Archives For Jacob Burns

Autumn Asters

Jacob Burns —  September 26, 2017 — 1 Comment

The harbinger of fall, for many folks, is when asters finally bloom. Their flowers look like miniature daisies and come in shades of purple, blue, white, and occasionally pink. These cool tones allow autumnal hues of yellow, orange, and red to truly pop throughout the landscape. Aster blossoms twinkle across roadsides, meadows, woodland edges, and even home gardens. Interestingly, astéri is the Greek word for star.

White wood aster (Eurybia divaricata)

White wood aster among birch trunks near the Bernice E. Lavin Plant Evaluation Garden sets the perfect fall scene.

Hosts of pollinators favor asters. The late-season blooms provide vital sustenance for adult monarch butterflies during their annual migration to Mexico. Each flower contains plentiful sources of pollen and nectar, because the central disc is comprised of up to 300 tiny florets. After pollination, a disc will turn darker and reddish, informing other insects to keep moving. In the end, birds come to consume the seeds.

Asters belong to a huge family called Asteraceae, which also includes daisies, black-eyed Susans, and sunflowers. They are mainly native to North America and Eurasia. More than 600 species once made up the genus known as Aster. However, in the 1990s, taxonomists decided to divide New World species into ten other genera. The most common ones are Eurybia and Symphyotrichum. Few nurseries adopt these names and continue to list their plants under the genus Aster

Asters are easy to please with well-drained soil and adequate sunlight. Some even prefer shade. An assortment of heights (1 – 6 feet tall) allows them to shine in the front, middle, or back of the border. Powdery mildew is problematic for some, but you can always hide the unsightly lower stems among grasses or ferns. While pretty in nature, some asters just look scruffy in the garden. Selecting the right type is the key to a tidy look. The following asters perform best:

Jindai Tatarian aster (Aster tataricus 'Jindai')

Jindai Tatarian aster (Aster tataricus ‘Jindai’) can be found in the Lakeside Garden and on Evening Island at the Trellis Bridge.

White wood aster (Eurybia divaricata)

White wood aster (Eurybia divaricata) can be found in the Heritage Garden beds, throughout the Landscape and Bulb Gardens, in large groupings on Evening Island, and all around the Plant Science Center.

Jindai Tatarian aster (Aster tataricus ‘Jindai’) originates in Asia and has uniquely large and toothed foliage. From mid- to late fall, lavender-blue daisies appear in showy flat-topped clusters upon 3 – 4 foot tall stems. Best planted in the back of a bed with plenty of sun and space, its roots slowly spread into a weed smothering ground cover. Pair it with some equally tall and tough switchgrass (Panicum virgatum).

White wood aster (Eurybia divaricata) blooms for a long time, starting in late summer and lasting throughout fall. Clouds of starry white flowers are borne on 2-foot stems with heart-shaped leaves. It grows in woodlands of eastern North America where it spreads slowly by rhizomes and quickly from seed. Cut spent flower stems off if you do not want extra plants. Combines wonderfully with ferns, sedges, and shade-loving goldenrods like Solidago caesia or Solidago flexicaulis.

Avondale blue wood aster (Symphyotrichum cordifolium 'Avondale')

Avondale blue wood aster (Symphyotrichum cordifolium ‘Avondale’) can be found on Evening Island, just west of the carillon along the path.

October Skies aromatic aster (Symphyotrichum oblongifolium 'October Skies')

Find aromatic aster (Symphyotrichum oblongifolium ‘October Skies’) in the Landscape Garden, along the Lakeside Garden path, at McGinley Pavilion, on Evening Island near the Arch Bridge, and near the Plant Science Center.

Avondale blue wood aster (Symphyotrichum cordifolium ‘Avondale’) is an extra-floriferous selection of an eastern North American species found at forest edges. A plethora of attractive blue flowers begin in early fall on 2 – 3 foot stems. Grows well in either sun or shade, where it adds additional color to perennials like Japanese anemone (Anemone hupehensis), monkshood (Aconitum), and the yellow fall foliage of blue star (Amsonia hubrichtii).

