Archives For what’s in bloom

“Titan Tim” Pollak here, with today’s update on Spike, our first-ever corpse flower.

PHOTO: The corm of an Amorphophallus titanum: after a dozen or so years, it's large enough to produce a bloom!

The corm of an Amorphophallus titanum: after a dozen or so years, it’s large enough to produce a bloom!

Spike just keeps on growing at the Semitropical Greenhouse, and visitors are loving it. As they learn more about the coming bloom from the docents posted there, one of the most frequently ask questions is, “How could you tell this time that Spike was a flower?”

How could we tell that Spike was going to be a flower? It’s tricky. Even the most experienced botanists have a hard time determining whether a titan arum shoot is a flower or a leaf at first. But soon enough, the clues start to add up.

PHOTO: An Amorphophallus titanum shoot to the right of a leaf stalk provides comparison for determining the slight bulge which could mean a flower bud.

An Amorphophallus titanum shoot to the right of a leaf stalk provides comparison for determining the slight bulge, which could mean a flower bud.

PHOTO: The emerging Amorphophallus titanum plant looks leafy, unlike the smooth spadix which emerges from a flower bud.

The emerging Amorphophallus titanum plant looks leafy, unlike the smooth spadix that emerges from a flower bud.

  1. Spike is 12 years old. We know from other botanic gardens and conservatories that titan arums take a decade or more to send up their first flower shoot. We’ve been tending to this corm for about 12 years, so the timing was right.
  2. Is the corm big enough? The smaller the corm, the less power it has stored to send up the titan’s huge flower. This corm is about the size of a beach ball—definitely an appropriate size for flowering.
  3. A bulge at the base. It’s subtle, but a slight swelling at the base of the newly emerged shoot signaled something different than a leaf.
  4. A little off center. At 18 to 20 inches tall, we noticed a telltale sign: the tip of the shoot was off-center. While leaf shoots are true to center, we knew that a flower shoot powers up in a slightly different way. Again: it’s subtle but telling!
  5. Horticultural intuition. Both Deb Moore—our indoor floriculturist who tends to our nine titan arums—and I felt that the overall look of the shoot was different than what we’d experienced before with shoots that become a leaf. (While the titan’s non-bloom form may look like a stalk with multiple leaves, it is actually a single, giant leaf!) Like every gardener, you develop a sense for what’s “normal” and what’s not when it comes to your plants. We both thought that this shoot was somehow different, and it was!

PHOTO: While these may look like branches and leaves, each of these Amorphophallus titanum are actually single-leaf plants.

While these may look like branches and leaves, each of these Amorphophallus titanum are actually single-leaf plants.

Our final “sign” was to ask the experienced titan growers from other institutions. We called upon the folks at the Huntington Library, Art Collections, and Botanical Gardens in San Marino, California; Smithsonian Gardens in Washington, D.C.; Phipps Conservatory and Botanical Gardens in Pittsburgh, Pennsylvania; and Missouri Botanical Garden in St. Louis, Missouri, for their opinions and expertise. Their final confirmations gave us the thumbs up to go public with the big news that Spike would soon blast into bloom!

Like first-time parents, we are learning as we go. I can’t tell you how excited we all are in the production greenhouses—it’s a thrill to watch a plant that you’ve tended for so long finally get ready to flower! Visitors’ anticipation is rubbing off on us, too—we’ll be standing right next to you as the titan arum heads into its big night of bloom!

I’ll keep you posted…


©2015 Chicago Botanic Garden and my.chicagobotanic.org

Is Spike Blooming Yet?

3 Ways to Tell

Tim Pollak —  August 11, 2015 — 14 Comments

Spike is about halfway up the expected height chart (we’re thinking 6 to 7 feet, ultimately), so the big question now is, “How do you know when it’s going to bloom?”

PHOTO: Taken yesterday (August 11, 2015), our titan arum reaches the "halfway" point in its growth chart.

Taken yesterday (August 11, 2015), our titan arum reaches the “halfway” point in its growth chart.

Titan arums don’t give up their secrets easily. Just as it’s difficult to distinguish a leaf bud from a flower bud (we talked about that in our last blog post), it’s hard to know when the bloom cycle has actually begun.

Once again, our titan-experienced friends at other botanic gardens and conservatories have offered up a few helpful hints.

PHOTO: Closeup of spathe loosening from spadix of Amorphophallus titanum at the Sydney Royal Botanic Gardens 2 days before opening (in 2008).

A close-up shows the spathe loosening from spadix of Amorphophallus titanum at the Sydney Royal Botanic Garden two days before opening (in 2008).

  1. Growth slows. Spike is powering up 4 to 6 inches per day. As a titan gets ready to open, that growth rate slows noticeably. It’s a rather obvious clue, but by the time the plant is 6 or 7 feet tall, you start to marvel at the overall size and forget about incremental daily growth. We’re posting our measurements daily here, so heads up when you notice the numbers getting smaller.
  2. Bracts fall. What? Look down at the base of the spathe. Two modified leaves called bracts encircle the spathe. As Spike gets taller, these protective bracts shrivel and dry up. About a day before full bloom, they fall off—first one, then the other. That’s a sure sign that bloom is about to happen.
  3. The spathe loosens. Tightly wound around the towering spadix as it shoots up, the frilly leaf called a spathe starts to loosen its grip as bloom time nears, revealing the crazy-beautiful maroon color inside.

So those are the clues we’re watching for—now you can watch for them, too! How long will it be before the big night? I’ll keep you posted…


©2015 Chicago Botanic Garden and my.chicagobotanic.org

What’s that smell?

