Thankfully, the bright, blooming containers in the Heritage Garden at the Chicago Botanic Garden were planted this week, welcoming spring and warm fuzzies along with them. Just standing near these spring annuals makes us happy, and for horticulturist Tom Soulsby—who’s been planting these signature troughs for the past 15 years—it’s one of his favorite things to do each spring.
The bright, colorful troughs in the Heritage Garden welcome visitors every spring.
“After a long, drawn-out winter, it’s nice to have something that cheers people up,” said Soulsby. “It cheers us up, too, to see visitors smiling.”
Horticulturist Tom Soulsby uses small, visually interesting plants that would otherwise get lost in a mass planting in the Garden.
People look forward to these 41 containers each spring, which is something Soulsby keeps in mind when he’s planting them. By the time April rolls around, people are craving lush, overflowing color after months of dreary gray, so he “overplants” the troughs to make them look full from the get-go.
Poking through the red, orange, and yellow flowers this year is an unusual, edible treat: some Lactuca sativa ‘Australian Yellowleaf’ lettuce. “I’ve never used lettuce before in a container, but it’s a fun alternative for foliage accents, and can tolerate cooler weather,” said Soulsby.
Lactuca sativa ‘Australian Yellowleaf’ lettuce is a fun foliage accent for a container, and a tasty snack.
That’s another trick: all of the plants Soulsby picked for these troughs can handle cold and a light frost (but we’re hoping they won’t have to). Some—like the Narcissus ‘Fruit Cup’ daffodils and Tulipa praestans ‘Shogun’ tulips in this year’s troughs—will bloom later. It’s all about balance, Soulsby said—finding a mix of plants that will bloom at varying times.
We’re loving the bright, sunny color of Primula vulgaris ‘Kerbelnec’ Belarina® Nectarine in these troughs.
Here’s hoping Mother Nature takes a cue from these troughs.
“The wonder of the world, the beauty and the power, the shapes of things, their colours, lights and shades—these I saw. Look ye also while life lasts.” —Anonymous lines found on an old tombstone in Cumberland, England
“While life lasts.” This can be a very brief moment in time for a spring ephemeral. In that narrow window that exists between thawing ground and the leafing out of the tree canopy, spring ephemerals—those woodland wildflowers that emerge, then quickly go dormant—live their life.
White trout lilies (Erythronium albidum)
If you want to see some of the spring woodland flowers in bloom, you often have to be there on the day. In the McDonald Woods at the Chicago Botanic Garden, sometimes all you find are petals scattered on the ground, and you realize you have to wait another year. This is particularly true of species like bloodroot (Sanguinaria canadensis), whose blossoms only last for a day before they drop. Additionally frustrating is that cloud cover can hamper catching the full glory of the blooming of some species. You may show up on a sunny morning only to have the blossoms close up before your eyes. Species like spring beauties (Claytonia virginica) will only open in the full sun and will close again if clouds appear. This response to sunlight may be the result of temperature or light. Some ephemerals might provide longer viewing opportunities, since they hold their flowers for a longer period of time, or have many more plants that flower on different days.
Most of the spring ephemerals are perennial. They have underground organs—bulbs, corymbs, etc.—that store nutrients to be used for producing leaves and flowers in succeeding year. White trout lilies (Erythronium albidum) are a good example. The trout lilies, both white and yellow species, derive one of their common names from the mottled leaves that some think resemble the markings on a trout. (Other common names include adder’s tongue and dog-toothed violet—the second name is curious because these are plants in the lily family, having no relationship to violets.)
Trout lilies also spread by underground rhizomes that form clumps, often covering large patches in the woodland, the mottled leaves camouflaging their abundance, only to become dazzling drifts of white when the sun appears. If you have time, you can come out to the woodland early in the morning and watch the white petals of the trout lilies curl back and expose their yellow anthers to the sun—and pollinators.
