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It might be fall, but the last weeks of September felt like summer, and that’s going to change how long trees will show off their seasonal colors.

On the official first day of fall, temperatures in the Chicago area reached well into the 90s. Heat and the recent lack of rainfall means trees are going into survival mode to conserve water, which means that mid-October’s typical fall colors will be affected. 

Deciduous trees, explains Boyce Tankersley, director of living plant documentation, respond to environmental conditions when preparing to go dormant for the winter. Just like animals that hibernate, trees slow their processes down in order to conserve energy. What we can see of this process can be beautiful: leaves change from green to vibrant reds, oranges and yellows. Then trees will drop their leaves and wait out the winter.

In a regular year, trees aren’t in a rush to go dormant. The process that we see takes several weeks. The production of chlorophyll, which produces the green color in leaves, fades away, unmasking the beautiful colors we associate with autumn. As the season progresses, the leaves will eventually drop. In Chicago, our trees usually reach peak color in the first two weeks of October, and aren’t usually bare until late October or early November.

But this isn’t a regular year. The heat we’ve been feeling lately is a factor.

Fall leaf color

Expect color, but this year’s display will be shorter than usual.

“The higher the temperature, the faster the processes go,” Tankersley said. And this month’s drought is why we’re also seeing leaves dropping only a few days into fall. Local rain gauges have been virtually dry, with less than 2 inches recorded in the month of September.

“Trees don’t have minds, but they do respond to environmental clues. If there’s been little rain, they will drop their leaves early in order to conserve water and get through the rest of fall and winter,” he said.

If you’re a fan of getting family portraits done with a backdrop of colorful foliage, Tankersley suggests getting those done sooner rather than later.

“This year, we’re going to have to be a little bit more proactive about getting out there and getting photos as the trees come into color. They’re just not going to hold.”


©2017 Chicago Botanic Garden and my.chicagobotanic.org

The Supreme Court has been asked to opine on many critical issues of its time. These cases have had profound impacts on our society and even the progression of democracy. But perhaps the most important Supreme Court case of all time—at least if you are a hard-core plant geek—was Nix v. Hedden, 1893, in which the Court ruled that the tomato is, for the purposes of taxation, a vegetable.

In the spring of 1886, the Nix family made their living importing tomatoes into New York City from the West Indies. Based on the Tariff Act of 1883, the New York Port tax collector assessed a duty on these imported tomatoes. The Tariff Act required a 10 percent duty on “vegetables in their natural state…” But, the Nix family contended, a tomato is a fruit, botanically speaking, and should not be taxed as a vegetable. The New York tax collector was unmoved by this argument and forced the family to pay the tax, though he did record that the tax was paid under protest.

Blindfolded Lady Justice weighs a tomatoPeople were just as reluctant to pay taxes in 1886 as they are today, and as any good botanist of the nineteenth or twenty-first centuries would tell you, the tomato is indeed a fruit. Its tissues derive from the reproductive organs of the plant (and contain seeds), making it a textbook fruit. It’s not even botanically confusing like the oddball strawberry, which is technically a swollen receptacle that holds fruits (the little black achenes on the strawberry’s surface). A tomato is about as clearly a fruit as there is, botanically speaking.

Yet, in common language, we tend to think of fruits as sweet and vegetables as savory. Or perhaps more basically, fruits are for dessert and vegetable go with the main course.

When the tax assessor for the New York Harbor used the common language meaning of tomato as the rationale to levy a tax, in opposition to the botanical definition used by the Nix family, I doubt he knew he was opening a legal can of worms that would end up in the Supreme Court.

The Nix family sued the tax collector. The case was heard by the Circuit Court of the Southern District of New York. The case primarily consisted of entering into testimony the dictionary definitions of fruit and vegetable. The court sided with the tax collector, and the Nixes appealed. Somewhat amazingly, the Supreme Court agreed to hear the case, and registered judgement on May 10, 1893.

