Search Results For "winter"

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

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

Why wait until spring? Plant a bulb container for a preview of blooms to come.

In this video, the Chicago Botanic Garden shows how to create a bulb garden in a pot for winter forcing so you can enjoy a preview of spring in the midst of winter’s chill. Forcing is the act of putting plants through a cold period in order to stimulate blooming during an atypical time of the year. By potting up your bulbs now, you’ll be able to enjoy a spring garden in your living room in ten weeks.

Shop 200+ bulbs at the Chicago Botanic Garden’s Fall Bulb Festival, October 8–9, 10 a.m. to 4 p.m. (Members hours: Friday, October 7, 10 a.m. to 4 p.m.)

What you need:

  • A shallow container with drainage holes
  • Enough spring bulbs to fill the container (plan on planting them close together, with an inch of space between bulbs)
  • Slightly moist potting soil

Assemble your container:

  1. Cover the bottom of the pot in one inch of soil.
  2. Add your largest bulbs in a layer, leaving approximately one inch between plants.
  3. Cover these bulbs. If adding another layer of smaller bulbs, leave 1½ inches of space from the top of the pot. Add the small bulbs in this layer, leaving one-half inch of space between plants. Fill with soil to within one-fourth inch of the rim.
  4. Lightly water the container.
  5. Place your container in a cool, dark location. The container must never get above 50 degrees or below freezing. Ideal spots are an unheated garage or, if you do a small pot, the crisper drawer of your refrigerator.
  6. In ten weeks your plants can be moved to a warm, sunny location. You should start to see growth within a week. (If you don’t want to bring your plants out at this time, they can hold  for several months in a cool location.)
  7. Once the plants begin to show flower buds, move to a less sunny location to prolong the blooming period.
  8. After blooming, plants should be discarded. Forced bulbs rarely transplant well into the garden.

The best plants for forcing tend to be on the smaller side. Tulips and narcissus work very well, especially the smaller cultivars. Larger blooms will require staking, especially if they don’t receive enough sunlight. Iris reticulata, Scilla siberica, Crocus, and Muscari are all wonderful bulbs for forcing: they stay small, and come in beautiful jewel tones that will brighten up any winter windowsill.  

PHOTO: Muscari 'Pink Sunrise'.

Muscari ‘Pink Sunrise’

Our Fall Bulb Presale ends Friday, September 30. Choose your specialty bulbs now and pick them up at the Fall Bulb Festival.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Black-Capped Chickadees Are Preparing for Winter

Year-round resident bird adds cheer to coming winter days

Sheryl DeVore Bailey —  September 14, 2016 — Leave a comment

Chick-a-dee-dee-dee.

Most people recognize that familiar call of the black-capped chickadee. It’s often heard in late summer and fall as chickadees gather in family groups and small feeding flocks to prepare for the winter.

The chickadee’s song—translated as “Hey, sweetie,” (though you can’t often hear the third syllable)—is reserved for late winter, spring, and summer, when the bird is courting and nesting. Nothing brightens a mid-February day more than when a chickadee sings because to those who hear it, the song signals spring’s arrival.

PHOTO: Black-capped chickadee (Poecile atricapillus). Photo © Carol Freeman.

Because of its curiosity and propensity to visit feeders, the black-capped chickadee (Poecile atricapillus) can often introduce youngsters and adults to bird-watching. Its telltale black cap and throat with white cheeks makes it easy to identify. Photo © Carol Freeman

The black-capped chickadee is the September bird species highlighted by the Forest Preserves of Cook County. Come #birdthepreserves with the FPDCC; there is a free walk at the Garden on September 17, 7:30 to 9 a.m.

The black-capped chickadee is considered a non-migratory species—it can survive the harsh winters of northern Illinois. These birds can lower their body temperature when sleeping at night, which protects them from freezing.

While some birds need to leave the region in fall because insects and other food will soon become difficult to find, chickadees know how to find insect larvae overwintering in tree bark (although flocks of chickadees do make small geographic movements, depending on food availability in colder months).

They also stash seeds to eat later, and unlike squirrels, they remember where they put them. Chickadees eat berries and animal fat in winter, and they readily come to feeders feasting on seeds and suet. Supplemental food, especially sunflower seed from feeders has been shown to help these little balls of feather and hollow bones survive when it gets really cold and wet outside. Those who feed birds can observe an interesting behavior in chickadees—they form a hierarchy, meaning the top chickadee gets to eat at the feeder first—it snatches a seed and leaves, then the second in command gets its turn.

