Woodcut Opens…

In the Woodcut video of artist Bryan Nash Gill at work, there’s a moment that made me gasp: as Gill peels back and lifts the paper from a tree’s cross section that he’s printing on, three dimensions seem suddenly distilled into two, revealing the internal life of the tree. That first peek is profoundly intimate and thought-provoking — check it out here.

It took 1,022 wood "cookies," 3 people, and 3 blisters to install the exhibition's title.
It took 1,022 wood “cookies,” three people, and three blisters to install the exhibition’s title.

Woodcut opened this weekend, with 25 of Gill’s prints presented in Joutras Gallery. Each of the AV (artist variation) prints is made by hand: Gill sands and burns a crosscut of a tree, inks it, then presses paper onto the ridges and edges of the surface. Most of the salvaged wood—fallen trees, a telephone pole, a tree hit by lightning—was collected near his Connecticut studio.

Yes, you can count the tree rings in his prints—but look closely and you’ll also see the good-weather years and the bad…the scars and damage from age and insects…the patterns of growth and the checks of disintegration. The largest print (nearly five feet high) documents an aged ash tree—an especially poignant piece for us at the Garden, where emerald ash borers were discovered in 2011, and where we expect to lose hundreds of native ash trees in the next few years.

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The theme of salvaged wood influenced the design of the exhibition itself. In the entry hall, the show’s title is formed by 1,022 wood “cookies” cut from branches pruned at the Garden, then glued into place on the wall. The gallery benches were made especially for this show, milled by an on-site sawyer on World Environment Day (June 3, 2012). After curing, the boards were sanded, sealed, and mounted as bench tops by our carpenters.

Now available at the Garden Shop, Woodcut: Prints by Brian Nash Gill
Now available at the Garden Shop,
Woodcut: Prints by Bryan Nash Gill.

Mr. Gill honors the Garden with a print called English Oak, on exhibit with the cross section of the tree from which it’s made. The tree stood as one of a pair along the outer road here; it was removed after it grew into its neighbor, threatening the health of both. (The second tree regained its vigor after the removal.) Gill made just 18 original prints from the cross section; the prints can be purchased at the Garden Shop

January is a splendid month to learn about trees at the Garden. In conjunction with Woodcut, the School of the Botanic Garden has a terrific lineup of tree-related classes and workshops.


©2013 Chicago Botanic Garden and my.chicagobotanic.org

Three Years of the Green Roof Garden…and Counting

It’s hard to believe that the Green Roof Garden has been in place for three full growing seasons already. Our horticultural and research staff is pleased to see how the green roof is growing and evolving as plants settle in and move around by rhizomes and reseeding. Despite the challenging weather of 2011 and 2012, the vast majority of the 240 taxa currently on the green roof have thrived. While our goal is to minimize the care and resources put into maintaining the roof, we had to give the plants supplemental water once in July 2011 and twice in June 2012 during periods of extreme heat and drought. Not surprisingly, the greatest stress was on plants in the shallow 4-inch-deep plots. But the great news is that plants rebounded quickly once they received the additional water.  

PHOTO: Aerial view of the PCSC green roof garden
The Plant Conservation Science Center Green Roof Garden

The Green Roof Garden contains a mixture of plants that are commonly grown on green roofs and other taxa that are uncommon or untested for this use. The plant evaluation component is a particularly exciting aspect of our green roof—fully half of the 16,000 square feet is dedicated to testing a broad variety of new plants for green roof culture. In a way, the sky’s the limit on what we can try. In fact, we initiated a new trial of prickly pear cactus (Opuntia spp.) in 2012 to see how these succulents from the western U.S. perform next to our local species, Opuntia humifusa.

PHOTO: Common mountainmint (Pycnanthemum virginianum)
Common mountainmint (Pycnanthemum virginianum)

There have been many success stories on the roof, but here are just a few native plants that I’ve found particularly strong performers in 2012:

Common mountainmint (Pycnanthemum virginianum) is native to eastern North America and found in dry and moist prairies and calcareous fens in the Chicago region. Plants remained ornamental and healthy regardless of droughty conditions; it is growing in the semi-intensive 8-inch substrate depth. While stress caused lower leaves to drop, plants flowered well and maintained strongly upright habits at all times. Plants were 22 inches tall and 10 inches wide in 2012 and the small white flowers were in bloom from early July to late September. Bees, moths, wasps, and flies are frequent visitors on common mountainmint.

