Most perennials are deciduous. They go dormant when their above-ground parts die in the fall and then they rely on the energy and nutrient reserves stored in underground roots during the winter. But without a pretty blanket of snow all season, a garden can look drab and dead. Fortunately, there are some perennials with attractive and durable evergreen foliage that last the winter months, even in Chicago.

Why do they stay green so long? Well, evergreen leaves contain lignin, the same polymer in the cell walls of woody plants, throughout the veins and surrounding tissues. This makes them waxy, durable, and less prone to wilt or tear. These leaves are also less likely to get diseases or be browsed by critters. But the main reason for a perennial to have evergreen leaves is to provide a place to store energy and nutrients while they are dormant.

Evergreen perennials are quite trouble free but having modified leaves comes with a price. They are vulnerable to winter burn, a situation where the leaves become dehydrated, leading to injury or death. This can occur in late February or March, when sunlight is directly hitting the plant and the soil is still frozen. The sunlight heats up the leaves and causes them to transpire (lose water), yet the roots remain frozen and unable to replace what was lost. Fortunately, snow cover protects evergreen perennials by shading them and insulating the ground. Also, planting them on the north or east side of a structure will provide ample shade in late winter because the sun is lower.

The energy and nutrient reserves in evergreen leaves are utilized by new growth in spring. This is why most evergreen perennials do not shed their original leaves until the fresh leaves are complete. Older leaves can look shabby by spring, especially after some winter burn, but do resist the urge to cut them off in your garden until this transfer of reserves is complete. Prematurely removing evergreen leaves can weaken the plant and cause them to flower less.

Here are some of the best perennials with evergreen foliage for the Chicago area:

Bergenia cordifolia 'Bressingham White'

Summer: Bergenia cordifolia ‘Bressingham White’

Bergenia cordifolia 'Winter Glut'

Winter: Bergenia cordifolia ‘Winter Glut’

Bergenia, pigsqueak
(Bergenia cordifolia)

Bergenias have 1-foot-tall, leathery, paddle-shaped leaves that turn a mahogany color in the fall and winter. In early spring, clusters of pink flowers are held on thick stems. Blooms are sometimes seen during cooler weather in autumn. Plant bergenias in a partly sunny spot that is moist, but not wet. The common name, pigsqueak, comes from the sound that is made when rubbing a leaf between your fingers.

Helleborus x hybridus 'Blue Metallic Lady'

SPRING: Helleborus × hybridus ‘Blue Metallic Lady’

Helleborus x hybridus 'Solace'

Winter: Helleborus × hybridus ‘Solace’

Hellebore, Lenten rose
(Helleborus × hybridus)

Before the snow has even melted, you will find hellebores in flower. The common name, lenten rose, refers to the ability of this plant to bloom at the beginning of Lent. Green, white, and maroon are the most common flower colors found, and some have attractive spots on the inside. The evergreen foliage is less than 2 feet tall, coarse and leathery, and combines well with ferns and other woodland plants. Rich soil and shaded conditions suit it best and under such situations, self-seeding may occur.

Heuchera 'Carnival Rose Granita'

Heuchera ‘Carnival Rose Granita’

Coral bells
(Heuchera spp. and cvs.)

Coral bells are very popular today, and breeding efforts have led to an overwhelming amount of options to choose from. The maple-like leaves can range from burgundy to black, caramel to red, and chartreuse to silver. Flowers have gotten showier and last much longer too. If afternoon sun is avoided, and the soil is well-drained, they are tough perennials that remain visible all winter long.

Liriope spicata

Liriope spicata is green all summer—and winter—long.

Creeping lilyturf
(Liriope spicata)

Creeping lilyturf is a tough, drought-tolerant groundcover for sun or shade. It spreads by rhizomes and makes a nice alternative to grass, provided you don’t plan to tread on it very much. It also competes well with tree roots. In autumn, the plants produce interesting spikes of violet flowers (sparingly) that lead to black, shiny fruits that look like beads. Variegated cultivars are available too.

Japanese pachysandra
(Pachysandra terminalis)

Japanese pachysandra is an extremely common groundcover for shaded landscapes. It spreads quickly and, once established, remains weed and maintenance free. The glossy dark green foliage is attractive year round, and in spring it boasts fragrant, ivory white flowers. There is also a pachysandra that is native to the Appalachians.  It is called Pachysandra procumbens and it too forms an evergreen groundcover, though much more slowly over time.

