Most of us remember chlorophyll from science class, as the chemical that makes leaves green. But ask why leaves turn color in the fall, and we get vague quickly. Colder temperatures? Shorter days? True, but there’s more to the story.
American smoke tree (Cotinus obovatus) turns a brilliant yellow late in the season—after it has gone through burgundy and bright red.
A summer leaf, full of chlorophyll, looks green. But once chlorophyll production stops in fall, the colors overwhelmed by green are revealed: yellow, orange, or brown, the colors of carotenoid chemicals.
Reds, crimsons, and purples happen when sugar is trapped in the leaves. As sugar decomposes, it creates chemicals called anthocyanins.
According to Boyce Tankersley, director of living plant documentation, “Plant physiologists have understood the environmental factors that lead to fall color for many years. However, each of the 1,391 different taxa of trees and 2,319 taxa of shrubs here respond to these environmental signals in slightly different ways: new ‘arrivals’ join the display of fall colors on a daily basis. It’s a constantly changing tapestry of color from September to November!”
Other factors come into play too: nighttime temperatures, soil moisture, the tree’s own genetics, and, of course, the weather. A warm and dry September has meant a late start for color this year. Don’t miss a chance to see the full palette of fall color happening now at the Chicago Botanic Garden—take a fall walk or use our virtual guide: our Garden Guide app.
Check out our infographic below for the full fall story in living color.
Maps had been followed, clues tracked, and early this summer the fortune was found.
Standing on the far side of a hummock swamp in Delhaas Woods in Bristol, Pennsylvania, Andrew Bunting had located a unique magnolia tree population on the edge of fading away. He had discovered the treasure he set out to find. Often, this is where the story ends. But when the prize is an elusive plant sought by scientists nationwide, this is where the story begins.
Andrew Bunting collecting sweetbay magnolia samples in Delhaas Woods, Bucks County, Pennsylvania.
Bunting, the assistant director and director of plant collections at the Chicago Botanic Garden, was on day three of a nine-day adventure across the East Coast to collect northern populations of Magnolia virginiana var. virginiana L.
Bunting welcomes any opportunity to stroll the Garden campus. “I like all the Gardens, of course, but there are a few favorites,” he admitted. “Part of me likes horticulture and part of me likes the scientific evaluation side of things.” He often stops through the Heritage Garden with a nod to statue of Carolus Linnaeus and the Bernice E. Lavin Plant Evaluation Garden.
After locating a group of trees in Delhaas Woods, he and his team took cuttings from new growth and packed them into their bags. The murky waters that now stood between them and a successful exit from the overgrown site were deep and dangerous, and wading out was not an option. They had no choice but to leap between hummocks—floating islands—of knotted blueberry vines, wild roses, and other invasive plants to reach stable ground.
It’s all in a day’s work for Bunting, who has gone on wild plant-collecting trips around the country and world during his career. Days after returning home, he explained that this adventure was no more tame than those in tropical jungles. However, the importance of this collection made it all worthwhile. The target species, commonly called sweetbay magnolia, is generally underrepresented in living collections and arboreta. That means that if it is lost in the wild due to extreme weather or other threats, there is no backup. It could be gone for good.
A sweetbay magnolia tree stands out in Delhaas Woods, Bucks County, Pennsylvania.
By taking plant samples from the field, he and his team hope to grow new generations of sweetbay magnolia plants that can be safely maintained in secure locations long term and used to study and potentially boost the wild populations in the future.
The success of the trip required more than one stop. The team visited multiple locations, collecting from several plant populations across the northern range of the species. Their goal was to collect trees with novel traits, or genes, which would be beneficial for future breeding.
When the team navigated the swamp, their spirits were still high from an especially unique collection they made the day before in the Michaux State Forest, about 125 miles west of Philadelphia. There, they had carefully taken cuttings from a population of state-threatened magnolias that grows far from any other. “I’m hopeful that some of our work may lead to help figure out why that population is where it is,” remarked Bunting, who theorized that the population may have had a broader range millions of years ago and retracted to the coastal plain. He hopes that future DNA tests of the samples will provide answers by clarifying genetic similarities and differences between this and other populations they collected.
