Archives For March 2017

The number of women in science is pretty dismal. Despite earning about half the doctorates in science, only 21 percent of full science professors in the United States are women,* but I feel very fortunate to work at an institution committed to inclusiveness and diversity. At the Chicago Botanic Garden, 25 of our 47 scientific staff are women; our graduate student body is 61 percent female. 

Still, implicit gender biases persist in science, resulting in fewer women in top positions, along with women earning less pay, winning fewer grants, and publishing fewer papers. This comes at a time when we are faced with numerous grand challenges in science and need a diversity of approaches to tackle those challenges.

In the Chicago Botanic Garden’s science program, we are conducting research on how human activities are affecting plants through climate change, habitat fragmentation, introduction of invasive species, pollinator loss, pollution, and more. These threats to plants are unlikely to diminish in the foreseeable future, and we are finding ways to conserve plants in changing and challenging environments. We are working hard to protect the plants and plant communities upon which we all depend. We are also working hard to create a pipeline into science for all—especially traditionally under-represented groups—through our Science Career Continuum, because diversity of plants and diversity of scientists are both good things.

Krissa Skogen studying hawkmoth pollination with Victoria Luizzi (Amherst College Student, NSF REU Student, Summer 2016), Emily Lewis (research assistant), Andrea Gruver (research assistant), Tania Jogesh (postdoc), and Kat Andrews (PBC M.S. student).

Left to right: Krissa Skogen, Ph.D., is studying hawkmoth pollination with Victoria Luizzi (Amherst College Student, NSF REU Student, Summer 2016), Emily Lewis (research assistant), Andrea Gruver (research assistant), Tania Jogesh (postdoc), and Kat Andrews (PBC M.S. student). Dr. Skogen is a conservation scientist and manager of the Conservation and Land Management Internship Program.

Meet some of our women scientists:

Lauren Umek studies how invasive species change plant communities and soil properties in the Chicago region and how this can improve restoration methods.

Lauren Umek studies how invasive species change plant communities and soil properties in the Chicago region and how this can improve restoration methods.

Nyree Zerega studies evolution/genomics in underutilized tropical fruit trees and their wild relatives to promote and conserve food diversity.

Nyree Zerega studies evolution/genomics in underutilized tropical fruit trees and their wild relatives to promote and conserve food diversity.

Botanist, seed conservationist and geographer Emily Yates has conserved thousands of seeds to protect the native tallgrass prairie ecosystem of the American Midwest.

Botanist, seed conservationist, and geographer Emily Yates has conserved thousands of seeds to protect the native tallgrass prairie ecosystem of the Midwest.

Ph.D. student Colby Witherup uses computers to study plant DNA, looking for signs of evolution in genes that control sexual reproduction.

Ph.D. candidate Colby Witherup studies plant DNA, looking for signs of evolution in genes that control sexual reproduction.

Evelyn Williams Ph.D. (left, with Adrienne Basey) traveled to Guadalupe Nation Park in Texas to study the shrub Burgess' Scalebroom.

Evelyn Williams, Ph.D., (left, with Adrienne Basey) traveled to Guadalupe Nation Park in Texas to study the shrub Burgess’ scalebroom.

Amy Waananen studies populations of Echinacea angustifolia in Western Minnesota as a research assistant for The Echinacea Project, a long-term ecological study that began in 1995.

Amy Waananen studies populations of purple coneflower (Echinacea angustifolia) in western Minnesota as a research assistant for The Echinacea Project, a long-term ecological study that began in 1995.

Mary Patterson studies restoration, invasive species, and fire ecology with a focus in the Western United States.

Mary Patterson studies restoration, invasive species, and fire ecology with a focus in the Western United States.

Joan O'Shaughnessy manages the Dixon Prairie at the Garden.

Joan O’Shaughnessy manages the Dixon Prairie at the Garden.

Kelly Ksiazek-Mikenas studies how green roofs can provide habitat for native plant species.

Kelly Ksiazek-Mikenas studies how green roofs can provide habitat for native plant species.

Andrea Kramer, Ph.D., conducts research on native plants to support ecological restoration that sustains people, wildlife, and the planet.

Andrea Kramer, Ph.D., conducts research on native plants to support ecological restoration that sustains people, wildlife, and the planet.

Rachel Goad is a botanist with a background in restoration ecology and a keen interest in native plant conservation.

Rachel Goad (far right) is a botanist with a background in restoration ecology and a keen interest in native plant conservation.

Louise Egerton-Warburton's work examines soil fungal diversity and functioning and its role in ecosystem processes.