By this point, the case was not so much about whether or not a tomato is botanically a fruit. In fact, in his opinion, Justice Horace Gray of Massachusetts freely admitted that “botanically speaking, tomatoes are the fruit of the vine…” But he made a distinction between the common language of the people and the botanical definition. Specifically, he noted that tomatoes are “usually served at dinner in, with, or after the soup, fish, or meats which constitute the principle part of the repast, and not, like fruits generally, as dessert.” He even cited from Supreme Court precedent. In 1889, Robertson v. Salomon, the Court held that, again for tax purposes, white beans (which definitely are seeds) should be taxed as vegetables, and not classified as seeds, which were exempted from taxation. Justice Joseph P. Bradley of New Jersey wrote of white beans, “We do not see why they should be classified as seeds, any more than walnuts should be so classified. Both are seeds, in the language of botany or natural history, but not in commerce nor in common parlance.”

Grape tomatoesRead more about cultivating tomatoes in our Tomato Talk series on Facebook (#CBGTomatoTalk) and at chicagobotanic.org

The Supreme Court unequivocally stated in Robertson v. Salomon and then reaffirmed in Nix v. Hedden that a technical definition should not necessarily stand in the way of an ordinary or common meaning. According to the high court, tomatoes and white beans are not fruit and seeds, respectively. They can, and should, be taxed as vegetables.

These cases are important to legal history in delineating the differences between technical and common usages of words under legal dispute. But what should a botanist learn from this legal tomato obscurity?

Principally, science and the law are quite different systems. You may conflate them at your own peril. Scientific logic is not always compatible or supported by legal doctrine. Under the law, up can be down, black can be white, and tomatoes aren’t fruits.

And above all, it’s very hard to avoid paying taxes.


Dr. Ari Novy

Dr. Ari Novy

Guest blogger Ari Novy, Ph.D., is chief scientist at the Leichtag Foundation in Encinitas, California, and a research collaborator at the National Museum of Natural History in Washington, D.C. He’s interested in pretty much everything about plants, including obscure legal minutiae.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

Last month, torrential rains fell over much of our region, particularly in Lake and McHenry counties, as well as southeastern Wisconsin. Here at the Chicago Botanic Garden, high water levels in the Skokie River forced us to close on July 13 and 14—the first time in the Garden’s history that we’ve been closed to visitors for two consecutive days. 

So what exactly happened that required us to close? And how did the flooding affect our plants? 

Flooding at the visitor entrance’s main intersection

Flooding at the visitor entrance’s main intersection

Skokie River watershed map

The Skokie River watershed, highlighted in blue. (Click here for larger view.)

The Garden is situated in the “watershed” of the Skokie River that extends north to Waukegan. A portion of the rain that falls in this upstream, 20-square-mile watershed eventually finds its way to the Skokie River. During the early morning of July 12, between 3 and 5 inches of rain fell in that watershed area over a matter of hours, resulting in a rapid rise in the Skokie River as it flows around the west side of the Garden. In fact, the rainfall was so severe that portions of the village of Lake Bluff (located in our watershed) experienced rainfall intensity and quantity that is predicted to occur with a frequency of only about once every 140 years.

Prior to the Garden’s creation, the Skokie River meandered through the middle of our property. As the Garden began to take shape in the late 1960s, heavy construction equipment excavated our lakes (some exceed 16 feet deep), and those soils were then used to create the islands and display gardens that you enjoy today.

At the same time, the Skokie River was moved into a defined channel on the west side of our property near the highway, and two dams were installed at the north and south ends of our lake system to isolate it from the river except during high flows (see graphic). These dams were installed to help protect communities downstream of the Garden from flooding: if levels in the Skokie River rise high enough, river water flows over the north dam into the Garden lakes and we’ll temporarily store over 100 million gallons of floodwater. After the river’s flood peak has passed, we slowly release that water out of the Garden’s lakes and back into the Skokie River.

Map of the lakes and dams in the Chicago Botanic Garden.

Map of the lakes and dams in the Chicago Botanic Garden. (Click here for a larger view.)