October Skies aromatic aster (Symphyotrichum oblongifolium ‘October Skies’) is a great alternative to New England aster (S. novae-angliae), because it is less prone to powdery mildew. With full sun, it forms a compact 2- x 2-foot mound of nicely scented foliage. In autumn, hundreds of blue-purple flowers cover the plant. The species naturally occurs across the central and eastern United States. Try it with fountain grass (Pennisetum alopecuroides).

Frost aster (Symphyotrichum pilosum)

Frost aster (Symphyotrichum pilosum) overflows the center plantings of the Heritage Garden.

Frost aster, or hairy aster (Symphyotrichum pilosum) is a 3- x 3-foot, clump-forming plant with many branched and arching stems. In fall, it becomes loaded with little white daisies and creates a baby’s breath appearance among flowers like Japanese anemone (Anemone hupehensis). Frost aster is common in a variety of dry, sunny habitats in eastern North America. It spreads happily by seed, so if you have too many, cut off the spent flower stems before they develop any further.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

The fourth of July is upon us, and while many beautiful flowers can be found in patriotic shades of red and white, the color blue is very difficult to find at the Garden.

In fact, blue is a rare sight in the entire natural world. Less than ten percent of the plant kingdom features blue flowers, which is extraordinary, since pollinators don’t seem to have a problem with them. Scientists have been investigating the origins of blue flowers for a long time, and it was not until recently that they came up with a result.

Blue sea holly (Eryngium planum)

Blue sea holly (Eryngium planum)

Flower colors are based on pigments that include anthoxanthins and anthocyanins. Anthoxanthin colors contribute to yellow flower petals and are quite common in the plant world. Anthocyanin colors impart red, purple, and blue in blooms, but are found much less often in flora. For anthocyanin to steer blue, complex scenarios must occur. Most often, metal atoms and ions interact with the pigment to modify the color. In addition, they alter the pH of cellular fluids to be alkaline, while most organisms have an acid or neutral chemistry.

What is thought-provoking is that a red rose and a blue cornflower (Centurea cyanus) contain the same anthocyanin pigments. Cardinal flower (Lobelia cardinalis) and big blue lobelia (Lobelia siphilitica) are of the same genus, but one flower is red and the other is blue. It is the rare and complex modification of that pigment that contributes to the blue flower being blue. More surprising is that hybridizers have yet to develop a truly blue rose or carnation (without resorting to pigmenting water, which a plant takes up, changing the color of its bloom). 

Royal Aspirations larkspur (Delphinium elatum 'Royal Aspirations')

Royal aspirations larkspur (Delphinium elatum ‘Royal Aspirations’)

Lobelia (Lobelia erinus)

Lobelia (Lobelia erinus)

Pacific Giant Cameliard larkspur (Delphinium 'Cameliard')

Pacific Giant™ cameliard larkspur (Delphinium ‘Cameliard’)

Since blue is uncommon, visitors at the Garden should take extra time to enjoy the flowers in the English Walled Garden, where they will find containers full of adorable Felicia daisy (Felicia heterophylla ‘Forever Blue’) right beside sky-colored plants called southern star (Tweedia caerulea ‘Heaven Born’)—a member of the milkweed family. In addition, there are cool-hued drifts of Magadi™ electric blue lobelia (Lobelia erinus ‘KLELE10670’) weaving throughout several garden beds, as well as spilling out of containers.

Another area with a good deal of blue flowers is the Heritage Garden. In the plant family area, you will find intricate love-in-a-mist (Nigella damascena ‘Miss Jekyll’) blossoms mingling with wispy yet showy Siberian larkspur (Delphinium grandiflorum ‘Blue Butterfly’). And nearby, nile lily flowers (Agapanthus ‘Queen Anne’) explode like bright blue fireworks. And finally, in the geographic area, sea holly (Eryngium planum) creates a shiny and spiky blue accent.

