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Contents tagged with horticulture

  • Carnivorous Plants of the Chicago Region

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    Tags: horticulture, Biology, carnivorous plants, plants, wetlands, bogs, marsh

    Created: 6/26/2013      Updated: 8/9/2016

    People often think of carnivorous plants as being tropical monstrosities, but many species make their homes in cold climates, and some can even be found in the Chicago region. The Museum's Biology Department took a trip several years ago to the Indiana Dunes' Pinhook Bog (open only to guided tours due to the fragility of the ecosystem) where we saw sundews, pitcher plants, and bladderworts--all species that make up for the low-nutrient peat moss they grow in by digesting insects. Combined with the rare orchids, blueberry-lined walkways, and the fact that the ground moves when you walk on it, it was one of my favorite daytrips. Volo Bog, north of Chicago, is home to such strange plants as well.

    Sarracenia purpurea
    Sarracenia purpurea

    While the Venus Flytrap (Dionaea muscipula) is the most iconic carnivorous plant outside of Super Mario Brothers and Little Shop of Horrors, our local meat-eating flora have plenty to offer. Pitcher plants (Sarracenia purpurea) have leaves that form a tube that collects rainwater. The attractive red coloration draws curious creatures to the rim of the "pitcher." Occasionally an insect will fall down the slippery slopes into the pool of rainwater and be trapped, and shortly thereafter digested. But since plants lack teeth, the plant has to hire someone else to chew its food. It is said that "If you build it, they will come," and a host of invertebrates make their home in the water of the pitcher plant, forming a mini-ecosystem inside the leaves of one plant. The top predator is usually the larva of the Pitcher Plant Mosquito (Wyeomyia smithii), one of several animals which lives only inside pitcher plant puddles, and nowhere else. Please don't think we should fog the bogs, though; the pitcher plant mosquito doesn't go for people. Eventually bits of the prey are chewed, shredded, digested, and excreted by enough little bugs, bacteria, and other critters that nutrients from the victim's body become usable by the plant.

    Sarracenia purpurea
    Sarracenia purpurea

    Drosera rotundifolia, the Downy Sundew, takes a different tactic. Its leaves are covered with red, tentacle-like protrusions, and coated in a sticky, sugary substance.  When prey come investigating they get stuck. The tentacles then curl up around the insect, and the plant begins to exude enzymes to extract precious, nitrogen-containing compounds that are otherwise hard to come by in the sundew’s habitat.  This is because in bogs, the high acidity of the peat moss and water inhibit the breakdown of organic matter, so nutrients remain locked away instead of cycling through the ecosystem as they might in more garden-variety soils. Many Drosera species have become so adapted to their conditions that they completely lack the enzyme that enables other plants to absorb nitrogen from their roots.

    Drosera rotundifolia
    Drosera rotundifolia

    While our collection is small, the Museum does maintain several living examples of carnivorous plants in our Mysteries of the Marsh exhibit. As these are wetland plants, they are members of some of the most imperiled ecosystems in our region, and throughout the world. While we are tempted to think of plants as basically immobile, passive denizens of our world, carnivorous plants are some of the most obvious examples of the incredibly active role plants take in nature. Stop by and see ours, but more importantly make sure to get out into the wild, visit our protected wetlands, and spot these fantastic plants in their native environments. You won't regret it.

    Andrew Wunschel
    Assistant Horticulturist

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  • The Osage Orange

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    Tags: osage orange, hedges, midwest history, chicago history, regional history, bow, osage nation, plants, horticulture

    Created: 5/23/2013      Updated: 8/10/2016

    The first question I ask of any plant is “Can I eat it?". But there are plenty of other fascinating stories waiting to be told. Take for instance the unruly-looking and inedible* Osage-orange (Maclura pomifera).  Its closest regional relative is the mulberry (Morus sp.) but most of the Moraceae family is more tropical—figs and jackfruits, for example. Its softball-sized fruits are hard, dense, only vaguely resemble oranges, and aren’t related to them at all. It takes its common name from the Osage Nation, a tribe which used the tree for tools, clubs, and most importantly, bows. There are records of a well-made Osage-orange bow being worth a horse and blanket as an even trade, meaning the people controlling the supply of the trees could make quite a tidy living as, effectively, arms traders. There seem to have been multiple wars fought over the land where the trees grew, and the Osage Nation was known to send parties hundreds of miles to harvest from their favorite stands. Even the Blackfoot tribe in now Montana used bows of this wood, nearly 2000 miles from where it grew.

