Autumn Blooms in the Bulb Garden

It’s now early fall and that means it’s time for Colchicum! Colchicum is a group of flowers also known as autumn crocuses, though they’re not related to the true crocus. Seventeen species and varieties of Colchicum grow in the Graham Bulb Garden. Flower colors range from white to magenta-violet, and include doubles and bicolors.

PHOTO: Colchicum cilicum.
Colchicum cilicum

Colchicum blooms are a great way to brighten up the early autumn landscape. They’re best grown in a groundcover or as an underplanting for taller bulbs such as lilies (Lilium sp.). The spring foliage can be rather large and hosta-like, making them sometimes difficult to pair with smaller spring-blooming bulbs such as Scilla, but it makes them perfect for hiding bare stems of tall plants in the summer while providing a jolt of color to your beds just before everything goes to sleep for the fall.

PHOTO: Colchicum 'Antares'.
Colchicum ‘Antares’

PHOTO: Colchicum x agrippinum.
Colchicum × agrippinum

In addition to the crocuses, dahlias and lilies are still bursting forth with color, like jewels in the September garden. The cooler temperatures help create richer colors in the dahlias, and longer-lasting blooms, while their large size provides a contrast with the dainty blooms more typical of fall bulbs. We’re still seeing the final blooms of Lilium speciosum ‘Uchida’ as well. This lily is notable for being the latest-blooming lily in our climate. These plants started blooming in early September and are still holding on. Due to their late blooming nature, these beauties must be planted in the spring in a well-drained but fertile area. 

PHOTO: Lilium speciosum 'Uchida'.
Lilium speciosum ‘Uchida’

PHOTO: Dahlia 'Bahama Mama'.
Dahlia ‘Bahama Mama’

PHOTO: Dahlia 'Diva' and Salvia guaranitica 'Argentina Skies'.
Dahlia ‘Diva’ and Salvia guaranitica ‘Argentina Skies’

PHOTO: Dahlia 'Jitterbug'.
Dahlia ‘Jitterbug’

While these might be the last blooms of the season in the Bulb Garden, this certainly isn’t the end of interesting things happening in the Chicago Botanic Garden. Fall foliage color will be peaking soon, and winter holds its own interest in the colors of berries, dogwood stems, and the exfoliating bark of the birches against snow’s white blanket.

©2014 Chicago Botanic Garden and my.chicagobotanic.org

Blooms with Boyce: The Orchid Show

We learned about some of the more unusual orchids featured in the Orchid Show (purchase tickets here) when we toured with Boyce Tankersley, director of living plant documentation.

PHOTO: Dendrobium Comet King 'Akatsuki' orchid.
Dendrobium Comet King ‘Akatsuki’

Boyce told us we have 183 taxa of orchids in our plant collections and 53 of those are straight species found in the wild. Of course, none of our orchids are wild-collected because that does damage to the species, so the orchids we acquire are propagated through tissue culture. We display the orchids that do best in our greenhouse growing conditions, and most of those do best in the Tropical Greenhouse.

Some of the orchids Boyce shows us in the video below are Vandas, which are native to the Philippines and other islands in Southeast Asia.

Boyce shared his love of Dendrobiums and revealed a goal to visit an area of the Himalaya Mountains where they cover the oak trees. But watch out: Boyce warns us of leeches in the area! (Don’t worry, we don’t have those in our greenhouses!)

Finally, we examined an interesting ground orchid, Phaius tankervilliae ‘Rabin’s Raven’, which is growing very well in our greenhouse conditions.

Vanda Orchid
Vanda manuvadee
Nun orchid
Phaius tankervilliae ‘Rabin’s Raven’

Click on the video link above or watch on YouTube to get the full tour!


©2014 Chicago Botanic Garden and my.chicagobotanic.org

Darwin’s Orchid and the Wardian Case

There’s something very special about this orchid. Can you tell what it is?

PHOTO: Closeup of Angraecum sesquipedale bloom.
A native of Madagascar, Angraecum sesquipedale is an epiphyte that prefers the drier branches and trunks of trees as a host.

 

The nectar of this orchid resides almost entirely at the tip of the orchid's spur.
The nectar of this orchid resides almost entirely at the tip of the orchid’s spur.