Louise Egerton-Warburton, Ph.D., does work examining soil fungal diversity and functioning and its role in ecosystem processes.

Research assistant Susan Deans uses neutral genetic markers to examine how well gardens and conservation collections capture the remaining wild genetic diversity of threatened Hawaiian plant species.

Research assistant Susan Deans uses neutral genetic markers to examine how well gardens and conservation collections capture the remaining wild genetic diversity of threatened Hawaiian plant species.

Ph. D. student Becky Barak studies plant diversity in restored tallgrass prairies.

Ph.D. candidate Becky Barak studies plant diversity in restored tallgrass prairies.

Kay Havens studies rare plant conservation, restoration, pollination and plant responses to climate change.

Kay Havens, Ph.D., studies rare plant conservation, restoration, pollination and plant responses to climate change.


*From Inequality quantified: Mind the gender gap, by Helen Shan, 06 March 2013, nature.com

©2017 Chicago Botanic Garden and my.chicagobotanic.org

In recent years, the plight of pollinators has gotten a lot of press, and rightly so.

I spoke with the editorial board of the Chicago Tribune when they were investigating the well-intentioned distribution by General Mills of “one size fits all” wildflower seed packets to combat the declining populations of bees and other pollinators. 

The decline of pollinator populations is well documented around the globe. Much attention has focused on honeybees, which are extremely important agricultural pollinators, but many of our native bees are vastly more imperiled. For example, the rusty patched bumblebee, native to the Upper Midwest, was just listed this month by the U.S. Fish and Wildlife Service as endangered.

A rusty-patched bumblebee on Culver’s root in the UW–Madison Arboretum. Photo by Susan Day, UW-Madison Arboretum.

A rusty-patched bumblebee working on Culver’s root in the University of Wisconsin–Madison arboretum. Photo by Susan Day, UW-Madison Arboretum.

Many people are concerned about these losses and asking what they can do to help support bees, butterflies, and other pollinators. For a start, it’s more beneficial to pollinators to plant species that are native to your region, and perennial. Here are five more pollinator-friendly actions that everyone can take.

  1. Provide resources: For pollinators, this means flowering plants with pollen and/or nectar. Diversity is key, as flowers of different colors and shapes will attract different pollinators. Be sure to provide resources across the entire growing season, so include species that bloom in spring, summer, and fall. Regional native plants are the species our local pollinators evolved with, so they recognize and use them…and you don’t have to worry that they will become invasive!
  2. Provide host plants: The larvae of many butterflies and moths have particular species that they need to eat to develop, as monarchs need milkweed. Providing host plants will ensure that the next generation of butterflies can mature. Just be willing to accept hungry caterpillars eating those plants.
  3. Provide nesting sites: Many insects like to nest in bare ground, hollow stems, or leaf litter. Allowing your yard to be a little less tidy can benefit insects. Many attractive bee houses are available for sale, and do-it-yourself instructions can be found on the web.
  4. Avoid pesticides: Pesticides are designed to kill insects, but sometimes they also kill pollinators unintentionally. Systemic pesticides can persist in plants for long periods of time and are present in all parts of the plant, including nectar and pollen. So if you choose plants for a pollinator garden, make sure they haven’t been treated with systemic pesticides. If possible, make your entire yard pesticide-free.
  5. Learn more about pollinators: There are some great resources on the web—including those created by the Pollinator Partnership and the Xerces Society—that can help you do even more for pollinators.

Help for pollinators begins in your own backyard. These native plants below are recommended to bring back pollinator populations. (Don’t overlook trees—native maples and willows can provide critical resources early in the season.)

Beebalm or bergamot (Monarda fistulosa)

Beebalm, or bergamot (Monarda fistulosa)

New England aster (Symphyotrichum novae-angliae)

New England aster (Symphyotrichum novae-angliae)

Stiff goldenrod (Oligoneuron rigidum)

Stiff goldenrod (Oligoneuron rigidum)

Prairie blazing star (Liatris spicata)

Prairie blazing star (Liatris spicata)

American pussy willow (Salix discolor)

American pussy willow (Salix discolor)

Purple coneflower (Echinacea purpurea)

Purple coneflower (Echinacea purpurea)


Read more about the science behind this important topic in the Natural Areas Journal article, The Importance of Phenological Diversity in Seed Mixes for Pollinator Restoration by Kayri Havens and Pati Vitt, Chicago Botanic Garden.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

Update 4/13/2017: The University of Illinois Extension Program has created a fact sheet for identification of boxwood blight. Download the factsheet here.


Late last year, a colleague asked me to have a look at a boxwood planting at a residence in Winnetka. He indicated that it was looking poor and dropping some leaves. I have seen boxwood with various problems, so I was already guessing what it could be.