Pachysandra terminalis

Spring: Pachysandra terminalis

Barren strawberry
(Waldsteinia ternata)

Barren strawberry is a superb, 2-inch-tall, groundcover for sun or partial shade. The plants are stoloniferous, like strawberries, and spread quickly into a weed-proof mat in well-drained soil. In mid-spring, barren strawberry is loaded with sunny yellow flowers that have five petals each. Hailing from Europe, Japan, and China but a native species, Waldstenia fragaria, has very little difference in habit or growing conditions.

Pachysandra terminalis

Winter: Pachysandra terminalis

Polystichum acrostichoides

Polystichum acrostichoides emerges under melting snow

Christmas fern
(Polystichum acrostichoides)

Native to Chicago and the eastern United States, Christmas fern is one of the few truly evergreen ferns that are effortless to grow. All it needs is some shade and a well-drained spot, and in a few years, you will have a sizable 2-foot-tall plant, forming a 2-foot-wide clump. In spring, cute fuzzy fiddleheads emerge out of the dark former fronds. You can start your own colony of Christmas ferns by digging up mature plants and dividing them into additional ones.

Barren strawberry
(Waldsteinia ternata)

Barren strawberry is a superb, 2-inch-tall, groundcover for sun or partial shade. The plants are stoloniferous, like strawberries, and spread quickly into a weed-proof mat in well-drained soil. In mid-spring, barren strawberry is loaded with sunny yellow flowers that have five petals each. Waldsteinia ternata hails from Europe, Japan, and China. The common name, barren strawberry, is shared with another species, W. fragariodes. The latter is native to the United States; however, nurseries offer it much less frequently than W. ternata.

Waldsteinia ternata

Winter: Waldsteinia ternata

Waldsteinia ternata

Spring: Waldsteinia ternata


©2017 Chicago Botanic Garden and my.chicagobotanic.org

2016’s Award-Winning Books on Botany & Horticulture

Available at the Lenhardt Library

Leora Siegel —  December 22, 2016 — Leave a comment

Winter is the time to curl up by a fire with all the books you didn’t get to this summer—and this year had some fantastic reads in botany and horticulture. But how do you know what to pick up in a sea of books?

Each year at its annual conference, the Council on Botanical and Horticultural Libraries (CBHL) awards prizes for the best new works in botany and horticulture that contribute to the body of literature in these fields. Not surprisingly, a selection of these award-winning books are available to be borrowed from the Lenhardt Library. Here are our top four picks—find them online, or check them out on-site on your next Garden visit.

Shopping online? Order through our Amazon Smile link; a portion of your purchase is donated to the Garden.

2016 Award for Significant Contribution to the Literature of Botany or Horticulture:

The Curious Mister Catesby: A Truly Ingenious Naturalist Explores New Worlds

The Curious Mister Catesby: A “Truly Ingenious” Naturalist Explores New Worlds
by E. Charles Nelson and David J. Elliott ; foreword by Jane O. Waring

University of Georgia Press, 2015. (Wormsloe Foundation Nature Book Ser.)

456 p.; 238 paintings, illustrations, photos, and maps

ISBN 9780820347264 (hardcover)

Lenhardt Library call number: QH31.C35C87 2015


2016 Award of Excellence in Botany:

On the Forests of Tropical Asia Lest the Memory Fade

On the Forests of Tropical Asia: Lest the Memory Fade
by Peter Ashton

Royal Botanic Gardens, Kew, in association with the Arnold Arboretum of Harvard University, 2014

ix, 670 pages; color photos, illustrations, and maps

ISBN 9781842464755 (hardcover)

Lenhardt Library call number:  SD219.A84 2014

2016 Award of Excellence in Plant Identification & Field-Guides:

California mushrooms: The Comprehensive Identification Guide

California Mushrooms: The Comprehensive Identification Guide
by Dennis E. Desjardin, Michael G. Wood, and Frederick A. Stevens

Timber Press, 2015

559 pages; color photos

ISBN 9781604693539 (hardcover)