Moving into New Jersey, he and his team next gathered additional cuttings. Working closely with project partner Joe Rothleutner, tree and shrub breeder at the Morton Arboretum, and other local experts who joined them along the way, Bunting assembled a detailed logbook to accompany the physical samples.
Magnolia virginiana var. virginiana L. in Michaux State Forest, Pennsylvania.
At every collection location, each team member played a specific role to capture information about the site; from the type of soil to the slope of the land to a description of the local ecosystem, and a list of associated plants. At each site, two 10-inch plant samples, ideally with forming fruits and/or flowers, were pressed between cardboard and labeled for future storage in a herbarium. Other samples were packaged for propagation. The collection project was funded by the U.S. Forest Service and American Public Gardens Association (APGA).
The challenges along the way made every discovery that much sweeter. “What’s nice is you all kind of bring your own expertise and experiences and figure out how to navigate the areas and how to extricate yourself from the areas,” said Bunting. “What’s great about the collecting trips is that you can do a lot of front-end research but there are always surprises,” he added.
On the final leg of the journey, the team members found themselves wearing knee-high boots in the thigh-high waters of a sphagnum swamp in Staten Island. Sinking in deeper with every step, they waded through, only to find no evidence of magnolias. Swatting away mosquitoes and dodging deer ticks, they navigated a thick understory of sharp phragmites reeds and Japanese knotweed to make their escape.
An extended telescopic pole is used to take cuttings of the current season’s plant growth.
In all, they returned home with representatives from nine populations and 850 unique cuttings.
Many of the species on display at the Garden today were once such wild treasures, explained Bunting, who, after years working for esteemed institutions across the country, returned to the Garden this spring in part to re-establish a collection program.
Records of wild collected plants’ origins hold a value that extends beyond dollars. Details of when and where each collected plant was gathered are stored in the Garden’s plant records database. Those pieces of information build a story for each specimen. The stories provide guidelines for conservation scientists who may need to propagate the species should a natural habitat be temporarily lost, and for breeders who may wish to develop a new, hardy species to better endure harsher winters, for example.
Many other species of plants are preserved when their seeds are collected and placed in seed banks. However, for some, such as the sweet bay magnolias, timing the seed collection and storing them long term is difficult, so the cuttings are the best approach.
Mapping the Journey
Bunting is building a ten-year collection plan that he expects will take Garden experts to one or two national and one international location(s) each year. “I would like this new plant-collecting program to really think about filling a lot of needs at the Garden, whether it’s evaluation, breeding, plant conservation, adding to our horticulture collection, or maybe interpretation and education,” he said. Collections will take place in similar climates to the Chicago area.
In Delhaas Woods, cuttings are labeled and pressed between pieces of cardboard for transportation to a herbarium for further processing and storage.
Plants selected for collection may be representative of a different country, or they may expand the Garden’s representation of a specific species, for example. Working with other Garden scientists, graduate students, and the Morton Arboretum, he is also building in steps to ensure that species are screened in advance so that no potentially invasive species are collected.
“There are lots of parameters and variables that will evolve over time and also partnerships,” he said. The collecting trips will be done with a consortium of institutions from across the country. Results will be shared and tracked among them, and stored at the herbarium at the U.S. National Arboretum in Washington, D.C. Many will also remain long term at the Garden or other similar institutions. “We do want to fill in gaps (in the Garden’s collection), but we also want to add diversity,” said Bunting.
Sweetbay magnolia trees in a New Jersey state forest
Over the next several months, Rothleutner will work to propagate the recent sweetbay magnolia cuttings. They will then be dispersed among selected gardens, including several that together hold a full representation of magnolia species from the United States and that are coordinated by the APGA. Plants will also be cultivated at the Chicago Botanic Garden.
So many of you corpse flower fans had questions about Alice’s bloom time and scent that I thought I’d give you a timeline and extra details about Alice’s big night and the day that followed.
Over the course of 2 days, over 13,700 people came to see Alice the Amorphophallus; by the end of the weekend 20,000 people saw the bloom.
Loving the “buzz”! Did we surpass caffeine in popularity this evening? A short while after this screenshot was taken, we did.
What a day, and what a week! Alice the Amorphophallus took us all by surprise by beginning her bloom cycle late on Monday, September 28. We’d been expecting her to bloom around October 1, and had been watching for the telltale clues, just as we had with Spike in August. Alice’s two outer bracts had fallen away on the weekend, but she continued to grow.
