Gardeners and farmers know that healthy plants need good soil and the right amounts of both water and sunlight. But green roofs are intentionally built with an engineered soil-like substance that more closely resembles a pile of rocks than rich, moist potting soil.

To make matters worse, the tops of buildings are often blindingly sunny and very hot in the summer. So how do plants like grasses and wildflowers survive in this type of harsh environment?

PHOTO: Cactus and allium grown on green roof.

Cactus and other succulents retain water in their tissues. Ornamental onion (Allium) species have underground bulbs that help them get through cold winters and dry summers.

Not all plants will grow on a green roof, even in the temperate Midwest. Most plant species that are successful in the desert-like habitats of green roofs have beneficial adaptations that allow them to absorb and store water and nutrients. Some have succulent leaves with thick waxy coatings to prevent water from evaporating. Others have roots that grow horizontally rather than vertically to maximize the areas from which they absorb water and nutrients. Some use a modified type of photosynthesis to prevent water loss during the hottest and driest part of the day. Still others use bulbs or underground tubers to store nutrients during the long cold winters. Some species may even form partnerships with special fungi in the soil that help their roots with more effective absorption.

While plant species evolved to develop these various adaptations on the ground, such traits serve the individual plants very well in the harsh environment of a green roof. The next time you visit a green roof, you might see a striking diversity of species but you won’t see any wimps. No, these plants are both beautiful and tough. 

PHOTO: Shortgrass prairie plants grown on a rooftop garden at shallow depths.

Even in very shallow soil and full sun, some plants that normally grow in shortgrass prairies are able to grow and reproduce. (This is from some of my research at Loyola University.)

PHOTO: PCSC green roof in summer 2015.

Plants can be both tough and beautiful on green roofs. (This photo is of the Plant Science Center last summer.)

Find more of the best plants for green roofs on our Pinterest board, and see Richard Hawke’s Plant Evaluation Notes for the plants that performed best on our green roof.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

Several decades ago, an osprey would be a rare—if not impossible—sight in Cook County in the summer. But now, thanks to the ban on certain pesticides (including DDT), and the creation of osprey nesting platforms, the fish-eating bird is breeding again in local forest preserves.

The osprey looks somewhat like an adult bald eagle, but doesn’t have the eagle’s full white head or tail. Instead, it has a broad brown band through the eye, a brown back, and white belly. An osprey flies with a crook in its wings. Immature bald eagles, with their mottled black and white plumage, can easily be mistaken for ospreys. In summer, visitors can watch an osprey (Pandion haliaetus)—with its 6-foot wingspan—soar above a lake, then plunge in to snatch a meal with its talons to bring to its young. 

PHOTO: Osprey in flight.

Osprey in flight
Photo © Carol Freeman

Once endangered in Illinois, the osprey disappeared as a breeding bird from Illinois about 60 years ago. Scientists think, as with the bald eagle, that when the osprey ingested certain pesticides, the chemicals caused its eggs to thin and crumble during brooding. After DDT was banned, state biologists hoped the osprey would return to breed in Illinois. But the bird needed some help, including cleaning up local waterways and providing nesting areas.

In the 1990s, Cook County Forest Preserves officials, following the lead of biologists in other states, began erecting osprey nesting platforms—40-inch-wide platforms atop 50-foot-tall posts—in the preserves, hoping the ospreys would use them to nest.

It worked. The tall structures gave the ospreys a 360-degree view of their surroundings, something scientists say the birds need when choosing a nesting spot. Today, at least a dozen osprey pairs breed in Cook County, with several more in other nearby counties.

This year, the Chicago Botanic Garden installed an osprey nesting platform, and is waiting to see if a pair will find it to their liking.

According to officials of the Cook County Forest Preserves, 12 osprey pairs bred on man-made platforms in the county in 2014, including at Long John Slough at the Little Red Schoolhouse in Willow Springs. A pair of osprey tending to their nest atop a platform was photographed at Saganashkee Slough in the Palos Preserves this year by Wes Serafin, a long-time proponent of helping ospreys return as a breeding species to Cook County.

PHOTO: An osprey keeps a tight grip on lunch.

An osprey keeps a tight grip on lunch.
Photo © Carol Freeman

The ospreys return in April, often to the same platform they used the previous year. They build a nest of sticks atop the platform, adding new ones each year. The female lays three to four eggs, which hatch in about 38 days. While she broods, the male fiercely defends their territory and brings food to his mate. The young remain in the nest for about two months, begging constantly for food. Then they take their first flights off the platform.

Watching an osprey grab a meal can be fascinating. The bird appears as if it is going to plunge head-first into the water, but then it straightens its head and grasps the fish with its talons. Two forward-facing and two backward-facing toes have sharp spines that enable the bird to clutch the fish. Occasionally an osprey will grab a fish too heavy for it to carry, in which case the osprey might drop it, and try for another meal.