Lenhardt Library call number: QK605.5.C2D47 2015

2016 Award of Excellence in Biography:

James Sowerby: The Enlightenment’s natural historian

James Sowerby: The Enlightenment’s Natural Historian
by Paul Henderson

Royal Botanic Gardens, Kew, 2015

336 pages; 150 color plates, 30 halftones

ISBN 9781842465967 (hardcover) 

Lenhardt Library call number: QH31.S69H46 2015

CHBL is the leading professional organization in the field of botanical and horticultural information services. It is comprised of librarians who work in botanic garden libraries across North America and in university libraries focused on botany and agriculture. Several Lenhardt Library staff (Leora Siegel, Stacy Stoldt, and Donna Herendeen) have served as CBHL board members in the past—and at present.

To learn more about CBHL, visit www.cbhl.net.

Members have borrowing privileges—become a member today!


©2016 Chicago Botanic Garden and my.chicagobotanic.org

This past summer, the Chicago Botanic Garden joined an intrepid team of plant collectors from four other American institutions on an expedition to the Republic of Georgia.

Our focus: to collect seeds to diversify the genetic diversity of ex-situ plant collections; to bring back and evaluate species for their ornamental potential; and to provide a hedge against natural and man-made disasters—all while building upon institutional collaborations developed during previous expeditions.

The PCC16-Georgia group poses at the Old Omalo Guest House in the Tusheti Region, Georgia.

The PCC16-Georgia group poses at the Old Omalo Guest House in the Tusheti Region, Georgia. From left to right: Joe Meny (US National Arboretum), Peter Zale (Longwood Gardens), Boyce Tankersley (Chicago Botanic Garden), Vince Marrocco (Morris Arboretum), Koba (owner of Old Omalo Guest House/Hotel Tusheti), Matt Lobdell (The Morton Arboretum), Temuri Siukaev (driver), Koba’s daughter, Constantine Zagareishvili (driver), Manana Khutsishvili (botanist), David Chelidze (botanist)

Map showing the location of the Republic of Georgia.

Just east of the Black Sea is the Republic of Georgia. Map courtesy worldatlas.

The Republic of Georgia was chosen because it is the only biodiversity hotspot that is situated within the temperate climatic zones.

Over millennia, the high peaks of the Greater Caucasus Mountains to the north, Lesser Caucasus Mountains to the south, and their inter-connecting mountain ranges situated between the Black Sea to the west and Caspian Sea to the east have provided a refuge for species that have gone extinct elsewhere due to glaciation and other climate extremes.

Tucked into hundreds of microclimates created by this varied topography, many of these endemic species (found nowhere else on earth) are perfectly hardy in American, Russian, and European gardens much farther north. 

Coordinating the trip on the Georgian side were our colleagues from the Institute of Botany, Tbilisi and Bakuriani Alpine Botanical Garden. They provided invaluable logistical support through the use of two of the foremost botanists in the region, drivers, vehicles, and places to stay.

The varied topography of the Tusheti Region.

The varied topography of the Tusheti Region.

Bakuriani Alpine Botanical Garden, Institute of Botany, and American collectors at Bakuriani Field Station.

Bakuriani Alpine Botanical Garden, Institute of Botany, and American collectors at Bakuriani Field Station

In a little more than two weeks in the field, the group traveled more than 1,100 miles from the high—and barely accessible—Greater Caucasus Mountains of the Tusheti region in northeastern Georgia, through the central valleys, to Lake Tabatskuri in the Lesser Caucasus Mountains in the south, between the Tetrobi Reserve and Bakuriani Alpine Botanical Garden.

The central valley separating the Greater and Lesser Caucasus mountain ranges.

The central valley separating the Greater and Lesser Caucasus mountain ranges

Lake Tabatskuri is situated between the Tetrobi Reserve and Bakuriani Alpine Botanical Garden; the Lesser Caucasus mountain peaks are in the distance.

Lake Tabatskuri is situated between the Tetrobi Reserve and Bakuriani Alpine Botanical Garden; the Lesser Caucasus mountain peaks are in the distance.

The geographic location of Georgia (Russia to the north, Central Asia to the east, Persia to the south and Asia Minor, the Middle East, and Europe to the west) has made this region a favorite transit point for merchants. Tucked into remote mountain valleys are small communities created from the descendants of Greeks, Germans, Hebrews, Persians, Armenians, Turks, Russians, Circassians, Huns, Mongols, and more, with remnants of each people’s own unique culinary, religious and linguistic traditions.