Although pitcher sage (Salvia azurea var. grandiflora) is an introduced plant in the Chicago region, it is native to dry prairies in Illinois. Pitcher sage features exceptional sky blue flowers from late summer to frost. A serendipitous planting of pitcher sage, stiff goldenrod (Solidago rigida), and big bluestem (Andropogon gerardii) made a spectacular show last year. We’re growing pitcher sage in extensive to semi-intensive plots so flowering stems ranged from 30 inches tall in the 4-inch plots to 56 inches tall in the 8-inch plots.

PHOTO: Pitcher's sage (Salvia azurea var. grandiflora)
Pitcher’s sage (Salvia azurea var. grandiflora)
PHOTO: Stiff goldenrod (Solidago rigida)
Stiff goldenrod (Solidago rigida)
PHOTO: Big bluestem (Andropogon gerardii)
Big bluestem (Andropogon gerardii)

Prairie dropseed (Sporobolus heterolepis) and the cultivar ‘Tara’ are being grown in the extensive to semi-intensive plots. Variable plant sizes, from 14 to 40 inches tall and 26 to 40 inches wide, were observed in the different plots. Leaves remained green throughout the growing season, even in droughty conditions, and turned a beautiful orange in autumn. The pungently fragrant flowers opened in August and remained effective for many weeks. Prairie dropseed is native to mesic and hill prairies in Illinois. ‘Tara’ is generally shorter than the species by about a foot and has darker green leaves and a vase-shaped habit.

PHOTO: Arrowleaf violet (Viola sagittata)
Arrowleaf violet (Viola sagittata)

Arrowleaf violet (Viola sagittata) naturally occurs in sandy old fields and dry prairies in the Chicago region, and is known to occur in sterile abandoned clay fields where the topsoil has been eroded off. Given its adaptability to poor soil conditions, arrowleaf violet was recommended for testing by Jim Steffen, one of the Garden’s ecologists. Arrowleaf violet bloomed from early April to early May and then again later in the summer. It is a generous re-seeder and has begun to pop up around the Green Roof Garden. Plants are grown in extensive to semi-intensive plots, but greater vigor has been noted in 6 inches of growing media than in 4 inches.


©2013 Chicago Botanic Garden and my.chicagobotanic.org

Play with Your Pine Cones

I was walking under some pine trees near the Learning Campus and I took a picture of the cones I found.

PHOTO: The ground under the pine tree is covered in dry, brown pine needles and cones that are open, closed and in between.
I found two different kinds of cones on the ground under the pine tree.

When I was young, I noticed there were two different kinds of cones — some solid cones like the three in the lower left corner of the picture, and others are more like the open, branched cones at the top. I thought the pine tree made two different kinds of cones. Actually, they are different forms of the same kind of cone. I will show you how this happens.

I took three cones that were the same size and shape. Then I soaked one cone in a bowl of water. 

PHOTO: Pictured here are three pine cones of similar size, shape, and color.
I started with three pine cones of the same kind, shape, and size.

 

PHOTO: One pine cone is floating in a white bowl full of water while the other two are resting on the right side of the bowl.
I placed one cone in a bowl of water. It slowly began to change.

 

PHOTO: One pine cone is in the white bowl, now almost fully closed after ten minutes, while the other two are dry and unchanged at the side.
After about ten minutes, the wet pine cone is almost completely closed, while the dry cones are still open.

 

PHOTO: A wet, closed cone is shown next to a dry open cone.
Wet cones are closed, dry cones are open, and that is why cones from the same tree come in different shapes.

Then I let the wet and dry cones sit on my desk overnight. Guess what happened. Try it yourself to get the answer! Go outside and find a pine, spruce, or other conifer tree. Bring pine cones from those trees inside and watch them over time as they adjust to the warm, dry conditions in your home. Put one in bowl of water and see what happens. Let it dry and see if it changes again. 

What is going on here?

Pine, spruce, Douglas-fir and other conifers are so named because they produce cones that bear their seed. When conditions are favorable for the seeds to fall and grow, the cones open and release them. The seeds have the best chance to survive when the air is dry and windy, so they can blow to a nice fertile spot away from the shade of the mother tree. When conditions are wet and not so good for a traveling seed, the cones close to protect them.

Though the cones I found under the tree had released their seeds a long time ago, they still responded to the moisture levels of the ground and air. These cones were in between being damp from the rain over the weekend and drying in the sun.

