Archives For Andrew Bell

The versatility of the willow in the landscape, its year-round ornamental appeal, and its adaptability to colder climates make it a staple and a highlight of the Garden’s plant collections. In fact, the Garden is committed to amassing and displaying one of the largest collections of willows in the country. This initiative was started informally more than two decades ago when Kris Jarantoski, the Garden’s executive vice president and director, began collecting willows from other institutions.

PHOTO: Willow tree at Dudley Point, at the Serpentine Bridge.

The Garden has 2.4 million plants, and specializes in the cultivation of a select few genera. These specialized collections will become collections of distinction, recognized nationally and internationally.

Willows have long been used by indigenous cultures worldwide. Ancient cultures used the willow as medicine (aspirin derives from salicylic acid—a component found in willow bark); as weaving material for baskets; and for creating shelter. These days, willows are used in furniture; as a material in cricket bats; and as an ornamental landscape plant.

PHOTO: Salix tarraconensis catkins in winter.

Shrub willows like this Salix tarraconensis are a highlight of the Garden’s specialized collections.

The willow genus (Salix) contains more than 400 species. Derived from the Celtic word sallis—sal ‘near’ and lis ‘water’—their genus name describes the ideal natural habitat of most willows. Despite a natural affinity for water, however, many members of this diverse genus are adaptable to various landscape conditions, including dry sites (once established). Most are native to the cooler regions of the Northern Hemisphere, but a few species occur naturally in the Southern Hemisphere. (Australia does not have native willow species, although willows are cultivated there.) 

Developing a world-class collection of willows is a team effort

The process of developing a specialized collection involves much more than acquiring as many difference species and varieties as possible. It also involves ongoing research on these collections by Garden staff and others. But before that is possible, it is essential the collection is authenticated—just as an art museum would do with a painting it received.

PHOTO: A group of willow twigs shows a variety of color for the winter landscape.

Willow twigs are a colorful highlight of the winter landscape. Shown here are twigs from four varieties in the collection.

Willows are a complex and difficult group to accurately identify, and the Garden is currently in the process of verifying its holdings—a process that we believe will take nearly three years!

Emily Russell, assistant curator of woody plants, and Frank Balestri, research assistant at the Garden, work with our collaborators Michael Dodge, a willow enthusiast and owner of Vermont Willow Nursery, and Irina Belyaeva, Ph.D., taxonomist at the Royal Botanic Gardens, Kew.

Russell and Balestri and their teams of photo documentation and herbarium voucher staff and volunteers have devoted countless hours to the willow effort. Russell accompanies Dodge as he surveys the Garden’s collections during visits, and records new information as it becomes available. Balestri’s primary role has been to collect herbarium vouchers prepared by volunteers that will be shipped to Dr. Belyaeva early next year. As we near the end of year two, we are still very busy in these winter months as we continue to collect digital images and herbarium vouchers!  

PHOTO: Emily Russell and Michael Dodge looking at alpine Salix in the rock garden.

Emily Russell and Michael Dodge look at alpine Salix in the rock garden.

PHOTO: Frank Balestri examines a Salix herbarium voucher.

Frank Balestri examines a Salix herbarium voucher

While we continue this project over the coming months, we encourage you to visit the Garden and explore our Salix collection. Winter is a great time to explore the wonderful world of willows!

Learn about the ornamental value of Salix, the characteristics of shrub species, and their beauty in the winter landscape in the winter issue of Keep Growing.

©2015 Chicago Botanic Garden and

Trees for 2050

A study of suitable trees for a warming midwestern climate

Andrew Bell —  September 4, 2013 — 10 Comments

A living museum presents special challenges to its curators.

At the Chicago Botanic Garden, we not only acquire and display our collections, but we must also keep them alive and healthy. As curator of the Garden’s collection of woody plants, I’m responsible for the welfare of more than 13,000 trees. Disease, infestations, and extreme weather events are the kinds of things that keep me awake at night.

If you have recently lost a tree to emerald ash borer, you may wish to view our short list of ash replacement selections. Our full list of suggested trees for adaptive planting is linked below.

As you may know, the Garden is undertaking a ten-year plan to remove about 400 trees due to the emerald ash borer. It’s up to me to suggest suitable replacements to continue our tree legacy. To do so, I first needed to know which of the trees now growing in the Garden would continue to thrive in a warming urban environment. Thanks to a $120,000 research grant from the U.S. Institute of Museum and Library Services, we’ve been able to undertake an adaptive planting study to identify which trees will continue to thrive in Chicago’s urban forests under worst-case carbon-emissions scenarios.

Climate-change modeling indicates that some trees—those currently growing at the northern edge of their hardiness—will actually do a little bit better in slightly warmer conditions around 2020, but by 2050, ten of the 50 trees under study—20 percent—will no longer find the metropolitan area a welcoming habitat. The real concern sets in when we look at the data for 2080, which projects that only 11 of the initial trees would continue to do well in Chicago and the upper Midwest.

The trees growing along our city streets, parks, residences, and public gardens enhance the quality of metropolitan living and also play an important role in reducing greenhouse gas emissions. The cooling summer leaf canopy reduces our energy needs, and the trees themselves store significant amounts of carbon.

Our adaptive planting study suggests two key calls to action: drastically reducing carbon emission to slow climate change and help protect existing trees, and carefully selecting the trees we plant for future generations. To help both public officials and private property owners in their tree selections, the Garden has created an Adaptive Planting page on our website. There you’ll find information on a selection of 60 suitable trees for 2050.

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This project is made possible in part by a grant from the Institute of Museum and Library Services (IC-01-11-0145-11)
©2013 Chicago Botanic Garden and