There are also a few annual spring ephemerals. False mermaid (Floerkea proserpinacoides) is a spring ephemeral annual. Unlike many of the other ephemerals, false mermaid is inconspicuous in that it is a small, ferny green plant with tiny greenish flowers. Portions of the nature trail in the McDonald Woods are surrounded with acres of this species in spring. Even in these large numbers, without close inspection, it is difficult to tell when they are in flower. This species is dependent on its flowers producing one to three large seeds to be able to reproduce itself after the plant turns yellow and dies.
Many of the spring ephemerals depend on native bees for their pollination.
The trout lilies are visited by an oligolectic bee (Andrena erythronii). “Oligolectic” means this is a bee that has a narrow, specialized pollen preference, typically for the pollen of a single genus of plants. The species name of this bee, erythronii, refers to the genus of the trout lily, Erythronium. Another ephemeral with an oligolectic bee pollinator is the spring beauty. The bee that is a specialist of this ephemeral, with its attractive pink-striped flowers, is Andreana erigeniae.
While these plants often have specialist pollinators associated with them, they usually have several different pollinators that can visit, including other native bees and many species of flies.
For ephemerals in the genus Dicentra, such as Dutchman’s breeches and squirrel corn (Dicentra canadensis), queen bumblebees are an important pollinator. These ephemerals have tightly closed flowers, requiring significant strength to enter the flower and access the pollen and nectar. The large queen bumblebees are among the few pollinators equipped to gain access. This is not only important for the plants, it is also important for the bumblebees. Many native bees colonies die off in fall, leaving the queens to overwinter and start the new colonies in spring. These large, fuzzy bees are able to manufacture enough physiological heat, by vibrating their wing muscles and restricting their blood flow in the thorax, to get themselves flying early in spring before it’s warm enough for many other pollinators to go foraging for resources to start the new colonies. The spring ephemerals provide this important resource.
Besides being important sources of nectar and pollen for native insects, the spring ephemerals also serve the purpose of saving soil and reducing water runoff during a time of year when few other plants are growing.
Trout lilies, for example, have very efficient photosynthetic abilities and take advantage of the high light levels available in the spring woodland. This strong photosynthetic response requires large quantities of water to maintain the process. Therefore, abundant populations of this species and other ephemerals absorb large quantities of water that would otherwise move off site, often carrying valuable nutrients and soil with it. This high demand for moisture also causes the ephemerals to have shorter flowering periods in times of drought. In your yard, you can encourage ephemerals to flower longer during dry conditions by providing a little extra water. There is also some thought that the rapidly decomposing foliage of these “short-lived” plants provides readily available nutrients for other plants that begin growing later in the season.
One other fascinating thing about spring ephemerals is that essentially all of them rely on ants to disperse their seeds. This relationship is referred to as myrmecochory—”myrmex” being the Greek word for ant.
Each seed of the spring ephemerals has a structure called an elaiosome attached to its surface that attracts ants. The elaiosome is rich in lipids and proteins. The ants take the seeds back to their nests and consume the elaiosome as food, after which they bring the seed to the surface and deposit it on their trash piles, where the seeds tend to germinate in a rich, organic seedbed.
I include another plant with elaiosomes in the list of spring ephemerals. This is parasol sedge (Carex umbellata). This grass-like, early-flowering sedge produces most of its seeds very close to the soil surface, where ants are more likely to find them. It is not uncommon to find ants nesting at the base of these plants. I often get questions from people who have planted ephemerals in their yard, but say they don’t see seedlings, while their neighbors are finding them on their property. It is more than likely that the neighbors have the ant colony that is harvesting the seed and sowing them at the neighbors’.
Parasol sedge (Carex umbellata)
Given that the spring ephemerals are adapted to growing in a cool, moist environment and highly dependent on early spring pollinators, climate change is likely to cause stress in the system. Early warming and possibly drought conditions in spring may disrupt pollinator interactions or shorten flowering periods, making seed production more difficult, or reducing the amount of time ephemerals have for storing nutrients for future flowering.
False rue anemone (Isopyrum biternatum)
With spring on the horizon, you should make plans to visit the McDonald Woods to view the diversity of colorful spring wildflowers. For those of you taking pictures, pay attention to weather forecasts, and be mindful of the potential to damage other vegetation while attempting to get the perfect shot.