Last month’s flooding at the Garden was dramatic. Our lake levels rose more than 5.5 feet above normal and were on par with the highest we’ve ever encountered. At one point early in the flood, an intersection along the Garden’s visitor entrance was submerged under more than 30 inches of water—thereby necessitating our closure.

The image below shows one of our service roads during normal water levels as it crosses a narrow point in our lake system. Compare that image to the video, taken at the peak of the floodwater inflow to the Garden, showing swift and powerful water flowing through this area. 

About three days after the heavy rains fell, the flood peak had passed, and the Garden was able to begin releasing lake water back into the Skokie River via a 10,000 gallon-per-minute pump near the south dam. Nine days later, all 100 million gallons of floodwater had been removed and our lake levels were back to normal.

The Rose Garden causeway August 16, 2017

One of the Garden’s service roads on August 16, 2017; and below, on July 13, 2017

The images below illustrate the extent of the high water levels at the Garden. Remember, at their peak, the lake levels were more than 5.5 feet above normal.

The Serpentine Bridge on July 13, 2017

The Serpentine Bridge on July 13, 2017

The Serpentine Bridge on August 22, 2017

The Serpentine Bridge on August 22, 2017

The lower walkway pergola in the Bulb Garden on July 13, 2017

The lower walkway pergola in the Graham Bulb Garden on July 13, 2017

The lower walkway pergola in the Bulb Garden on August 16, 2017

The lower walkway pergola in the Bulb Garden on August 16, 2017

Because the Garden was intentionally designed from the very beginning to accept and temporarily store floodwater from the Skokie River, we’ve experienced few long-term impacts from the recent flood. None of our buildings took on any water. Most of the vegetation near the lakeshore that went underwater survived. There was some damage to plants in the Garden—a few inundation-sensitive shrubs and herbaceous plants, as well as some turf were affected (particularly along the water’s edge of the Malott Japanese Garden). Some were pruned and others may need to be replaced with more water-tolerant taxa. Importantly, more than 500,000 native shoreline plants that we’ve installed along the Garden’s lakeshore withstood being underwater for up to nine days without impact. These plants will continue their important “engineering function” to stabilize our fragile shoreline soils and keep the slopes from eroding into the lake.

The recent heavy rainfall and flooding were of historic proportions and caused devastation to many communities in our region. Looking forward, residents can take steps to help lessen flooding: for example, installing a rain garden on your property can help reduce flooding, particularly for small- and modest-sized storm events; click here for more information. Regional solutions for stormwater management can be particularly beneficial for larger rainfall events. Countywide stormwater management agencies in our region work to implement flood control programs and help homeowners who have been affected by flooding. For more information about these agencies and the programs they offer, in Cook County, contact the Metropolitan Water Reclamation District; in Lake County, contact the Lake County Stormwater Management Commission.

And so while the recent flooding may have left a bit of soil residue on some leaves of plants located nearest the lakeshore, rest assured that all is quite well here at the Garden. In fact, the frequent rains this summer have contributed to luxuriant growth and some amazing blooms, and we look forward to a continued explosion of color as summer progresses into fall.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

A gall, tumor, or burl is an abnormal growth on the leaves, stems, roots, buds, twigs, or crown of a plant. In most cases, the gall is unsightly but not damaging. In small plants, the vascular flow of water and food can be restricted, causing poor growth and making the plant more susceptible to other stresses. A large tree can be weakened by an infection over many years. Nematodes, mites, and insects cause 95 percent of galls. Bacteria and fungi cause the remaining five percent. In most cases, the gall-making organism can be identified by observing the structure of the gall and the species of the host plant.

Galls on a Flower

Galls on Rudbeckia laciniata ‘Herbstsonne’

Fungal galls are spread by ascospores in wind and water and can be found on many common trees including oak, maple, and common privet. Black knot affects many species of the genus Prunus—particularly cherries and plums.

Crown gall is a common problem caused by bacteria. The disease is spread by infested soil, transplants, or contaminated tools. The bacteria enters the plant through wounds caused by cultivation, pruning, or insects. Easy prevention methods are to plant only healthy stock (no suspicious bumps), to clean pruners between use on each plant with alcohol or a 10 percent bleach/water solution, and to take care not to injure plant stems. The bacteria stays active in the soil even after removal of infected plants, so place new, healthy stock elsewhere. Remove and destroy all infected plants. Galls caused by bacterial and fungus are more prevalent during wet years.