It was also, unfortunately, a thoroughfare for invading armies. Ancient fortifications, places of worship, homes—all show evidence of destruction and rebuilding.  

Samshvilde Fortress ruins.

Samshvilde Fortress ruins

Fortified towers are a typical feature of many homes in the Greater Caucasus mountains.

Fortified towers are a typical feature of many homes in the Greater Caucasus mountains.

Church of St. George.

Church of St. George

The collections wrapped up with a foray into western Georgia (ancient Colchis in Greek mythology) in and around Kutaisi, the legislative capital and its third largest city. A brief visit to the Kutaisi Botanical Garden was in order here, before we left the region. A highlight: a small shrine built inside a living 450-year-old oak. 

In all, 205 different seed lots and herbarium vouchers—representing 169 different species of trees, shrubs, perennials, and bulbs—were collected, including six of seven species of Quercus (oaks) in support of the IUCN Redlist of all of the Quercus in the world.

Religious shrine built inside a 450-year-old Quercus hartwissiana at Kutaisi Botanical Garden.

A religious shrine is built inside this 450-year-old Quercus hartwissiana at Kutaisi Botanical Garden.

What a haul! Seed collectors admire hundreds of seed collections to be cleaned.

What a haul! Admiring hundreds of seed collections to be cleaned are (left to right): Dr. Fritz, Dr. Tatyana Shulina (Garden consultant), Dr. Manana Khutsishvili (lead Georgian botanist) and Dr. Marina Eristavi (botanist on a former trip).

While we each came away with a fantastic collection of seed to propagate, this trip was about much more than collecting plants. Our journey’s end featured a meeting with representatives of institutions from America, Armenia, Azerbaijan, and Georgia all focused on expanding collaboration to match areas of expertise with areas of need—not only in the area of collections, but also horticulture, conservation science, education, and fundraising/collaborative grants.

The Caucasus Regional Meeting Participants pose on balcony at the of Institute of Botany. The ancient Narikala Fortress of Tbilisi is in the background.

The Caucasus Regional Meeting participants pose on balcony at the of Institute of Botany. The ancient Narikala Fortress of Tbilisi is in the background.

Left to right: Dr. Marine Eristavi, conservation scientist, National Botanical Garden of Georgia, Dr. Tinatin Barblishvili, deputy director, National Botanical Garden of Georgia, Dr. Lamara Aieshvili, curator of rare and endemic plants of Georgia ex situ collection, National Botanical Garden of Georgia, Vince Marrocco, horticulture director, Morris Arboretum, Dr. Manana Khutsishvili, botanist, Institute of Botany, Tbilisi, Dr. Peter Zale, curator and plant breeder at Longwood Gardens, Matt Lobdell curator of The Morton Arboretum, Dr. Fritz, Dr. Tatyana Shulkina, former curator of the living collections of the Soviet Union, Komarov Botanical Garden and currently Chicago Botanic Garden consultant, Dr. Rashad Selimov, head of education, Institute of Botany Azerbaijan Academy of Sciences, Baku, Joe Meny from the US National Arboretum, Dr. Vahid Farzaliyev, National Botanical Garden Azerbaijan Academy of Sciences, Baku, Boyce Tankersley director of living plant documentation at the Chicago Botanic Garden, Dr. Shalva Sikharulidze, director of Institute of Botany, Georgia and Bakuriani Alpine Botanical Garden, Dr. George Fayvush, Department of Geo-botany Armenian Academy of Sciences, Yerevan, Dr. Zhirayr Vardanyan director of the Institute of Botany and National Botanical Garden Armenian Academy of Sciences Yerevan

What can we expect from our efforts? New blooms in the Garden! We have added quite a few plants to those brought back from Georgia on three previous trips:

