs move on to other flowers to live out their short life.

Monarch chrysalis hanging from a milkweed stem

In addition to nourishment, milkweed provides other advantages to monarchs. As the caterpillars undergo transformation in chrysalis, they ingest toxic chemicals secreted in the plants’ sticky sap. These chemicals, called cardenolides, provide the caterpillars with a key defense against would-be predators such as birds and mice.

Monarch caterpillar munching on milkweed

Specifically, cardenolides are so toxic and bitter tasting to other vertebrate species that they have learned to associate bad taste with the butterflies’ distinctive orange and black markings. Although as adults, monarchs no longer eat milkweed, they are able to sequester the toxins that they ingested as larvae, providing them with protection against many predators during the remainder of their lifespan.

Monarchs’ distinctive colors help ward of predators

Monarch butterflies only lay one egg per leaf, but they lay eggs on lots of leaves and always on more than one plant. They are mini eating machines. Three days after it arrived to the fair, the caterpillars had devoured the plant they rode in on; in their place hung rows of tiny pupae.

Many of us are familiar with the roadside milkweed, but lesser known is that there are now many beautiful perennial varieties that can enhance your garden while helping you do your part to save the monarch species.

Common milkweed, Asclepias syriaca

Ready to save the monarchs? Here are some great new milkweed varieties to try, available at many local nurseries.

Butterfly Weed, Asclepias tuberosa

This bright orange beauty blooms from May to September. It just won Perennial of the Year for its brilliant flowers, hardy, upright stems and good drought-tolerance.

Butterfly weed, Asclepias tuberosa

Or, for a great yellow variety, try ‘Hello Yellow’, available through White Flower Farm.

Asclepias tuberosa ‘Hello Yellow’

 

Swamp Milkweed, Asclepias incarnata

Swamp milkweed ‘Cinderella’ available at Perennials.com

Or try a mix of hot colors, Asclepias Gay Butterflies Mixture, available at White Flower Farm.

Asclepias Gay Butterflies Mixture

Milkweed generally blooms from June to August. All varieties need full sun and well-drained soil. If you observe caterpillars or chrysalises on your plant, wait until the butterflies have flown away, then simply cut the plant to the ground.

* Monarch populations are measured in hectares, which roughly equal 2 1/2 acres.

 

Pass The Vinegar, I Need To Water My Plants

After 14 days without water, only the plants treated with vinegar survived. NIKEN

Lack of water is becoming an increasing concern both for human and plant life throughout the world. Now comes the news that scientists in Japan have discovered that ‘watering’ plants with vinegar can help them survive longer under drought conditions. I don’t know about you, but I’m reaching for that bottle of white vinegar right now to see if my hydrangeas wouldn’t like a swig.

The Study

Last week, scientists at the RIKEN Center for Sustainable Resource Science (CSRS) published the results of a study that showed huge promise for thirsty plants of the future. Researchers revealed that they had stumbled upon a new biological pathway in certain species that sprang into action in times of water stress. By studying the pathway and the chain of chemical reactions within it, the scientists made the surprising discovery that they could induce greater drought tolerance in certain plants simply by growing them in vinegar.

We all know vinegar’s miraculous properties for cleaning windows and removing stains from carpets, but helping plants cope with drought? Now that is shocking news indeed.

My hydrangea showing signs of water stress 

The study began with a collaborative effort to understand the plant Arabidopsis (thale cress.) A relative of cabbage and mustard, this genus of small flowering plants was the first species to have its entire genome sequenced and is considered a model organism for studying plant biology. Arabidopsis is known for its strong drought tolerance due to a mutation to an enzyme called HDA6 (histone desacetylase6). This allows the plant to grow normally without water for extended periods of time.

Microscopic view of anther of Arabidopsis, also known as thale cress

Initial testing showed that when experiencing drought stress, Arabidopsis uses HDA6 to activate a biological pathway that produces acetate, which is the main component of vinegar. The HDA6 enzyme acts as a switch, controlling which type of metabolic pathway is active. While normal plants are busy using metabolic pathways to break down sugar for energy, in times of drought, the Arabidopsis plants switch to the acetate-producing pathway.

To find out how this switch works in times of water stress, scientists conducted an experiment. They grew normal plants under drought conditions, treating some with water, some with organic acids and others with acetic acid. After 14 days, 70 percent of the plants treated with acetic acid were still living. And all of the other plants had died.

Microscopic view of stem epidermis of thale cress showing hairs and stomata

By measuring the amounts of acetate in the Arabidopsis, the team discovered that there was a direct correlation between the amount of acetate the plants produced and how well they performed under drought conditions. And even more exciting, the team carried out the same experiment on rice, wheat and maize and found that these species’ tolerance increased as well when grown in optimal acetic acid concentrations.

Close-up of rice plant

The implications of this research are huge. In an increasingly water-stressed future, this discovery might offer a simple, low-cost alternative to genetic engineering. I’m not sure if it will help my hydrangeas battle another scorching Maryland summer, but I’ll let you know.

 

 

Shooting The Breeze With The Head Of Versailles’ Kitchen Garden

Antoine Jacobsohn, Head of the King’s Kitchen Garden at Versailles

What if you could walk down the street and, next to the shrubs and other flowers, fruits and vegetables were growing? That’s the hope of Antoine Jacobsohn, Head of the King’s Kitchen Garden at the Palace of Versailles. I spent an afternoon with Jacobsohn recently when he came to DC’s Alliance Française to speak about his role in managing this famous French garden. Continue reading

Trade In Your Lawn For A Low-Maintenance Meadow Garden

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A suburban meadow can help free you from tiresome yard work

These days, many of us are searching for alternatives to conventional lawn and garden care, a chore that has become increasingly dependent on time and maintenance as well as pesticides and other poisons. The suburban meadow offers a beautiful solution to this problem. Continue reading

5 Ways You Can Honor Our Planet on Earth Day

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It’s been a while now since Earth Day first made its debut on April 22, 1970. I vaguely remember the strangeness of being let out of school early to pick up trash in the nearby woods. The idea seemed entirely foreign to us at the time, which means, of course, that we were used to throwing our garbage on the ground. Hard to imagine in this day and age that was the common mindset. Continue reading

Now There’s Proof: Bumblebees Make Bigger Plants

Bumblebee pollinating mustard plant/ Photo: University of Zurich (UZH)

There’s been a lot of buzz in recent years about pollinators, especially of the fuzzy yellow and black kind. Now comes news that bumblebees not only help plants propagate, but they also have a positive effect on their size, fragrance and color. It’s all part of a new experiment by researchers at the University of Zurich that proves bees do it bigger and better. Continue reading

Is the Self-Healing House the Garden of the Future?

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Image via Edwin Indira Waskita

There’s a fascinating image that has stuck with me ever since, years ago, I read the sci-fi novel Goodbye and Thanks For All the Fish (the fourth installation in the series the Hitchhiker’s Guide to the Galaxy.) In the novel, author Douglas Adams describes a four-walled house turned inside out. If you entered the house, you found yourself ‘outside’ in a green space, complete with lawn, benches and walking paths. If you exited the house, you found yourself ‘inside’ in a far less desirable place Adams termed the Asylum. Continue reading