The osprey that nest in northern Illinois in summer spend winters in Florida, Mexico, and South America.

The Illinois Department of Natural Resources is now in the fourth year of their program designed to bring more osprey to the state to increase the number of breeding pairs.

The osprey is the July bird species highlighted by the Forest Preserves of Cook County. Come #birdthepreserves with the FPDCC; view the list of upcoming events for free events near you.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Those of us who are Star Wars fans know just how powerful genetic cloning can be. 

Obi-Wan Kenobi’s discovery of a secret clone army illustrated the power of advanced cloning technology. That army of genetically identical clone warriors went on to become the face of the epic Clone Wars. Meanwhile, in a galaxy much closer, plants are also equipped with the ability to copy themselves as a form of reproduction. This form of asexual reproduction is very common in the natural world, and just as powerful to an ecosystem as a clone army is to a galaxy. 

PHOTO: Clone trooper.

This clone may not take over your Garden…

PHOTO: Red Monarda (beebalm).

…but this Monarda might!

Clonality is a form of plant growth that results in genetically identical individuals.

Unlike in sexual reproduction, clonal individuals often spread horizontally below ground via unique root systems. Above ground, these plants appear to be distinct individuals, but beneath the soil surface, they remain connected, as clones of the same original plant.

The Pando, or "Trembling Giant," is a colony of clonal quaking aspens roughly 80,000 years old, in Fish Lake, Utah.

The Pando, or “Trembling Giant,” is a colony of clonal quaking aspens (Populus tremuloides), roughly 80,000 years old, in Fish Lake, Utah. All the trees are a single living organism sharing one massive root system. Photo by By J Zapell via Wikimedia Commons.

From a plant’s perspective, there are many benefits to clonal growth. For example, in an environment with limited pollinators to facilitate sexual reproduction, it might be better to take matters into your own hands and make a copy of your already awesome self. On the other hand, a vulnerability in one clone (for example, to a fatal fungal outbreak) is just as likely to affect all of the other clones, because they share the same genetic makeup. It is important to note that there are ecological downsides to clonality as well. Many invasive species do well in foreign environments because asexual reproduction enables them to reproduce very quickly. Thus, just as we see in Star Wars, clones can either be a powerful asset or a potent enemy.


Abigail WhiteAbbey White is a graduate student working with Andrea Kramer, Ph.D., and Jeremie Fant, Ph.D., developing genetically appropriate seed mixes of vulnerable plant species for restoration.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

Cultivating Nostalgia

Jasmine Leonas —  June 30, 2016 — 7 Comments

The Garden’s head of urban agriculture took a trip to Cuba and reminded me of my culture’s resiliency and connection to gardening.

How do you farm when you have little to no resources? Cubans “inventan del aire.”

Literally meaning “inventing from air,” this is the philosophy that is required to get by in Cuba.

Angela Mason, the Garden’s associate vice president for urban agriculture and Windy City Harvest, traveled to Cuba to see firsthand how the farmers there create and maintain collective farms. These farms provide much-needed produce for a population that lives without what we’d consider the basics in the United States. The average hourly wage in the Chicago area is around $24.48. That’s more than the average monthly wage in Cuba.

“Before going, I didn’t understand why people would risk their lives getting on a raft and floating 90 miles,” she said. “But when you see the degree of poverty that some of the people are living in, it’s heartbreaking.”

Angie recounted to me the details of her trip; the people she met, all of whom were welcoming and warm, and the places she saw. She visited several farms just outside of Havana and another in Viñales, in the western part of the country.

PHOTO: Angie Mason, Fernando Funes and Madeleine Plonsker in Cuba.

Angie Mason, associate vice president Urban Agriculture/Windy City Harvest (center), poses with Cuban trip liason Fernando Funes, and Madeleine Plonsker, a member of the Garden’s President’s Circle who has visited Cuba many times and who helped Angie put the trip together.

Poverty in Cuba means the farmers there grow without supplies and tools that are standard here. But they are still able to create beautiful and sustainable harvests through ingenuity. For example, Angie asked one of the farmers she met what he used to start seeds. He showed her dozens of aluminum soda cans that he’d cut in half. One farmer dug a well by hand. He then used the rocks he dug out to build a terraced garden.

PHOTO: Isis Maria Salcines at her farmer co-operative, Organopónico Vivero Alamar in Havana, Cuba.

Isis Maria Salcines at her farmer cooperative, Organopónico Vivero Alamar, in Havana, Cuba

PHOTO: Finca Marta, Fernando Funes' farm outside of Havana, Cuba, in the province Artemisa.

A glimpse of Finca Marta, Fernando Funes’s farm outside of Havana, Cuba, in Artemisa Province

I asked Angie many questions about her trip and what she saw, because I relish every detail I can learn about Cuba, the country where both of my parents were born.