Lilium monadelphum

Lilium monadelphum

Muscari armeniacum

Muscari armeniacum

Tulipa undulatifolia

Tulipa undulatifolia

Bellevalia makuensis

Bellevalia makuensis

Campanula lactiflora

Campanula lactiflora

Gentiana schistocalyx

Gentiana schistocalyx

Stachys macrantha

Stachys macrantha

Stokesia major

Stokesia major

Dianthus cretaceous

Dianthus cretaceous

Iris iberica ssp. Elegantissima

Iris iberica ssp. elegantissima

Verbascum pyramidatum

Verbascum pyramidatum

Colchicum trigyna

Colchicum trigyna

Stay tuned! Invitations have been received from institutions in Armenia, Azerbaijan, and Georgia for future plant collecting trips to the region. Likewise, scientists from these countries were invited to collect American native plants to increase the biodiversity of their ex-situ collections.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

So you think you’re an ace tree identifier. Those big scalloped leaves are from oak trees, the three-fingered hand shapes are maple leaves, those little oval leaves marching in a double line along a stem are from an ash—boo yah!

OK, now do it without any leaves.

And yes, you can…with a little help from Jim Jabcon, assistant ecologist for natural areas. The other day Jabcon, walked me through the McDonald Woods and began my education.

PHOTO: Paperbark maple (Acer griseum) bark.

Paperbark maple (Acer griseum)

Jim Jabcon is giving a class on Identifying Trees and Shrubs in Winter on December 10. Sign up today!

First, he corrected my misinformation. I always thought the trick was looking at the tree’s habit—its size and shape. But no—especially not in a natural woodland like this. A tree’s habit depends on where it is growing—how crowded it is by other trees and what it has to do to catch some sunlight.

“Any tree will change its habit depending on what is given to it,” he said as we walked into the woods. “You can probably get 100 trees in a row, but it’s like a fingerprint. They all have different spaces, different light; they’re all going to be different.”

Still, there are some distinctive shapes. Does the tree have thick branches, even at its top with a fearsome, gnarly look worthy of a horror movie? Jabcon nodded at a towering behemoth that could have played a role in The Exorcist: it was an oak.

But let’s start with a major clue: bark.

Jabcon cast a practiced eye—an artist’s eye, in fact, for his degree is in fine art—over the trees. He pointed out a tall tree whose trunk was covered in thick, rough bark.

That bark is the giveaway. The tree was an oak; the tough bark is its secret to surviving fires.

PHOTO: Black walnut (Juglans nigra) bark.

Black walnut (Juglans nigra)

Nearby, another tree boasted thick bark with a rugged geometry, forming blocky rectangles running vertically up the tree in a kind of forest version of cubism.

“This is your black walnut,” Jabcon said. “It’s got a really good knobby bark.”

It also had another tree, a small sapling, growing in a crook about 5 feet up. Jabcon pulled it out and showed how its slender reddish branches were covered with a white chalky material that scraped off easily. “This is your box elder, in the maple family,” he said.

And further along the trail was a tree that won my heart because it looked like another part of a human body.

Its smooth, gray trunk was wrapped in bark with the sinewy look of muscle.

That was because the tree was a muscle wood—the common name for an American hornbeam, bestowed because of the signature appearance of its bark.

PHOTO: American hornbeam or muscle wood (Carpinus caroliniana) bark.

American hornbeam or muscle wood (Carpinus caroliniana)

Walking on, we stopped at another tree with its own distinctive bark, which looks like big hunks of bark pasted onto the trunk and separated by deep grooves. That “warty” bark, as Jabcon put it, identified it as hackberry. (Celtis occidentalis)

Blogger Kathy J. gives you a Tree 101 on hackberry in her post This Bark is Rough.

Still, bark isn’t the only clue. Jabcon pulled a slender branch close and examined the leaf buds running along its length.

They were in neat pairs, each bud opposite another. “Very few trees have opposite leaf buds,” he said. “Ashes. Maples. So if you’ve got opposite buds you can narrow it down.”

To make the final ID, he examined the terminal bud—the bud at the very end of the branch. It consisted of a cluster of three tiny points, making the branch look almost like a miniature deer hoof. That distinctive shape settled it: this was a white ash.

And so it went as we wandered through the woodland.

We looked at leaf buds, like the sulphur yellow leaf ones (“I love how cool they are,” Jabcon said) on a bitter nut, one of his favorite trees.

We looked at terminal buds, like the super-long ones that look like a goose’s bill and mark it as a nannyberry, a kind of viburnum.

PHOTO: Shagbark hickory (Carya ovata) bark.