Pollinators are crucial to the health of the planet, helping with everything from the food we eat to the cycle of life. At the free Unearth Science festival this weekend, the Chicago Botanic Garden will celebrate pollinators with activities including a workshop on making native bee homes. We’ve got a sneak peek for you below.
Did you know that native bees are better and more efficient pollinators than honeybees when it comes to fruit trees? Honeybees carry pollen in sacks on their hind legs, which doesn’t always make it to the stigma of the flowers they visit (anthers are where the pollen grains are picked up; stigma is where they are deposited for successful pollination). Mason bees (Osmia lignaria) carry pollen all over their bodies, which means that the pollen has a greater chance of reaching the stigma for proper pollination. One mason bee can pollinate as many flowers as 100 honeybees.
Mason bee (Osmia lignaria)
Mason bees pollinate a wide variety of flowers, in addition to fruit trees, with a particular emphasis on the rose family. They are generalists though, so they pollinate many types of vegetables too. If you are interested in growing fruit trees and vegetables in your yard, you may want to attract and support more mason bees.
Are you avoiding bees because they sting? Another reason to invite mason bees into your yard is that they are nonaggressive. Honeybees and bumblebees may defend their nests if disturbed, so bee skeps—or domed hives—are usually located on larger plots of land, not in typical backyards. Male mason bees do not have stingers, and the females only sting if they are trapped, so there is little reason to fear them.
We asked horticulture program specialist Nancy Clifton for a preview of her workshop at the Unearth Science festivalwith Northwestern University graduate student Marie Faust. The workshop, Native Bee Homes, is a free event that requires registration. You’ll find instructions for how to make a mason bee home below. Bring your questions about pollinators and other science-related topics to the festival, where dozens of scientists and horticulturists will be happy to answer them.
Fill the metal can with as many reeds as you can tightly pack inside. Ensure the open ends of the reeds are facing out. Use duct tape to encircle the parts of the reeds that are sticking out of the can.
Step 2
Cut three strips of bark ribbon to wrap around the can and the duct-taped extension. Use bits of Cling adhesive to adhere the bark ribbon to the can in three sections, so it is completely covered.
Step 3
Cut two 8-inch-long pieces of bark ribbon and duct tape them together along the long edge. Place this over the top of your can as a roof. You want to create a small gable that overlaps ½ inch over the end of the tube to keep the reeds dry when it rains.
Step 4
Use bits of Cling to adhere the roof to the house. If needed, further secure the roof with two rubber bands. Place the completed bee house fairly in a protected area, against a flat surface with a southwest exposure. Placing the house fairly high up ensures that bees will not mingle with people when entering and exiting their new home.
Leave your house out all summer and you should find mason bees filling the tubes with larvae. For information about storing and incubating mason bees for next year, visit seedsavers.org.
Sign up for the free workshop on making native bee homes with horticultural specialist Nancy Clifton and Northwestern University graduate student Marie Faust at the Unearth Science festival, April 20–22, 2018. You’ll make your own native bee home just as described above.
It’s that time of year when the sun finally comes out and temperatures go up, allowing you to get some outdoor planting done. But beware the fickle Chicago spring.
Don’t let frost take out all of your plants (and hard work). Cover less hardy plantings or move them into sheltered areas if temperatures dip below freezing.
Perfect gardening days are sometimes followed by colder temperatures that can wreak havoc on your newly installed containers. Horticulturist Heather Sherwood shared some of the things she does to protect plants that the home gardener may want to do as well.
Move containers inside. Sherwood’s team planted large containers with a mix of flowers, including foxglove and Persian buttercup. In cold weather, the containers are moved into McGinley Pavilion, which has plastic draping down to keep the cold out. If you’ve started to create containers for your back porch or balcony, bring them inside. Even an uninsulated shed offers more protection than none.
Not all containers are easy to relocate indoors. Some of our spring annual display containers weigh more than 200 pounds, and stay where they are through the cold. Sherwood covers the ones that can’t be moved with plastic, including used soil bags. If you were planning on just disposing of your empty soil bags, reuse them this way to protect your containers instead. Sherwood also recommends covering plants with old bedding, especially fitted sheets. They fit snugly around the bottom of the containers and keep out the cold air.