    At the time of European colonization, the range of the Osage-orange was confined to river bottoms in a relatively small area of what became Texas, Oklahoma, and Arkansas. Why this is so is a subject of some speculation. Generally when a tree produces such a large fruit it is because some large critter loves to eat that fruit, and the seeds get dispersed when the odd few make it through the digestive tract unharmed and germinate. But nothing really seems to like the Osage-orange fruit. Squirrels will tear them apart to get to the seeds, but they grind the seeds to pulp and destroy them in the process. One theory is that animals now extinct on the continent were the primary distributor of the fruit, perhaps mastodons, early horse-like animals, or some sort of (I’m not kidding) giant sloth. With their decline, possibly due to overhunting, came the diminishing range of the tree, and it is possible it could have gone extinct without Native Americans propagating it for their uses.

    • Osage Tree
    • Osage Seed Ball

    Lewis and Clark sent some cuttings to President Jefferson as part of their first shipment of samples. They got them from a guy who said they came from an Osage Indian village, and the common name was a done deal--though they called them Osage-apples at first. European settlers had little to no use for longbows, but high on their wish list was fencing or hedges to ‘civilize’ the prairies. (It had been common practice in much of Europe to mark field boundaries with hedges, which can provide harvestable yields, contain livestock, reduce wind, and provide habitat for wildlife.) Osage-orange was found incredibly suitable to this task, because if densely planted it provided a fence “horse high, bull strong, and pig tight,” in the words of one early promoter. This is why many people from rural backgrounds, myself included, first learn this tree as the “Hedge-apple.”  (As an aside, other plants brought from overseas to serve this purpose include buckthorn (Rhamnus cathartica) and multiflora rose (Rosa multiflora), both of which have become destructive invasive species.)

    • Osage Hedge Trimmed
    • Osage Fencepost

    Eventually the hedge fell out of fashion because of a fabulous new invention: barbed wire.  Farmers decided they’d rather have dead fences than living ones, since time spent pruning is time not plowing.  They were pleased I’m sure to learn that Osage-orange is one of the most fungal- and rot-resistant woods in the world, and immune to termites, giving farmers another incentive to keep the trees around for their value as fencepost material (above right). And after the Dustbowl, millions of the trees were planted in a 100-mile wide strip from North Dakota to Texas as part of FDR’s Great Plains Shelterbelt program, eventually run by the WPA. This program is to date the largest US government program aimed at tackling an environmental problem. Eventually the trees became established or reestablished in all of the lower 48 states.

    You can still see remnant Osage-orange windbreaks marking field edges in the Chicagoland region and beyond. Some people recognize the altogether silly fruits, and occasionally remember hearing that people put them around the house to repel spiders back in The Before Time. Some folks still heat their homes with wood, and may know that it provides the highest BTU value of any wood in North America. But few people are aware of the role this one plant species has played in the history of this country, the many nations that came before it, and perhaps the continent before humans ever arrived. 

    Not a bad story for being inedible.

    Andrew Wunschel
    Assistant Horticulturist

    *There are reports you could go through a lot of effort to get the seeds out and eat them, with no ill effects, but to me “edible” means “worth eating.”

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  • Integrated Pest Management in the Butterfly Haven

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    Tags: pest management, butterfly haven, horticulture, insects

    Created: 1/15/2013      Updated: 8/10/2016

    I'll be honest with you, folks. There's just no way I can keep every greenhouse pest out of the Judy Istock Butterfly Haven. And you want to know something else? I don't particularly intend to.

    Now I'm not rolling out the red carpet for aphids here. At least not compared to the hero's welcome they get just by us stocking the Haven with all their favorite foods and a perfect breeding climate. If they were easy to keep out, they wouldn’t be called pests. Aphids, whiteflies, mealybugs, and scale insects can lay waste to thousands of dollars' worth of plants in no time, and then all we'd have is hungry butterflies and some sticks covered in bug poo.  

    Mealybug
    Mealybug Destroyers

    I could run around in the off-hours spraying chemicals. I don't because 1. Toddlers (et al) will put anything, including leaves coated in poison, directly into their mouths and 2. Butterflies, being insects, react unfavorably to insecticides. Also, I'd have to get here even earlier in the morning. 