Tim Pollak —  August 6, 2015 — 2 Comments

In gardening, as in life, patience is a virtue. Twelve years ago, the Garden embarked on a mission to bring a rock star of the plant world to the Chicago Botanic Garden. The titan arum (Amorphophallus titanum), also known as the corpse flower, is the largest flowering structure in the world. When it blooms, it puts on a show like no other. 

Huge. Rotten. Rare. Watch our video on YouTube of Spike moving to his display location.

Why the big stink? During the peak of its bloom, which could happen in the next two weeks, the titan arum will emit a foul odor that pollinators can detect from about an acre away. Who would want to miss that?

PHOTO: Checking in on the progress of the titan arum, or corpse flower (Amorphophallus titanum).

Checking in on the progress of the titan arum, or corpse flower (Amorphophallus titanum)

Native to the rainforests of western Sumatra, Indonesia, the titan arum is distinguished by its large size, odd shape, and terrible stench (hence its common name, corpse flower). Plants bloom for a single day every seven to ten years, and it is nearly impossible to predict the day it will be at the peak of bloom. When those magical hours finally occur, the bloom unfurls into a dramatic, blood red “flower” with a nauseating stench that can be detected up to an acre away. It’s a once-in-a-lifetime experience. 

We have been cultivating nine of these mysterious plants behind the scenes in the production greenhouses, watching them grow foliage each year, and guessing what a flower might look like as it emerges.

Today we are so excited to be moving Spike to the Semitropical Greenhouse in the Regenstein Center. (We have named our titan arum Spike because when you grow a plant for 12 years, you start to think of it as a child.) Spike is growing several inches every day. We are so proud of Spike and are also thrilled he is the first titan arum to bloom in the Chicago area.

Come welcome Spike, and join the countdown to the big bloom! If you do, let us know what you think in comments here, via Twitter, Instagram, Facebook or Tumblr. Use the hashtag #CBGSpike and our handle @chicagobotanic


©2015 Chicago Botanic Garden and my.chicagobotanic.org

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! The Orchid Show closes March 16, 2014.


©2014 Chicago Botanic Garden and my.chicagobotanic.org

Heptacodium Miconioides, the Seven-Son Flower

A berm blog update

Dave Cantwell —  September 21, 2013 — 17 Comments
PHOTO: Image of bark

The gorgeous, exfoliating bark of Heptacodium miconioides looks stunning year-round.

Are you looking for a plant that offers some “wow” at the end of the season? That particular something that offers color, and maybe even more? Here’s something on steroids: Heptacodium miconioides.

This large shrub or small tree (15 to 20 feet tall on average), native and rare in the wild in China, was successfully reintroduced to western horticulture in the 1980s, and its popularity has come to span the globe for good reason: this is not just a brilliant autumn performer—it’s a year-round beauty! I suppose we can start the story when this ornamental shrub is dormant in the winter, with its striking exfoliating bark peeling off of nearly every branch in tan, cream, or light brown ribbons or patches, revealing the underlying tissue that has developed into a wash of many colors: vertical striations of creamy white, deep yellow, green, tan, bluish-green, olive green, brown, ochre, and even rust; more so as the plant ages. But that’s just the beginning of the show.

PHOTO: Heptacodium miconioides in flower

The Latin Heptacodium means “seven flowers,” hence its common name “seven-son flower”— though that’s just the average number of flowers on each shoot.

Heptacodium are among the first to sprout leaves in the spring, and their light green color is especially attractive. Should they break dormancy in an early thaw and the leaves succumb to a return of the cold, do not fret, because they’ll start over again. This plant likes to grow. Once the leaves fill in and the warm weather settles in, you’ll have a beautiful, irregularly umbrella-shaped, dense canopy of long, shiny, deep green leaves. And suckers. Be sure to catch them in late May and cut them off, as they can easily and rapidly form straight whip-like vertical branches that mess up the plan. You may even need to revisit the suckering scene in late summer, as it simmers down and readies to bloom.

Let your Heptacodium establish for a couple of seasons into a V-shaped, multistem plant, then select three to seven sturdy stems for the plant to stand on, and cut off the rest of the stems, including the suckers. (As we’ve mentioned, this plant likes to sucker. Profusely. Even if it gets run over by an off-road vehicle—and some of ours have—it will sucker back into a strong and proper plant in one or two seasons.) They really like to grow, and with few natural (nonautomotive) pests to disrupt their progress, they’re reliably hardy in the Chicago area’s Zone 5 climate.

PHOTO: Heptacodium miconioides in fruit

It looks like it’s blooming, but this is the fruiting stage. After pollination, the sepals elongate and change from green to dark pink, becoming part of the incredibly showy fruit.

In late summer the plants begin to set up for their flower display, developing whorls of buds at the tips of the branches; these structures form bracts of seven, hence its common name, “seven-son flower.” These open progressively, until the entire plant is covered in a cloud of tiny white blooms that smell somewhat like jasmine or alyssum—a sweet scent, to be sure. As amazing as this display can be, it changes even more. As the small dark fruits (or seeds, or berries) form, the white petals fade, and the corollas (flower petals) form sturdy calyces (a calyx is a specialized petal that wraps around the fruit) that color up into reds ranging from rose to nearly purple; some are even bluish in color, which can last as late as November, when the birds will find these treats and finish them off.

But wait—there’s even more! We’ve come full-circle back to the amazing winter display of that colorful, textural, exfoliating bark. With all of this to enjoy, seriously consider placing one (or more) of these beauties in a highly visible, year-round spot in your garden.


©2013 Chicago Botanic Garden and my.chicagobotanic.org