(Agapanthus africanus 'Queen Anne')

Nile or African lily (Agapanthus africanus ‘Queen Anne’)

Love-in-a-Mist (Nigella damascena 'Miss Jekyll')

Love-in-a-mist (Nigella damascena ‘Miss Jekyll’)

Blue Butterfly larkspur (Delphinium grandiflorum 'Blue Butterfly')

Blue Butterfly larkspur (Delphinium grandiflorum ‘Blue Butterfly’)

While it is difficult to achieve blue pigments in plants, the ones that did are certainly successful in this world. The word “perseverance” comes to mind, which just so happens to be what the blue within the American flag represents. Anyone who has marveled at a field of Texas bluebonnets (Lupinus texensis) and witnessed the huge number of bees and butterflies working to gather its pollen would agree.

Southern star (Tweedia caerulea 'Heaven Born')

Southern star (Tweedia caerulea ‘Heaven Born’)

Flying Saucers morning glory (Ipomoea tricolor 'Flying Saucers')

Flying saucers morning glory (Ipomoea tricolor ‘Flying Saucers’)

Happy Fourth of July everyone!


©2017 Chicago Botanic Garden and my.chicagobotanic.org

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

Wolfsbane is a beautiful—and poisonous—fall-blooming perennial. It also has a colorful history associated with werewolves, vampires, and witches.

PHOTO: Werewolf gargoyle at the Cathédrale Notre-Dame de Moulins

Werewolf gargoyle at the Cathédrale Notre-Dame de Moulins

The plant has been a familiar plot element in horror movies, television shows, and novels. In the Harry Potter series, Remus Lupin, a tormented werewolf, drinks a potion of wolfsbane carefully concocted to control his transformations. As early as Dracula in 1931, wolfsbane casually replaced garlic as a repellent for vampires in film. Nevertheless, the correlation of wolfsbane with the supernatural predates Hollywood and familiar authors. 

In Greek myth, wolfsbane (Aconitum) originated from the toxic slobber of a three-headed dog named Cerberus, the scary canine guardian to the gates of Hell. In the Dark Ages, wolfsbane was said to be used by witches in spells and potions and was one of several ingredients for an ointment that, when applied to a broom, could facilitate flight. Stories also proclaimed that a sorceress who carried wolfsbane seeds wrapped in lizard skin could become invisible and witches who applied the poisonous sap to their flints and launched them at unsuspecting enemies.

One thing both Hollywood and horticulturists can agree on: wolfsbane is a potent plant. Ingesting wolfsbane is typically fatal. 

PHOTO: Arends azure monkshood/wolfsbane.

Arends azure monkshood (Aconitum carmichaelii ‘Arendsii’)

PHOTO: Lamarck monkshood/wolfsbane.

Lamarck monkshood (Aconitum lamarckii)

The plant belongs to a genus of highly poisonous perennials known as monkshood or aconite. They naturally grow in mountainous areas across the northern half of the globe and are also planted in gardens for their deep purple blooms, which continue flowering long after other perennials fade for the season. Ancient Greeks hunted wolves by poisoning their bait with this plant, which lead to the common name of wolfsbane.

PHOTO: Werewolf illustration circa 1512 by Lucas Cranach the Elder

Werewolf illustration circa 1512 by Lucas Cranach the Elder

While those hunting traditions were lost, the plant retained its common name into the Middle Ages, where wolves and werewolves were a genuine fear in Europe. Frightened folks turned to growing wolfsbane for their protection, as superstitions said that werewolves could be repelled by the plant, or even tamed by it. Others, however, believed that having contact with wolfsbane on a full moon could actually cause shape-shifting. Patients who suffered from lycanthropy (the delusion of being a wolf) were prescribed regular—and often lethal—doses of wolfsbane by their medieval doctors.

For gardeners, it is important to remember to always wear gloves while handling a deadly plant such as wolfsbane.

Find wolfsbane at the Garden with our Plantfinder or on the GardenGuide app. Remember to look—don’t touch!—its beautiful blooms. Happy Halloween!


©2016 Chicago Botanic Garden and my.chicagobotanic.org

It’s officially summer in Chicago, and you’ll start to notice a plethora of begonias, impatiens, marigolds, cannas, dahlias, and elephant ears, all planted for a temporary taste of the tropics.

If you’ve dreamed about creating an exotic vacation look at home, but wanted to reduce your yearly investment in annuals, consider pairing them with tropical-looking hardy perennials that come back yearly. The following additions will help give your garden that south Florida feel.