If you guessed that it was the long tubular structure coming from the back of the flower, you are right! That spur contains energy-packed nectar and is the reason this plant has a place in history.

Discovery

Angraecum sesquipedale was first described in 1822 by French botanist Louis-Marie Aubert du Petit-Thouars and would be shrouded in mystery for decades after. It arrived in the United Kingdom 33 years later.

ILLUSTRATION: an illustrated plate of Angraecum sesquipedale from 1822.
An illustration of Angraecum sesquipedale from Histoire particulière des plantes orchidées recueillies sur les trois îles australes D’Afrique de France, de Bourbon et de Madagascar (1822) .

At the time  this orchid was discovered, transporting plants from one continent to another was extremely difficult and often unreasonable. The long sea journey, combined with polluted conditions in industrialized cities, made it difficult to collect and maintain specimen plants. This would all soon change.

It was in 1829 that Nathaniel Bagshaw Ward discovered the mechanism that revolutionized horticulture and botany forever. 

The Wardian Case

Nathaniel Bagshaw Ward was an English doctor who spent most of his life in eighteenth-century London. In his youth, he perused the writings of Linnaeus and spent some time in Jamaica, which fostered his love of entomology and botany. As an adult, Ward was inspired to create a wall of ferns and mosses in his own yard, but failed due to the polluted air of East London. He was distraught.

In the summer of 1829, Ward took a glass jar and placed a hawkmoth chrysalis inside, atop a bed of moist leaf mold. Ward regularly checked on the progress of the moth, finding that before it hatched, grasses and a fern emerged from the leaf mold. Ward observed that the glass jar retained moisture because as it warmed up, water evaporated, condensed on the glass, and returned to the base of the jar, never escaping. With this success he repeated his experiment and, to his delight, found that he could keep plants growing within the chamber for years. His discovery brought about the invention of the Wardian case, the predecessor to the modern terrarium. He wrote extensively about this in his book, On the Growth of Plants in Closely Glazed Cases. Soon the Wardian case became a popular feature of the parlor in Victorian society. These parlor versions, both tabletop and freestanding forms, often held one or more plants and could be rather ornate.

PHOTO: A large Wardian case, made of steel and glass—an individual greenhouse for an orchid.
One of four Wardian cases appearing in our Orchid Show this year. Wardian cases like this one could be found in parlors of wealthy Victorians.

In 1843, the Wardian case was used for the first time to bring plants from China by sea. The director of the Royal Botanic Gardens, Kew, observed that in 15 years, the Wardian case brought six times as many plants as had been imported in the last century. If you do the math, that means it made importing plants almost 40 times as efficient as regular ocean travel! This was of particular use to collectors like James Bateman, a wealthy landowner who sponsored several plant exploration trips through the Royal Horticultural Society. One such trip would bring several rare Angraecum sesquipedale from Madagascar to England, and in 1862, this plant would find its way to one of the prominent figures in history.

Charles Darwin

By 1862, Charles Darwin had already become a prominent figure internationally. Having published On the Origin of Species three years earlier, Darwin was already the subject of scrutiny by religious groups and scientists who disagreed with his theories on evolution and natural selection. In this same year that he received a number of orchids from Bateman, Darwin published his book The Various Contrivances by Which Orchids are Fertilised by Insects, which proposed that Angraecum sesquipedale must be pollinated by a “huge moth with a wonderfully long proboscis” (or straw-like tongue). He proposed that it might be a Sphingidae moth since these are typically large. No such moth was known to exist on Madagascar.

Though largely overlooked by the public, his proposal became a subject of controversy, particularly in the religious community. Critics attributed any existence of such a creature to be by divine will and not natural selection; most mocked the possibility of such a moth existing. Others viewed his prediction with skepticism since only smaller moths had been discovered in Madagascar.

PHOTO: Morgan's sphinx moth, with its 30-centimeter tongue unrolled to show its length.
Morgan’s Sphinx moth, the predicted pollinator. Photo by Esculapio (Own work) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons

In 1903, 21 years following Darwin’s death, a subspecies of moth known as Xanthopan morgani praedicta, Morgan’s Sphinx moth, was found in Madagascar. This moth has a wingspan of 5 to 6 inches and a proboscis of 10 to 12 inches long. The subspecies name, praedicta, was intended as an homage to Darwin’s prediction that such an insect existed.