Upon arrival, I noted bare sections that had dropped leaves, but also noted strange black streaks on the stems. I ran a moisture chamber test that revealed pink-colored mycelial growth on the leaves, an indication of Volutella blight (a common disease on boxwood that I have seen many times before). More alarmingly, I saw white mycelial growth on the stems that could be signs of boxwood blight—a serious disease of boxwood that has never been found in Illinois. With this in mind, I expressed a sample to the University of Illinois Plant Clinic for diagnosis. About two weeks later, I received a call from the Illinois Department of Agriculture (IDOA) regarding the sample, and yes…it was positive for boxwood blight.

Boxwood blight photo by Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org

Boxwood blight photo by Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org

Since then, boxwood blight has been found in two other locations in Illinois. All have been traced to nursery stock that came from a source that was not in Illinois; this is good. The IDOA is hopeful that these are isolated incidents that can be contained. Later this month, the IDOA will likely issue a “nuisance declaration” for boxwood blight; this will allow them the authority to mandate proper removal of infected boxwood in an effort to stop any spread.

Boxwood blight photo by David L. Clement, University of Maryland, bugwood.org

Boxwood blight photo by David L. Clement, University of Maryland, Bugwood.org

Boxwood blight photo by Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org

Boxwood blight photo by Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org

Boxwood blight was first discovered in the United States in 2011. Currently, it has been identified in 18 states, primarily in the east. It is being managed at a state level, with various states having different regulations. Some states require nurseries to practice boxwood blight cleanliness programs to ensure the plants they sell are disease free. Here at the Chicago Botanic Garden, we are developing protocol to monitor incoming plants and to monitor our existing collection.

Now that boxwood blight has been found in Illinois, and because boxwood is such a common landscape planting, I feel we should all have a good understanding of this new pathogen. There is no need to panic, but if you have boxwoods, you should monitor them this growing season. I will briefly review boxwood blight for you, but you can find many great fact sheets online by searching for “boxwood blight.” One fact sheet that I found very comprehensive was titled, “Best Management Practices for Boxwood Blight,” from the Virginia Cooperative Extension. Also, the Garden’s Plant Information Service can help you with questions about boxwood blight, but we ask that you do not bring in samples. Call (847) 835-0972, or email plantinfo@chicagobotanic.org.

Photo by Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org

Boxwood blight photo by Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org

Boxwood blight (Calonectria pseudonaviculata) is a serious fungal disease that primarily affects boxwood (Buxus spp.), but can also hit Japanese pachysandra (Pachysandra terminalis), and sweetbox (Sarcococca spp.). Boxwood blight causes leaf spots, stem cankers, and defoliation. The pathogen itself does not kill the plant, but weakens it to a poor state of health, allowing secondary pathogens to kill the plant. The primary means of spread is by movement of contaminated plants, but it can also be spread via pruning tools, clothing, equipment, and contaminated soil/organic matter. The pathogen can survive in soil and organic matter for years and is easily disseminated by water movement.

Management suggestions:

  • Monitor your boxwood (at least one a month). Look for the following:
    • Leaf spots—light or dark brown circular lesions, often with a yellow halo.
    • Stem cankers—dark brown to black cankers on the stem, diamond shaped or as vertical streaks.
    • Defoliation—sections of the plant dropping leaves.
    • If you feel you have found boxwood blight, you should contact the IDA or send a sample to the University of Illinois Plant Clinic for diagnosis. Please do not bring suspect samples to the Garden.
  • Inspect purchased plants carefully before bringing them home.
  • Home care:
    • Plant in locations with good air circulation.
    • Prune to increase air circulation.
    • Sanitize pruning equipment before going from one plant to another. Lysol disinfectant works well.
    • Water at a time of day that the plants will dry quickly.
    • Avoid overhead watering if possible.
    • If desired for a hedge or mass planting, it is best to plant loosely and allow them to grow into each other; do not plant tightly.

If we learn of anything new with boxwood blight in Illinois, we will do a follow-up blog. For now don’t panic; just monitor, monitor, monitor.


The Garden is a member of the Sentinel Plant Network, a group that unites botanic gardens in monitoring and providing education on exotic plant pests and pathogens, and works in partnership with the National Plant Diagnostic Network (NPDN).

If you are a plant and bug person like me, please consider becoming a NPDN First Detector and help be on the lookout for these exotic plant pests and pathogens. The NPDN offers an online training course to become a First Detector at firstdetector.org. It’s free, and upon completion, you even get a printable certificate!