PHOTO: Hibiscus 'Midnight Marvel'

Hibiscus ‘Midnight Marvel’

Midnight Marvel hibiscus

You don’t have to live in Hawaii to grow hibiscus. There are actually two species native to Illinois. Several others occur in the southeastern states. These hardy plants emerge late in the spring, get quite large and shrubby, bloom their hearts out in late summer, and then retreat underground when winters comes along.

Midnight Marvel is a spectacular hybrid with very deep wine-colored foliage and dinner-plate-sized crimson flowers. Each flower lasts just a day a two, but are so plentiful that the show lasts for weeks, and hummingbirds love it. After each flower passes, the light green calyx tubes look pretty set against the dark leaves. Midnight Marvel reaches 4 to 5 feet tall, so is best placed at the back of the bed in a site with full sun.

PHOTO: Belamcanda chinensis 'Freckle Face'

Belamcanda chinensis ‘Freckle Face’

Freckle Face blackberry lily

Orange is a hot color, perfect for a tropical garden. The flowers of Freckle Face blackberry lily (Iris domestica ‘Freckle Face’) are a gorgeous carroty shade with many vivid red spots covering each petal. The blackberry portion of the name refers to shiny black seed clusters that pop out of the split open pods. Sprays of flowers bloom for several weeks in late summer on these 2-foot-tall plants.

Despite its name, this plant isn’t actually a lily at all, but resides in the iris family. The blue-green spiky leaves even resemble bearded iris foliage. Taxonomists very recently changed the name, so when searching online, you will most likely find it under Belamcanda chinensis ‘Freckle Face’.

PHOTO: Aralia cordata 'Sun King'

Aralia cordata ‘Sun King’

Sun King udo

Here’s a statuesque perennial for the part-sun area of your tropical garden. An enormous specimen, reaching 6 feet tall and 3 feet wide, Sun King udo is mistaken for a shrub, but is completely herbaceous. This is definitely a shade plant, but providing it with just a few hours of sun will really enhance the gold color of its foliage.

In summer, Sun King udo’s many umbels of greenish-white flowers are total bee magnets. By autumn, the spent flowers have changed into densely fruited clusters of wine red berries. The fruits are attractive, but best left for the birds, since they are not remotely tasty.

Shieldleaf rodgersflower

If you’ve got shade, consider mixing bold and tropical-looking foliage for a jungle effect. The perfect non-invasive perennial for this is shieldleaf rodgersflower. Formerly in the genus Rodgersia, Astilboides tabularis produces gigantic 2 to 3-foot-wide parasol-like leaves.

PHOTO: Astilboides tabularis

Astilboides tabularis

While the leaves are the most striking part, creamy-white astilbe-like flowers do sprout up through the dome of foliage in late June. With enough moisture, the foliage remains light green and attractive until autumn. This is not a plant for dry shade or windy spots, but perfect for moist, rich soil. For additional large leaves in the shade, try Ligularia dentata ‘Othello’, Hosta ‘Sum and Substance’, and Rodgersia.

PHOTO: Dryopteris goldiana

Dryopteris goldiana

Goldie’s fern

Tropical gardens are meant to invoke a relaxing vacation, and what is more cool and calm than ferns? Many gardeners grow ostrich fern, which is one of the largest and most tropical-looking spore producers in the Northern Hemisphere. However, ostrich fern can be a bit of a thug if space does not permit. Instead, try growing Goldie’s fern, which is a slow spreader and the largest species of Dryopteris in the United States. Under the best conditions, it will reach 4 feet tall and 3 feet wide. The fronds are a soothing shade of dark green and not golden as the name implies. (It is actually named after Scottish botanist John Goldie.)

The trick to getting the tropical look to work in your garden is to create a framework of dramatic, large-leaved perennials, and lacy, soothing ferns, then surround those with some hot red, orange, and yellow annuals. Top it off with some tiki torches, bamboo fencing, and a few lawn flamingos and you’ll have the perfect paradise for a hammock and mai tais!


©2016 Chicago Botanic Garden and my.chicagobotanic.org