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What is a Bog?


Bogs are acidic, peat-accumulating wetlands defined by three main characteristics:

  • Sky-Water: Rain & snow (rather than ground water and runoff) are the main water sources in true bogs. We refer to this as meteoric water as it comes from the sky.

  • Peat Soil: Peat is poorly decomposed dead plants (and probably a few dead animals). Peat accumulates due to lack of decomposition caused by acids and low oxygen in bogs.

  • Unique Plants: A variety of plant adaptations have evolved to deal with the rigors of acid and poor nutrient availability.

What's with the Sky Water?

Sky water is slightly acidic. When water percolates through the ground, it is buffered by the rocks. Without a ground water source, acids build up in bogs. Without an inlet or outlet, the water in bogs becomes stagnant. Hydrogeologically, Volo Bog is actually a poor fen rather than a true bog as it does receive some ground water and run-off. Strictly speaking, a true bog gets sky water only - rain, snow, etc... Many peatlands we we call bogs don't qualify by this hydrogeologic definition. Such bogs are exceedingly rare, perched on mountain tops and atop jills such as those on the headlands reaching out into the ocean. Blanket bogs creep uphill, the absorptive sphagnum moss wicking the water against gravity! Kettlehole bogs can begin as poor fens then become more bog like as the peat accumulates above the high waterline.

What is peat and how does it form?


Peat is organic soil made up of poorly decomposed plants - especially sphagnum moss. Lack of oxygen in the stagnant bog water, plus acids released from the plants, inhibit bacteria. Without bacteria, dead things don't decompose. The soil in a bog is stingy - it doesn't give up its nutrients easily. More on this later.


Northern European bogs have long been mined for peat which is burned to heat homes and generate electricity (this is even dirtier than coal). Over 1,000 dead human bodies have been discovered in these European bogs, most around 2,000 years old! Check this out! 


Peat in a bag or peat in a bog? Or, "Why do we put peat in our garden if it is nutrient poor?" It is not! The nutrients are just trapped. When released from a bog and exposed to oxygen and bacteria, the nutrients quickly become available. The peat we buy at our favorite garden center very likely comes from a peatland which will never be the same after its soil is removed. Composting and using other alternatives to peat for our gardens helps to protect bogs. Learn more at


Do Tell more about sphagnum!


Sphagnum moss is the building blocks of bogs. The various species of sphagnum are super absorbent and acid producing. Sphagnum carpets bogs, holding in moisture and even wicking it up above the water table. Its acidity made it useful as a sterile field dressing for battle wounds in early battles such as WWI and earlier. Its absorbency was appreciated by Native American moms who lined their baby's cradle boards with it as an early disposable (and biodegradable) diaper!



What other plants are found in bogs?


Bogs are much about plants! Because dead things decompose slowly in bogs, their nutrients are trapped and not released into the bog soil. Therefore, bog plants have some strange adaptations to help them survive in this nutrient poor environment.


  • Northern Pitcher Plants are carnivorous plants whose leaves have evolved into cups or pitchers that hold rainwater. These act as death traps, luring victims with a promise of sweet nevtar. Down pointing hairs make for a slippery ride down to the pool of water below. The victim tries to climb out past spiky hairs and a layer of slime, but to no avail. After a struggle, the victim drowns. Not every critter is trapped by the water. Here lives a whole ecosystem of critters adapted to living in the pitcher. These little animals devour the unlucky ones. Their digestive leftovers (poop high in nitrogen & phosphorous) are absorbed directly by the leaf.

  • Round-leaved Sundew used to be found in Volo Bog. This carnivorous plant traps victims in sticky tentacles. The sundews were collected by early botany students in the 1950s and 1960s. It is now illegal to collect from Volo Bog.

  • The Health Family includes Leatherleaf, Blueberry, and Cranberry (each found in Volo Bog) plus others not found in Volo Bog - Bog Rosemary, Bog Laurel, Sheep Laurel, Labrador Tea, and others. This family features a cadre of root friends call mycorrhiza. Mycorrhizae are fungi who job is to capture nutrients from the soil and make it available to the plants' roots. It is a mutualistic relationship with the plant providing carbohydrates to the mycorrhiza.

  • Poison Sumac, a member of the cashew family will give an itchy rash to those who come in contact with its sap which can leak out of any part of the plant. It grows as a tall shrub up to 20 feet high. Watch out for its compound leaves with red stems growing from gray branches.

  • Orchids love bogs. Dozen of orchids grow in bogs around the world. Rose pogonia can still be found growing each June into July in Volo Bog. Other bog orchids include grass pink, lady's slippers, bog twayblade and others.

  • Ferns also thrive in bogs. Volo Bog features six species: cinnamon fern, sensitive fern, royal fern, marsh fern, spinulous fern and crested fern.

Where are bogs found?


Bogs develop in low lying areas such as glacially formed kettle lakes and poorly drained lowlands, as well as on mountain tops in moist environments. Blanket bogs actually creep up hill with sphagnum pulling the water along like a living, growing sponse.


Bogs are a north-country habitat. Volo Bog is near the southern range of glacially formed bogs and has the distinction of being one of the southernmost open-water quaking bogs in North America. It was designated an Illinois Nature Preserve (the 25th in the state) in 1970. In 1973, it was designated a National Natural Landmark by the U.S. Department of the Interior, National Park Service!


Learn More! Look for the links to "Explore other Bogs!"

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