©2017 Chicago Botanic Garden and my.chicagobotanic.org

While we are in the midst of the exquisite Orchid Show, the Garden is already planning a summer of Brazil in the Garden, highlighting the influence of Brazil on gardens, arts and culture, and conservation. This seems like a great opportunity to publicize some Brazilian orchids that have been among my favorites all the years I have grown orchids at home.

PHOTO: Cattleya coccinea and hybrids from the Wisconsin Orchid Society Show on February 26, 2017.

Cattleya orchid (Cattleya coccinea) and hybrids from the Wisconsin Orchid Society Show on February 26, 2017—my plants!

First, a few facts.

Brazil has one of the highest diversities of orchid species of any country in the world, with more than 2,500 species reported, and no doubt many more undescribed species from the botanically unexplored interior. If you enjoy orchids at all, you have already seen Brazilian orchid species or the hybrids derived from them. Just a few of the well-known orchids that are indigenous to Brazil are many of the Cattleya species as well as many of the former Sophronitis and Laelia species now included in Cattleya; also species from Epidendrum, Maxillaria, Miltonia, Oncidium, Phragmipedium, Stanhopea, and others. The national flower of Brazil—Cattleya purpurata (formerly Laelia purpurata)—is also an orchid.

The native orchids of Brazil are often epiphytes growing on trees and shrubs, but can also be terrestrial, and even lithophytes (growing on rocks). They can be found from hot and humid lowland tropical areas, to seasonally dry and cooler interior regions, to high elevations in cloud forests. The care of Brazilian orchids and their hybrids in cultivation is as varied as the number of species and their habitats, but where they naturally occur provides clues for how to grow them in cultivation. Luckily, the vast orchid literature available often includes information on their culture. 

Which brings us to Cattleya coccinea, the compact—yet brilliant—jewel of my orchid collection.

Cattleya coccinea

PHOTO: Cattleya coccinea

Cattleya coccinea

Formerly recognized and still more commonly referred to as Sophronitis coccinea, C. coccinea is one of perhaps six to nine species and as many varietal color forms included in the former genus Sophronitis. While all the species are delightful in their own right, C. coccinea is the best known. It has long been grown, line-bred (crossed within the species) to improve it, converted to tetraploids (double the typical number of chromosomes) to produce plants with even larger flowers, and especially used in breeding to impart large bold flowers on compact plants. Literally thousands of orchid hybrids have C. coccinea lurking in their background. But I prefer the species or hybrids that are at least 25 to 50 percent C. coccinea, and so still bear a strong resemblance to the species.

Cattleya coccinea is a diminutive grower, with cylindrical pseudobulbs less than 1 inch tall, each topped by a solitary leaf all of 2 to 3 inches in height. A clue you are giving your C. coccinea sufficient light is when each leaf has a red stripe on top of the mid-vein. Under my growing conditions, C. coccinea can produce flowers any time from November to May, and will often bloom two or three times in succession. One to two flowers are produced per new pseudobulb. The flowers can be from 1 to nearly 3 inches wide in the best forms, dwarfing the plant. Flowers are a brilliant red to orange-red with some yellow and/or orange in the small lip. Look for forms with flat flowers and broad overlapping petals. They are always a draw in bloom. Related species are less frequently encountered. Cattleya cernua (Sophronitis cernua) has much smaller flowers but produces more per growth, is very vigorous, and tolerates warmer summer temperatures. There are yellow-flowered versions of both C. coccinea and C. cernua, but these are very hard to find and are priced accordingly. Cattleya wittigiana is similar to C. coccinea but with attractive rosy-pink flowers instead. It has been put to good use in breeding. Confusingly, C. wittigiana is also known as C. rosea, Sophronitis wittigiana, and Sophrontis rosea. The other species are rarely seen.

PHOTO: Cattleya-dichroma-(formerly-Sophronitis-bicolor)

Cattleya dichroma (formerly Sophronitis bicolor)

Tips on cultivating Cattleya coccinea

Culture of Cattleya orchids can be demanding. In its relatively high-elevation native habitats in Brazil, C. coccinea is an epiphyte on trees and shrubs, receiving strong light to full sun, high humidity, strong air movement, and cool temperatures. Try to duplicate these conditions in cultivation. I grow mine mostly in New Zealand sphagnum moss in small clay pots, replacing the moss every winter. They can also be mounted on small pieces of cork bark with a bit of sphagnum moss to help retain moisture. Do not repot them in the summer. Cool temperatures are optimal, with nights as low as 45 degrees Fahrenheit (I aim for around 52-degree nights) and day temperatures no higher than 86 degrees in the summer. Constant high relative humidity and excellent air movement are essential. Never allow the roots to dry out for too many days. These are also sensitive to hard water. If you can, water with rainwater if your water quality is suspect. I fertilize mine weekly when in growth with a variety of fertilizers, alternating 15-5-15 Cal Mag with an occasional 30-10-10 acid feed. (Other growers rarely fertilize at all. It is a matter of personal preference and cultural conditions.)