The reasons for Angie’s trip felt especially close to my own family’s heritage, because I come from a long line of farmers on both sides. My mother’s family had a farm in the province of Matanzas. My father’s side did as well, in the more rural province of Las Villas. Both properties have since been seized by the Cuban government, as was all private property after the revolution in 1959. Neither one of my parents has been back to visit since they moved to the United States as children (my father was just a few years old and my mother was 11) so the stories they can share are scarce. The only tangible evidence of childhoods spent in the Cuban countryside are a handful of faded photographs: my mom riding a horse when she was in kindergarten; my father in diapers and running around with farm dogs. And as each year passes, the memories of Cuba are farther and farther in past.

PHOTO: My mother and grandparents and uncle on the family farm in Matanzas province with my grandfather's most memorable purchase: his Jeep.

My mother and grandparents and uncle on the family farm in Matanzas province with my grandfather’s most memorable purchase: his Jeep

Two of my grandparents, both now deceased, had many stories to share with me as well. My maternal grandfather and my paternal grandmother were fixtures in my life and both often shared stories of their lives before the United States and growing plants and food in the fertile Cuban soil. It’s a talent that apparently never leaves a person, even if they change their country of residence, because both had beautiful backyard gardens at their homes in Miami.

My grandmother had a knack for flowers. The bougainvillea in her yard was always resplendent. Hydrangeas were the centerpieces at my sister’s wedding shower; months later the plant repotted and cared for by my grandmother was the only one that thrived. My grandfather leaned more toward the edible. His yard was full of fruit trees. Whenever he’d visit, he usually brought something growing in the yard: fruta bomba (more commonly known as papaya), mamoncillos, or limon criollo (a type of small green lime).

PHOTO: My grandfather and uncle, circa 1940s in Bolondron, Cuba.

My grandfather and uncle, circa 1940s in Bolondron, Cuba

Growing up, I always associated the cultivation of plants, whether flowers or fruit, as just a part of their personalities. Gardening was a hobby they enjoyed. While that was true, I realized later that it was also an activity that kept them connected to Cuba. As long as they could grow the plants they remembered from back home, that life was not completely gone.

My grandparents, as well as parents, cousins, aunts, uncles, and pretty much most people I’m related to, have all tapped into their resiliency to make it as immigrants in the United States and adapt to their changed lives. The same personality trait that allows a Cuban farmer to grow vegetables without any tools has gotten my family through decades of living outside of Cuba. No matter the situation, members of the Cuban diaspora “inventan del aire.” It’s how people survive in Cuba, but it’s also how Cubans outside of the country get through exile.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

In the race to save native plants like purple New England aster and fragrant American mountain mint, the Chicago Botanic Garden freezes seeds for future use—but will frozen seeds be able to grow after hundreds of years in storage? Researchers are trying to find out.

Environmental threats such as climate change have caused thousands of plants to become rare or endangered. The tallgrass prairie, which has lost 96 percent of its land to agriculture and other human activities, is one of the earth’s most endangered habitats. By preserving seeds in the Garden’s Dixon National Tallgrass Prairie Seed Bank, researchers are working to ensure that native species don’t disappear in the wild.

Inside the seed vault at the Dixon National Tallgrass Prairie Seed Bank.

Inside the seed vault at the Dixon National Tallgrass Prairie Seed Bank.

In winter 2015–16, two students from the Garden’s graduate program, which is offered in collaboration with Northwestern University, helped with the Seed Bank’s first germination trials. In the trial, a sampling of our oldest seeds was removed from deep freeze—a vault at minus 4 degrees Fahrenheit—and placed in favorable growing conditions to see if they would germinate after 13 years of dormancy.

Alicia Foxx germination trials.

Graduate student Alicia Foxx hard at work counting…

Alicia Foxx germination trials.

…and removing seeds that have germinated on an agar medium.

The results? Species such as New England aster (Symphyotrichum novae-angliae), water speedwell (Veronica comosa), and American mountain mint (Pycnanthemum virginianum) germinated well. Species such as enchanter’s nightshade (Circaea lutetiana) and New Jersey tea (Ceanothus americanus) did not germinate; more research is needed to determine whether these seeds did not germinate because we were unable to figure out how to break their dormancy.

 

Graph showing results: Seed sample sizes for trial were either 24, 60, or 75 seeds, depending on the number of seeds in the collection.

Seed sample sizes for trial were either 24, 60, or 75 seeds, depending on the number of seeds in the collection.

The results show that seed collection is an efficient and cost-effective way to preserve biodiversity for future generations; experts predict that many of our native seed can survive hundreds of years in a seed bank (we’ll repeat the germination test in another ten years). Meanwhile, if you’re interested in joining our team and helping with the critical work of seed collection or banking, contact us

Download/read the full results here: Germinating Native Seeds from the Dixon National Tallgrass Prairie Seed Bank.


©2016 Chicago Botanic Garden and my.chicagobotanic.org