    But more important than my alarm clock is the fact that we, as an institution, have adopted Integrated Pest Management (IPM) as our strategy for all pests. One part of IPM means using the least harmful means of control first. That would be prevention most of the time. I check plants for infestations before I plant them in the Haven. I monitor the plants already there to catch outbreaks at early levels, and then a little soapy water works miracles. But the true secret, the one that has me smugly unconcerned while hordes of mealybugs roam the streets, is that every now and then I release MORE bugs into the Haven.

    We order the workhorses of the Butterfly Haven from Beneficial Insectary in Redding, CA. Ladybugs (Hippodamia convergens) devour most soft-bodied plant pests, and do so as adults and as larvae.  This is also true for the similar-looking Cryptolaemus montrouzieri, which goes by the more pronounceable and colorful common name ‘mealybug destroyer.’ I also release three wasps into the Butterfly Haven--all of them completely harmless to humans. In fact, they are all smaller than the stinger of the wasps commonly associated with fear and pain. Being so small I guess they are not worthy of cool common names, but they answer to Aphidius colemani, Aphytis melinus, and Encarsia formosa and they parasitize aphids, scale, and whiteflies respectively. Parasitic wasps lay their eggs inside living hosts, sometimes paralyzing them first, and let their newly-hatched young eat their way out. Some people think that's gruesome, some think it's awesome, some think it's both. 

    Ladybug
    Our workhorse, the Ladybug

    Notice how I mention these helpers as adults and as larvae. If I were somehow, magically, able to remove every single 'bad bug' from the Haven, my beneficial buddies would have no food, and therefore couldn't breed and maintain a population. One aphid or scale (both of which can reproduce asexually, which is far creepier to me than the parasitic wasp thing) could turn into millions nearly overnight.  Instead we aim to keep the pests at an ‘acceptable’ level, which is another tenet of IPM. Then our beneficial insects have more likelihood of breeding and remaining in the Haven to greet incoming pests with something a little less like paradise.

    To them, that is. All this goes on at the smallest limits of human perception.  At scales more in line with our everyday experience, the Haven remains the tranquil sanctuary we have come to expect. There might be an aphid or two in there, but don't worry. I'm hardly working on it.

    Andrew Wunschel
    Assistant Horticulturist

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  • Wherefore the fall that makes fall, fall?

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    Tags: trees, autumn, botany, horticulture, grounds

    Created: 10/8/2012      Updated: 8/10/2016

    The last, tremulous notes of the ice cream truck have faded into the distance. Sales of fun-sized candy bars are spiking. And all across this great nation, people are attaching their egos to teams of large, colorfully outfitted men battling over oblong balls. Yes, fall is here, and leaves are raining to the ground like opponents’ home runs onto the bleachers of Wrigley Field.  But why? Why would otherwise perfectly reasonable trees decide to shamelessly expose their naked limbs? (In front of the saplings, no less!)

    Fallen leaves on museum grounds

    Thanks, guys. You know I'm gonna have to rake that, right?

    Well, winter is hard on us all. For plants, the main problem is water, which, like most people, becomes sedentary and expands during cold weather. Sedentary water (by which I mean ice and snow) can’t be absorbed by a plant’s roots. So when the ground is frozen, water lost through its leaves can’t be replaced.  Most plants in our area avoid the problem by stripping bare.

    Tree with fall colors

    As for expansion, water is quite odd in that it becomes less dense when it freezes, so the same amount of water takes up more space when it becomes ice. This is a big deal for plants, since it causes their cells to quite literally explode as the water inside them swells. Try freezing a salad and you’ll know what I mean.

    So instead of risking death by dehydration or cell destruction, a clever tree ditches its leaves for the winter. But, you say, ever the contrarian, what about evergreens? Well, your average pine or spruce has small leaves with thick 'skin' to slow water loss. And it's quite industrious, churning out resins and antifreeze compounds to prevent cell damage. Deciduous (leaf-losing) trees can't be bothered to spend as much energy on such nonsense. What antifreeze they do get around to manufacturing is concentrated in their buds in preparation for spring.

    Tree with fall colors

    All this hard work gives evergreens a competitive advantage in early spring, when temperatures are warm enough for efficient photosynthesis. Deciduous trees can’t get moving until they stop hitting the snooze button and get to work cranking out leaves, while Joe Spruce is already soaking up the vernal sun and adding inches. The tables turn in summer, when the larger leaves of deciduous trees allow them to collect more light and grow faster than our work-a-day friend Mr. Spruce. These differing strategies are one reason evergreens dominate the landscape of northern latitudes. Short summers don’t allow those deciduous layabouts enough time to catch up.  

    Seth Harper - Museum Horticulturist

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