The former Sophronitis species are not for beginning orchid growers. But with attention to their cultural preferences, they can thrive in the hands of experienced orchid growers. I adore them for their interesting foliage, dwarf habits, and their vibrant and glowing flowers that dwarf the plants. Look for their easier-to-grow hybrids as well.

PHOTO: Cattleya Wild Fire, a hybrid of Cattleya coccinea and Cattleya wittigiana.

Cattleya ‘Wild Fire’, a hybrid of Cattleya coccinea and Cattleya wittigiana


The Chicago Botanic Garden does not have any of the former Sophronitis species in its collections (I’ll work on that), but there is a good chance that at least some of the species, or hybrids from them, will be on display at the Illinois Orchid Society Spring Show, held March 11 and 12 here at the Garden. The IOS show, which is layered on top of the Garden’s Orchid Show, will include numerous exhibits, judging of the best plants, multiple vendors with plants and growing supplies for sale, an information desk, and a repotting station. Also, look for Brazil in the Garden in our many gardens and events this summer.

Be sure to visit!


©2017 Chicago Botanic Garden and my.chicagobotanic.org

What is old is new again.

The dinosaur of the plant kingdom, a Wollemia pine tree (Wollemia nobilis), has surprised horticulturists at the Chicago Botanic Garden with a burst of promising male and female cones this winter.

In Glencoe, the sole tree spends its winters in the carefully controlled environment of the production greenhouse. In the wild, its relatives are clinging to life on remote sandstone gorges in the Blue Mountains of Australia.

“It is probably the most watched plant in the Garden right now,” said Boyce Tankersley, director of living plant documentation. Little is known about the prehistoric species that is part of a genus dating back 65 million years. The Garden’s specimen is a youthful 8 years old, and is just beginning to show off its unusual characteristics.

“In this case, there is such little information in the literature,” noted Tankersley, who was amazed to see both male and female cones emerging from the tree’s branches earlier this year. “We don’t know enough about this plant to know if it is going to set seed…but at least it is producing cones, which will allow us to try some experiments,” he said. The tree has grown male cones in recent years, but this is the first year it has produced any female cones.

PHOTO: Wollemia nobilis female cone.

Wollemia nobilis female cone

PHOTO: Wollemia nobilis male cone.

Wollemia nobilis male cone

Scientists do know that the species that has managed to survive the test of time possesses some unusual adaptations. It can generate new seedlings by dropping specific branches that take root, or it can exchange pollen from male to female cones to generate seed.  

At the Garden, scientists plan to pollinate the tree when the time is right. They will use pollen from the tree itself, and if available, pollen from a tree at another botanic garden. They will also reserve pollen for a potential future exchange.

PHOTO: Wollemia nobilis in the Heritage Garden in summer.

Find Wollemia nobilis in the Heritage Garden in the summer months.

Trees in the wild population are believed to be closely related to one another. As a result, any seeds they produce have a low level of viability. Only 6 percent or fewer go on to become healthy, mature trees. The species is listed as critically endangered. The urgency to save the pines is accelerated by changes in climate. Their mountain home is experiencing increasingly hotter and drier weather than ever before.

According to Tankersley, there is hope that more diversity may be found within the propagated plants, and that their offspring could lead to a stronger future for the species. However, scientists are only mildly optimistic. “In a world where there is so much that we can’t do anything about, it’s good to have something where you can participate in efforts to keep something from going extinct,” he said. “This plant is not gone; there’s something we might be able to do to help it out.” In addition, the plant may inform the research of paleobotanists who rarely have the opportunity to see a live plant with such historic roots to compare against the fossil record. “In a scientific way, we’ve been looking at the earth in a relatively short period of time,” added Tankersley. “When we find something like this that is very uncommon, everything about it is unknown…it’s sort of a miniature warehouse that we don’t want to lose because in the future, it may be more important than a mere botanical curiosity.”

The horticultural team also takes the cone production as validation that they are meeting the plant’s very particular growing requirements.

The Garden’s Wollemia pine spends its summers in the Australia bed of the Heritage Garden. Tankersley anticipates that it will be back on display this June.

As for the voyage of discovery with this extraordinary plant, he says, it is to be continued…


©2017 Chicago Botanic Garden and my.chicagobotanic.org