Pampered like a movie star and protected from direct sunlight this time of year with a beach umbrella, she enjoyed a cozy, humid greenhouse. We watered frequently and monitored Alice’s internal temperature, checking several times each day with the use of a new, forward looking infrared (FLIR) camera—a thermographic camera that senses infrared radiation—since the heating of the spadix (the tall spike in the middle) over 90 degrees Fahrenheit is a sure sign that bloom has started.
Our precocious plant, however, decided to begin opening late at night! Around 11 p.m. Monday evening, it was evident that the spathe was pulling away from the spadix, and by 2:30 a.m., there was a noticeable smell—from outside the greenhouse. Alice was blooming.
Alice the Amorphophallus in full bloom, around 8 a.m. on September 29, 2015.
A thermographic image of Alice in bloom shows the spadix heating up.
Alice’s Flowering Timeline
Monday, September 28, 11 p.m. — The spathe (a frilly modified leaf) begins to pull away from the tall spadix (flower spike); Alice’s internal temperature begins to increase to help volatize the odor to attract pollinators.
Monday – Tuesday, September 28 – 29, midnight to 10 a.m. — This is the peak of the flowering period, when the strongest odor is produced. The odor is noticeable when entering the Regenstein Center and Semitropical Greenhouse. The spathe is most open during this time (to about 75 percent). The spadix temperature is at its highest point of 95 degrees Fahrenheit internally; the female flowers are receptive to pollinating at this time.
Tuesday, September 29, 8:30 a.m. — Small windows are cut open at the base of the spathe to perform the “manual pollination process,” using the pollen from Spike and donated pollen from the Denver Botanic Gardens (from a titan arum named Stinky).
Tuesday, September 29, 10 a.m. to 3 p.m. — The odor begins to dissipate; it is only noticeable within 10 feet of the plant.
Tuesday, September 29, 3 to 10 p.m. — The spathe begins to close up. The temperature of the male flowers increases to 87 degrees Fahrenheit to help ripen the male flowers to produce pollen (see photo above).
Tuesday, September 29, 11 p.m. — Pollen is collected from the male flowers to save for future pollination of the other titan arums in the Chicago Botanic Garden’s collection and to be available to donate to other botanic gardens and universities, as requested.
Wednesday, September 30, 6 a.m. to noon — There is very little odor, except within 2 feet of the bloom; the spathe is about 25 percent open.
Thursday, October 1 — The spathe continues moving closer to the spadix; there is very little odor.
Friday, October 2 — The spadix begins to soften and collapse, and the spathe withers. The plant diverts energy to continue the pollination process, as well as the development of fruit and, eventually, seeds.
Monday, October 5 — The spadix has collapsed and fructescence (the developing of fruit after pollination) begins.
Tuesday, October 6 —Alice moves back into the production greenhouses with the titan arum collection. Fruit will develop over the next several months.
Visitors online enjoyed the scene as much as those here in the greenhouse.
Asked to share my most memorable moments, I answer that they naturally revolved around the kids. So many kids had come to see Alice, many awake way past their bedtimes! One special moment stands out:
A 12-year-old girl, who’d come to see Spike four or five times (plus watched live on the webcam), came up to me and said, “I just had to come to Alice too! I’m so excited! And I couldn’t wait to meet Titan Tim! Can I get my picture with you?” My heart grew ten times larger right then and there. She was practically jumping out of her shoes, even after waiting more than two hours in line. She told me she’d just ordered a voodoo lily online (it’s a close relative of Amorphophallus titanum) and said, “I can’t wait for it to bloom, to smell it!” I knew in that moment I was speaking to a potential future horticulturist or botanist.
Late summer was a great time for a visit to Windy City Harvest’s Legends South incubator farm.
This summer, we hosted Katie Wilson, Ph.D., USDA deputy under secretary for food, nutrition, and consumer services (FNCS), who walked the entire two-acre site with us in Chicago’s Bronzeville neighborhood. Dr. Wilson marveled at all the organic greens—kale, collard, lettuce, and more—that eventually makes its way to low-income mothers whose young children are at risk for nutritional problems. Wilson mentioned that small-scale farming is close to her heart—her son helps lead operations at his college’s farm in Wisconsin.