Pine cone history

By the way, all conifers belong to a group of plants called gymnosperms. This means they produce “naked seeds” — seeds that are not contained within a fruit. Conifers do not grow flowers. Before there were dinosaurs on the planet, all plants reproduced by either spores or naked seeds. The seeds of some conifers can take up to three years to mature. Flowering plants (angiosperms) have a much more rapid reproductive cycle. Some angiosperms flower and produce mature seed in just one week. Understanding how cones and flowers have evolved is what Dr. Pat Herendeen is trying to figure out from plant fossils.


©2013 Chicago Botanic Garden and my.chicagobotanic.org

A Winter Tour of The Greenhouses

We recently toured the Greenhouses with Boyce Tankersley, director of living plant documentation, to see what’s in bloom and take in the different climates visitors can enjoy.

In the Arid Greenhouse, we saw a number of species of aloe from South Africa just coming into bloom as well as cacti and succulents.

In the Tropical Greenhouse, we were surrounded by palms and cycads while we admired the many orchids in bloom. Tankersley pointed out the acanthus cultivar (Aphelandra sinclairiana ‘Panama Queen’) native to Panama and Costa Rica, as one of his favorites. 

PHOTO: Panama Queen acanthus (Aphelandra sinclairiana 'Panama Queen')

The Semitropical Greenhouse was filled with blooms like pinkball dombeya (Dombeya wallichii). Native to East Africa and Madagascar, the genus is a highly sought-after ornamental in USDA Zones 9 and warmer.

PHOTO: Pinkball dombeya (Dombeya wallichii)

One of the rarest plants in our collections is Deppea splendens. Native to the mountains of western Mexico, this plant is extinct in the wild.

PHOTO: Deppea splendens

Visit our What’s in Bloom highlight page each week — twice a week during the summer bloom season — to learn more about the different plants in bloom. Then, come out to see them in person for their fragrance and the humidity of the warmer greenhouse climates.


©2013 Chicago Botanic Garden and my.chicagobotanic.org

Updated: Snow Drought!

There’s no doubt: it’s a snow drought, and records are falling like…well, like snowflakes should be falling.

  • Wednesday we broke the record number of days without a 1-inch snowfall (319).
  • Last weekend we broke the 1940 record of 313 straight days with less than 1 inch of snow on the ground.
  • Just 1.3 inches of snow (more near the lake) has fallen to date, compared to the norm of 11 inches.

It made us wonder: what does a snow drought mean for your garden?

To find out, we talked with Boyce Tankersley, our director of living plant documentation.

What Snow Drought Can Do to Your Garden

It’s easy to give snow drought the brush-off  (no shoveling! no scraping! no wet feet!), but it can damage your plants and affect the soil in your garden. The following can happen in a drought:

1. Moisture loss accelerates. “It’s the combination of no snow cover plus cold winter wind that does the damage,” Tankersley explains. “When there’s no snow, plants act like a wick in the soil, so the wind not only dries out the trees and shrubs, but also the soil they’re planted in.”  

2. Soil compacts. In a normal year, it rains in November, so the moist ground freezes as temperatures drop. Ice crystals form in the soil. As winter progresses, snow piles up, preventing wind from reaching the frozen moisture in the ground. With spring thaws, ground ice melts, creating air pockets and naturally looser soil. In short, Tankersley says, “winter is good for gardens.” Without that rain/freeze/thaw cycle, air spaces can’t form in the soil, so it collapses and compacts, requiring mechanical tilling to loosen it up again.

3. Plants get stressed beyond capacity. In 2012, plants endured an early spring with a late frost, followed by summer and fall drought, and now, snow drought. There’s a real risk of winterkill—the term used when plants succumb to winter conditions. “Check trees and shrubs for buds in early May,” Tankersley suggests, “especially non-natives like Magnolia soulangeana, which is particularly susceptible to winterkill.” Even well-established, old trees can succumb—forever changing yards and neighborhoods.

What You Can Do to Help Your Garden

On mild days when temperatures are above freezing, Tankersley’s strategies for home gardeners include the following:

mulched tree

1. Mulch. Like a thick blanket, mulch holds in moisture and creates a layer of insulation for soil. Tankersley’s choice in his own yard? Oak leaf mulch. Why? “The leaves decay slowly, so they release nutrients into the soil over time.” Other options: chopped up plant material from your yard (non-diseased, please), or scattered straw. 

2. Add native plants in spring. Natives are already naturally adapted to outside-of-the-bell-curve extremes, with some sporting roots 15 to 20 feet deep. Compare that to a typical landscape plant with roots just 6 inches deep.


©2013 Chicago Botanic Garden and my.chicagobotanic.org