If you do cover your containers, it may be helpful to prop up the covering with bamboo poles. The covering shouldn’t touch the plants, because it can weigh down and crush any leaves or fresh blooms. And if the temperatures drop too low, the covering can freeze to the plant and damage it. Circulation is always good, so give your plants “breathing room” if you cover them.
Leave some plants alone. Some flowers don’t need your fretting. Pansies will likely withstand colder temperatures. Daffodils and tulips, some of which haven’t even emerged yet, will probably also be fine. Focus your efforts on protecting the more vulnerable flowers and let the hardy ones tough out the cold.
Protect the containers. Your plants won’t stand a chance if you don’t also protect the containers you’ve planted them in. If you use terra cotta pots, keep them dry in cold temperatures. If they’re wet and then freeze, cracks can form. Containers made from fiberglass and plastic will degrade over time if they’re in direct sunlight, so check these for damage and move inside if you’re unsure of their durability. Your reused containers will last much longer if you have stored them out of the elements over winter. (Make a mental note for next winter.)
Container plantings in the English Walled Garden are covered lightly with soil bags.
Heavier frost blankets are stapled around tree trunks to protect displays around the Regenstein Center.
Still not sure what to do with your containers? Contact Plant Information at the Garden at (847) 835-0972 or plantinfo@chicagobotanic.org with any questions. The master gardeners and horticulture specialists who run this service can help you figure out what’s best for your plants.
When spring unfurls, the trillium are among the stars of the native wildflowers—and in coming years, the show at the Chicago Botanic Garden will be even more spectacular.
A ground-level view of forest trilliums in spring bloom
White trillium (Trillium grandiflorum)
Little sweet Betsy (Trillium cuneatum)
Yellow wakerobin (Trillium luteum)
The Chicago Botanic Garden is collaborating with the Huntsville Botanical Garden in Alabama on a Trillium conservation program for the beloved woodland flower. The Huntsville Botanical Garden has one of the most complete collections of Trillium in the United States. In April, Andrew Bunting, assistant director of the Chicago Botanic Garden and director of plant collections, will pick up carefully selected rhizomes, or underground horizontal stems, from Huntsville’s collection.
Biota of North America Program (BONAP) map of Trillium in the United States
When he returns, the rhizomes will be grown out in the nursery, and in two to three years, the Trillium plants will be replanted in areas to be determined throughout the Garden.
Currently, the Chicago Botanic Garden has eight species of Trillium growing in the McDonald Woods, the Sensory Garden, the Native Plant Garden, and Lakeside Garden. If all goes well, the Huntsville transplants will bring dozens of more taxa, or individual types of plants, to the Garden.
When we began our collaboration with Huntsville, we catalogued each of its Trillium species to evaluate which ones from its collection might grow in our limestone-based soils and USDA Zone 5 growing conditions. Typically, the species likes the rich, acid soils and deep shade of the ancient eastern forests. But there are several species that thrive in the more alkaline soils across the Midwest. Our goal is to expand the range of growing areas for some species and increase the overall diversity.
Trillium plant parts illustration from Trillium, by Fredrick W. Case and Roberta Case, Timber Press, Portland, Oregon, 1997.
Urban growth and development over the years has cleared the forests in many of the natural habitats of the species. Some species, like Trillium persistens, are extremely rare and considered endangered. Trillium are so beloved that they have appeared on two U.S. Postal Service stamps.
Come for an early spring walk to look for trillium and other wildflowers in the McDonald Woods. Or join a free guided McDonald Woods wildflower walk at 1 p.m. on Saturday, April 21, as part of the Garden’s new Unearth Science festival.
Marcia Glenn volunteers with Andrew Bunting and the Plant Collections team, and Lisa Hilgenberg in the Regenstein Fruit & Vegetable Garden. She has more than 30 years of experience in agriculture, international trade, government policy, and management, and has served on several boards. She has a bachelor’s degree and master’s degree in agricultural economics and is a master gardener.