Angraecum sesquipedale, frequently referred to as Darwin’s Orchid, is currently being displayed in the Greenhouse Gallery of the Orchid Show (purchase tickets here) this year.

©2014 Chicago Botanic Garden and my.chicagobotanic.org

Living Fossils

I have been waiting weeks for my favorite moment in fall. It’s almost here! My ginkgo is turning golden and is getting ready to drop its leaves!

It might not be an exciting prospect for some people but the fall leaf drop of Ginkgo biloba is something I find amazing and wonderful. Before I get into why, let me tell you about this fantastic tree.

PHOTO: Ginkgo tree in spring and summer green color.
Also known as maidenhair tree, Ginkgo biloba has unusual leaves in that they do not have a branching network of veins; single veins run from the base of the leaf in a straight line to the edge.

Ginkgo biloba is a living fossil—fossils of Ginkgo biloba date back 270 million years, predating even the dinosaurs. This tree is truly durable and long lasting. They make excellent street trees, tolerating restricted soil space and pollution. Several even managed to survive the detonation of the atomic bomb over Hiroshima, Japan!

PHOTO: Ginkgo trees planted along a street.
A row of ginkgo trees planted along a street demonstrates the difference in growth habits.

Though ginkgo tree habits tend to vary between cultivars, they can grow anywhere from 50-100 feet high and 30-40 feet in diameter. When left to grow naturally, these trees will grow slowly, but growth can be accelerated with the help of fertilizer and watering. Young ginkgoes can often be very open and awkward-looking when left unpruned, and this is clearly visible with some street trees. Their habit, however, will improve with age as these young, long branches will become massive and reminiscent of old oaks over time.

Ginkgoes can be male or female, and identification is easiest at this time of year. Your nose can tell you if a ginkgo is male or female before you even see it. The female typically produces an abundance of fruit with a bad odor. In fact, the University of Illinois has a female ginkgo tree near the center of campus where students frequently walk, and it is not uncommon to see people checking their shoes, thinking they “stepped in something.” This fruit frequently makes a mess on lawns, paths, and sidewalks. That is why males are usually preferred for landscapes.

PHOTO: Gingko fruit and leaves on the grass underneath a tree.
Yes, they are edible, but the fruits of the female ginkgo tree have a distinctive, unfriendly smell. Female trees are often single plantings, rather than a series of trees.

In spite of the fruit odor, and beyond their ornamental value, some research suggests that the leaves can be used to improve memory and concentration. The leaves also increase the body’s production of norepinephrine, which can increase heart rate. The seeds of the female tree can also be used in cooking and are sometimes considered an aphrodisiac. If you are interested in picking the fruit, however, make sure to pick fallen fruit and wear gloves, because some people will have an allergic reaction from contact with the fleshy coating.

My favorite thing about ginkgoes, however, is their dramatic fall color and leaf drop. The leaves of ginkgo turn a beautiful golden yellow that rivals the fall color of birches. Beyond their fall color, the real drama happens after the first few golden leaves fall. After this, you can expect the rest to fall within the next 48-72 hours, carpeting the ground beneath it in golden yellow leaves.

PHOTO: Ginkgo tree in fall color.
A ginkgo tree in full fall glory. Male trees bear catkins in early spring; female trees flower, but very inconspicuously.

If you’re thinking about growing a ginkgo, it is important to always consult with a nursery about the varieties they have, and the gender of the trees. Buying an unnamed cultivar grown from seed is a big risk if you don’t want to be cleaning up the fruit later. (It takes 20-50 years for a ginkgo to produce fruit, so you may suffer the consequences if you don’t attend to the details when you make your initial purchase.)

As part of our specialized collection, the Chicago Botanic Garden has 28 different varieties of Ginkgo biloba, all of which can be located via our website and GardenGuide plant finder app.

I hope you can find your way to the Garden and check out all our wonderful ginkgoes!


©2013 Chicago Botanic Garden and my.chicagobotanic.org