A gall can form in response to toxins injected during insect feeding or egg laying, or around a feeding larva. The hackberry leaf gall is caused by psyllids, which are tiny winged insects. Galls formed by insects usually do not affect the overall health of the tree unless they experience early defoliation over the course of many years. Parasites are an important control of this pest. Many oak galls are caused by gall flies and generally are not detrimental. A severe twig infection can, however, cause severe injury and even death. Spruce galls are often caused by several species of an aphid-like insect. If only a few galls are present, they can be cut off and destroyed before the insects emerge in midsummer.

Galls on a Flower
Galls on a Flower

 

Leaf galls on maple trees form because of feeding mites. Eriophyid mites produce a gall that resembles a felt patch and may occur on the upper or lower side of the leaf. The overall health of the tree should not be seriously affected.

Nematode feeding activity can injure roots and allow gall-forming bacteria into the plant. Nematodes can also form galls on carrots, camellia, fig, gardenia, okra, potato, roses, sweet potato, and tomato. Plants can be stunted, yellow, and wilted due to restrictions on the uptake of water and nutrients. Individual nematodes are invisible to the naked eye, but egg masses can be seen as pearly objects.  Roots can appear scabby, pimpled, rough, and have knots. Two important prevention methods are to rotate with nematode-resistant crops and to maintain rich organic soil.

Please contact Plant Information Service at (847) 835-0972 or at plantinfo@chicagobotanic.org for additional information.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

We dreamed green, from the moment we started planning the Learning Center on the Regenstein Learning Campus—in every solar panel we placed, in every window we installed, in every cleaning product we used. Recently, the hard work brought us national recognition.

The Chicago Botanic Garden is pleased that the U.S. Green Building Council has awarded the top rating of Platinum LEED (Leadership in Energy and Environmental Design) to the Learning Center, which opened in September 2016. The designation means that the Garden is recognized as a leader in the green building movement. Of 51,875 projects in the United States that has earned LEED status since 2004, only 10.7 percent have been awarded platinum recognition.

Natural daylight from clerestory windows illuminates the building's main hallway.

Natural daylight from clerestory windows illuminates the Learning Center’s main hallway.

Sustainability Features

People of all ages and abilities connect with the natural world in the programs, classes, and events through the Joseph Regenstein, Jr. School of the Chicago Botanic Garden, based at the Learning Center. In every single decision we made before opening the Center’s doors, we applied the same sustainability standards that we use for our gardens: How do we save water and energy? What is the best way to reduce our environmental footprint?

Solar panels (like these on the Children's Growing Garden next door) supply 16 percent of the Regenstein Learning Center's electricity.

Solar panels (like these on the Grunsfeld Children’s Growing Garden next door) supply 16 percent of the  Learning Center’s electricity.

Here are some of the ways we did so, with the help of architects Booth Hansen & Associates and the Rocky Mountain Institute, which provided sustainability counsel. The Learning Center uses the following:

  • A rainwater capture and storage system (the rainwater is used to water the Grunsfeld Children’s Growing Garden)
  • 83 solar panels, which generate 16 percent of the building’s electricity
  • Environmentally friendly cleaning products, and paints, adhesives, and sealings with low amounts of chemicals that could harm indoor air quality 
  • 90 percent natural daylight
  • Special windows to deter bird collisions

Even outside the Learning Center, we made sure to think local and sustainable in the Nature Play Garden, with climbing boulders from Wisconsin and as many native plants as possible—not as part of the LEED certification, but as part of our environmental ethos.

“We are an organization that cares deeply about conservation and sustainability. When it comes to our buildings, we embrace energy-efficient construction practices that mitigate environmental impact,” said Jean M. Franczyk, the Garden’s president and CEO.


©2017 Chicago Botanic Garden and my.chicagobotanic.org