Shagbark hickory (Carya ovata)

We looked at bark, like the one hanging in huge strips off a tree. It was a shagbark hickory. This tree’s bark has peeled off in such big pieces that bats have hibernated beneath them.

And if all else fails, there is another clue still there in winter, though soon it could be hidden under snow.

“It’s OK to cheat and look at leaves on the ground,” Jabcon said cheerfully, picking up a few oak leaves to prove the point. “They’re still there.”


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Some of the star attractions of Wonderland Express at the Chicago Botanic Garden are the dozens of beautiful dwarf conifers used to create Chicago in miniature. What you might not know is that many of these conifers are great plants for the Chicago area and can easily be incorporated into your home landscape.

Dwarf conifers are a good way to add four-season interest and wildlife habitat to your yard, and with their unique colors and growth habits, they are practically living sculptures. I’ve selected four of my favorite interesting and unique conifers (found in Wonderland Express—go check them out) that are hardy in the Chicago region.

Picea englemanii 'Bush's Lace'

Picea englemannii ‘Bush’s Lace’ features elegantly draping stems.

Picea omorika 'de Rutyer'

Picea omorika ‘de Ruyter’ displays bright blue needles.

Engleman spruce (Picea engelmannii ‘Bush’s Lace’) is a tall, powder blue spruce that is grown for its upright habit and pendulous side branches. Unlike some evergreens, this spruce will keep the gorgeous blue color throughout the year. This tree thrives in the extremes of Chicago’s summers and frigid winters. It is a vigorous plant and will often put on two feet of growth in one season, so make sure to plant it somewhere where it has some room. Engleman spruce are happiest in full sun with well-drained soil. A mature specimen of this tree can be found in the Dwarf Conifer Garden.

De Ruyter Serbian spruce (Picea omorika ‘de Ruyter’) is another spruce that will thrive in the Chicago region. Serbian spruce typically feature dark green needles with silver undersides that shimmer in the breeze, but on this variety, the silver is on top, making for a pop of silvery blue on each branch. This is a slower-growing cultivar, often growing only six to eight inches a year in a loosely conical shape. Because it is a spruce, it requires full sun and well-drained soil to look its best. There is also a large specimen of De Ruyter in the Dwarf Conifer Garden.

Pinus mugo 'Tannenbaum'

Pinus mugo ‘Tannenbaum’ holds its beautiful green color all winter.

Tannenbaum mugo pine (Pinus mugo ‘Tannenbaum’) is a twist on a classic mugo pine. Most people are familiar with mugo pines as the little round pines that often resemble boulders in the landscape. Tannenbaum, as the name suggests, is an upright form that grows as a perfect green pyramid, with the classic Christmas tree shape. It is a relatively slow-growing plant—approximately six inches per year—and holds its dark green color all year. Mugo pines are amazingly hardy and should do well throughout the Chicago area, provided they receive full sun and have relatively well-drained soil.

Glauca Prostrata noble fir (Abies procera ‘Glauca Prostrata’) grows as a creeping mat of icy blue foliage. Weeping blue noble fir makes an unusual addition to the landscape due to its rounded needles, unlike the similar weeping Colorado blue spruce, which has incredibly sharp needles. This makes it a far better choice for placing near walkways. This slow-growing plant averages four to six  inches of growth a year, eventually forming a clump about two feet tall and about six feet wide. As with other conifers, this noble fir prefers full sun and well-drained soil.

Abies procera 'Glauca Prostrata'

Abies procera ‘Glauca Prostrata’ stands out among the surrounding greenery.

Top tips for keeping your conifers happy:

  1. Most conifers prefer full sun and have very little shade tolerance. All of the trees in this article prefer full sun.
  2. Conifers are generally adapted to areas with well-drained soil. Avoid places that stay wet to prolong the life of your plant.
  3. Avoid windy locations. Because conifers keep their needles all year, it is best to site them in less exposed places so they don’t dry out and lose their needles.
  4. Water thoroughly in the fall. You only have once chance to make sure the plant has enough water before the ground freezes and you can’t water it anymore. If we have a dry fall, it is helpful to water your newly planted trees until the ground freezes so they have enough water to last the winter.

©2016 Chicago Botanic Garden and my.chicagobotanic.org