Rosario Maldonado of Creciendo Farms, a Windy City Harvest 2013 Apprenticeship Graduate
What prompted her visit is the unique approach the site offers in leveraging two USDA programs—the Beginning Farmer and Rancher Development Program (BFRDP) and the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Windy City Harvest has partnered with Community and Economic Development Association of Cook County, Inc. (CEDA) for more than five years to distribute produce through WIC channels and is proud to now offer it as a channel for farmers. Farmers at the two-acre urban refuge grow an assortment of vegetables for WIC produce boxes, distributed to 95 families per week at various offices throughout the city from June through October.
Stacey Kimmons of Return To Life Farming, a Windy City Harvest 2014 Apprenticeship Graduate
As part of a BFRDP grant program, the businesses receive necessary infrastructure and support from the Chicago Botanic Garden to help mediate the risks involved in starting their own farming-related business. An affordable lease of ⅛-acre ready-to-farm land, irrigation, tools and equipment, a processing area, technical assistance, and a guaranteed point of sale for their produce are provided under the grant. The BFRDP also funds industry-specific, 14-week courses created by Windy City Harvest in business and entrepreneurship, aquaponic production, season extension, and edible landscaping/rooftop farming. These courses are open to farmers looking to continue their education in this ever-expanding field of opportunity. The Garden is in its third year of the BFRDP program and has incubated 11 farm businesses; two in its pilot year, three in it first full year, and currently six in 2015.
The farm businesses providing to WIC this year are Creciendo Farms, owned by Rosario Maldonado and Fernando Orozco of McKinley Park, and Return to Life Farming, owned by Stacey Kimmons of South Shore. Both farms have a deep commitment to the mission of WIC—to provide supplemental nutrition to low-income babies, young children, and pregnant and post-partum women.
The growers of Creciendo Farms, including Windy City harvest graduates Rosario Maldonado and Fernando Orozco (far right)
Fernando and Rosario both received WIC benefits themselves as children. They believe that farm-to-clinic WIC boxes serve as a great way to introduce families to fresh, local produce, while allowing farmers to serve their communities and build sustainable businesses.
Stacey chose WIC as his primary market to serve because, he said, “I wanted to make sure I helped assist them in having healthy choices of food.” When developing his business plan, he knew he wanted to farm for profit as well as support a great cause. “I have friends who have WIC, and they have nothing but positive things to say about it, and now to know that I have something to do with that positive thing, is a great feeling.”
When Ross Gerbasi and his coworkers at Threaded Films heard that the Chicago Botanic Garden’s first titan arum, Spike, might bloom in August, they immediately thought, “puppet.”
An unusual thought, unless you happen to be Ross…or his mom, Debi Gerbasi…or artist Jessica Plummer. These three started making puppets together for fun about a year ago. Naturally, the group began with puppets of themselves…then of all the guys at Threaded Films (a video/production company with a penchant for film gear).
Titan Taylor was almost as big a star as #CBGAlice.
Although Spike lost energy and never did open, Ross and his mom and Jessica kept the energy going on their titan arum puppet project. Slowly, the basement of Debi’s house turned into a creative factory, with floor-to-ceiling plastic walls around the sanders, saws, and drills. (A separate, dust-free area houses Debi’s well-furnished sewing room.)
Ross Gerbasi and TItan Taylor talked and posed with fans in the bonsai courtyard until 8 p.m.
Jessica took the creative lead for shaping the titan puppet, which is made of foam. Paper templates came first; next came foam that could be heated, bent, sanded, carved, airbrushed, and painted. The spadix (the tall structure in the center) is made of lightweight, open-cell foam…with buttons for eyes. The puppeteer’s arm goes up a sewn-on sleeve inside.
Just as the puppet, dubbed Taylor (whose name was chosen for its genderless quality), was finished, Ross and company heard that a second titan arum had sent up a flower bud at the Garden. Ross brought Taylor to our office to meet us—and we immediately “booked” it as “public puppet” for the night that the second titan, dubbed Alice the Amorphophallus, would bloom.
That turned out to be September 29, 2015, and with Ross as puppeteer, Taylor turned out to be an attraction second only to Alice herself. Children flocked to the puppet, thrilled to meet their first titan. Adults with big smiles took photos and selfies.