PHOTO: A chickadee enjoys a plentiful and tasty treat in early February: berries.

A black-capped chickadee enjoys a plentiful and tasty treat in early February: berries.

In February, chickadees begin singing and looking for a cavity hole in which to nest—and there’s a wide variety of homes they’ll find suitable. They’ll choose abandoned woodpecker cavities and man-made nest boxes, or excavate their own small, natural cavities. Chickadees will nest in rotted, old wooden fence posts and abandoned mailboxes, and a pair once built a nest in an old shoe hanging from a line.

The female builds a cup-shaped nest with moss for the foundation, lining it with rabbit fur or other soft material. She has one brood each year, laying an average of seven to eight eggs. After 12 days of incubation, the young hatch, then remain in the nest for another 16 days. When they fledge, they continue to follow their parents, calling and begging for food. Come winter, they travel in small feeding groups, often with nuthatches, titmice, and other small songbirds.

West Nile, which came to the U.S. about 17 years ago, likely may not have affected black-capped chickadees as much as some thought, according to a recent study.

Though people were seeing fewer chickadees in their backyards and in woodlands when the virus came to the region, a 2015 study showed that overall black-capped chickadee numbers have not been affected by the mosquito-borne disease, especially compared with other species. Studies will continue on how the virus is affecting bird populations—but one thing is for certain—when the virus struck, it reminded humans not to take for granted the common birds they enjoy. And the black-capped chickadee is certainly a species that humans enjoy watching and hearing.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

Last year we discovered Viburnum leaf beetle (VLB) here at the Chicago Botanic Garden for the very first time. As I said then, “I strongly suggest you begin monitoring your viburnums for this critter” as once they move in, they become a perennial pest, just like Japanese beetles.

In early March, we monitored many of the Garden’s viburnums for signs of VLB egg laying and focused on areas where we observed VLB activity last summer. I had read recommendations for pruning out these twigs (with eggs) in the winter as a management technique and wanted to give it a go. To assist with this project, I called in our Plant Health Care Volunteer Monitoring Team; the more eyes the better. The six of us (all armed with hand pruners, sample bags, and motivation) began a close inspection with a focus on last season’s new twig growth for the signs of the distinctive straight line egg-laying sites. In less than five minutes, we found our first infested twig, pruned it out, and put it in a sample bag. After about three hours, we had collected about 20 twigs with eggs.

Truly, I was expecting to find a lot more. This was somewhat disappointing, as I had created a challenge to see which volunteer would fill his or her sample bag and collect the most. This turned out to be more like a needle in a haystack search, as it was a lot more difficult than I had thought. I also feel that the egg-laying sites would have been easier to see if we had done this in early winter, as the egg-laying locations had darkened with time.

Viburnum leaf beetle

Viburnum leaf beetle

Back at our lab, I dissected some of our samples under the microscope. When I removed the cover cap (created by the female after egg laying) material of a few of the egg-laying locations, I found about six orange, gelatinous balls (the overwintering eggs). These eggs were about a month or two from hatching.

For background on this new, exotic insect pest, please see my June 5, 2015, blog on the Viburnum leaf beetle.

American cranberrybush viburnum

American cranberrybush viburnum

  • The favored viburnums are the following:
  • Arrowwood viburnum (V. dentatum)
  • European and American cranberrybush viburnum (V. opulus, formerly V. trilobum)
  • Wayfaringtree viburnum (V. lantana)
  • Sargent viburnum (V. sargentii)
  • When to monitor and for what:
  • In early summer, you would look for the distinctive larva and signs of leaf damage from the larva feeding.
  • In mid- to late summer, you would look for the adult beetle and leaf damage from the beetle feeding.
  • In the winter, you would look for signs of overwintering egg-laying sites on small twigs.
  • Life cycle, quick review:
  • In early May, eggs hatch and larva feed on viburnum leaves.
  • In mid-June, the larva migrate to the ground and pupate in the soil.
  • In early July, the adult beetles emerge and begin to feed on viburnum leaves again, and mate.
  • In late summer, the adult female beetle lays eggs on current season twig growth in a visually distinctive straight line.

viburnum leaf beetle egg laying sites

Hopefully our efforts will lessen the VLB numbers for this coming season. We will see when we monitor the shrubs for leaf damage and larva activity in late May. If nothing else, it was a great learning experience with this very new, exotic insect.

Special thanks to the Plant Health Care Volunteer Monitoring Team: Beth, Fred, Tom (x3), and Chris.


©2016 Chicago Botanic Garden and my.chicagobotanic.org