If you've ever seen a bog with its one-of-a-kind mix of carnivorous plants, orchids and other unusual species, you might have found yourself thinking: I wish I could create one of those in my garden.
Actually, you can. And you don't have to live on the edge of a pond or swamp to do it!
As long as you have an area that gets at least five hours of direct sun a day, you can create your own bog garden. Better yet, you can even create one in a pot. From the size and shape of a container to the size and shape of an in-ground bog you dig out yourself to the plants you choose, your only limitation will be your imagination.
The first step to creating a haven for carnivorous and other unusual plant species that will stop visitors — as well as pesky insects! — in their tracks is to gain a basic understanding of how bogs form in nature. That knowledge will give you more than one "Aha!" moment as you discover the principles of establishing and maintaining a garden bog. After all, growing a self-sustaining plant like a pitcher plant that feeds itself by attracting and devouring insects is far different from growing even the fussiest plant in your garden.
What is a bog garden?
While there are different kinds of bogs, a bog is essentially a type of freshwater wetland that formed from decaying plant matter during the course of hundreds, or even thousands, of years. Over time, the decomposing plants created thick layers of soft and spongy peat, which to almost everyone but a scientist give bogs the appearance of a muck or a quagmire.
Because of their layers of waterlogged and decaying plants, bogs are low in oxygen and nutrients, acidic in nature and infertile. They receive water only from rain, which means that bogs and the plants that grow in them don't receive nutrients from runoff from adjoining land. The result is a great biodiversity of plant communities that thrive in these unique growing conditions. The communities include sundews, carnivorous plants such as pitcher plants and venus fly traps, tiny ferns, mosses, liverworts and orchids. The plants in these wetland communities are often unusual not only in their appearance, but in how their needs have adapted over the eons. They thrive with "wet feet" while growing in full sun without any need for typical soil nutrients and, in some cases, on very small levels of nitrogen. The carnivorous plants trap their food in a variety of specialized botanical structures. Many other bog species, such as the orchids and some of the blueberries, have specialized relationships with mycorrhizal fungi that colonize the roots and harness nutrients from the sodden mass of the bog.
Fortunately, it won't take you centuries to create a bog garden. Paul Blackmore, manager of the Fuqua Conservatory at the Atlanta Botanical Garden who has looked after the garden's in-ground and potted bogs for the last eight years, offered some tips on how homeowners with basic gardening skills can create their own backyard bog. "It is easy to create a healthy, functioning bog," he said, "as long as you stick to some basic principles." Here are Blackmore's principles and the the steps he suggests for putting them into practice.
How to make a pot bog garden
- Choose a container that is a minimum of 8 inches deep. Almost any pot or container that will hold water will work.
- Create a planting media by mixing 1 part builders' sand (available at box and hardware stores) with 4 to 5 parts peat moss (available in garden centers).
- Line the bottom of the container with 2 to 3 inches of sand.
- Fill the remainder of the container with the planting media. The planting media should be a minimum of 6 to 8 inches deep.
- Hydrate well with clean water and then leave it alone for a couple of days before planting so the peat has time to fully absorb the water you've added.
- Carefully plant your plants and then interplant among them with live moss. The moss with help maintain a stable hydrology and biotic environment. It will also help prevent dry out. The moss can be collected from wet woods (be sure the woods are not on public park land and ask for permission if they are on private land), or you can purchase it commercially.
- Place the pot in a sunny, open area. You should ensure that the media never dries out and you should only use clean tap water.
- It is essential to avoid all fertilizer. Nitrogen and phosphorous are toxic to pitcher plants. Remember, they get their nutrients from insects they trap.
How to make a ground bog garden
All the same principles apply, except in this case you may make the bog deeper. You just don't want to go any deeper than 10 to16 inches.
- Two to three days before digging out the pit, begin hydrating the peat moss you will use for your planting mix.
- Choose a level and open sunny spot.
- Dig out a natural-shaped pit with vertical or slopping sides.
- Ensure that no sharp objects, roots, stones, etc. remain.
- Put 1 to 2 inches of sand in the bottom of the pit, and then lay a liner over the sand and across the pit, ensuring that you have enough liner to lap over the the sides of the pit. A word of caution about liners: Use a quality pond liner if you can afford one. If not, a shower curtain will work. Tarps tend to degrade very quickly, so avoid those. Edge the pit with stones to give the bog a natural look and to hold the tarp in place.
- Put 2 to 3 inches of sand at the bottom of the pit over the liner.
- Using a shovel, mix the hydrated peat and sand (as above) on a clean, flat surface.
- Carefully place the media into the pit, covering the sand, and gently firm it with the back of a rake.
- Plant once the media is fully hydrated but not waterlogged. It is important to dig down into your bog to ensure the peat is thoroughly hydrated. You can plant as soon as the media is moist at every level.
- Be sure to interplant living moss among your plants.
Keeping your bog happy
There are three main things to remember to make your bog a happy bog:
- Ensure the bog is always moist if not wet.
- Use only clean water with no fertilizer.
- Keep a keen eye out for weedy species and grasses. Nature doesn't like bare earth of any kind and will do all it can to turn your bog into a meadow and then a woodland. Keep a vigilant eye to exclude or control unwanted species.
Top plants for a bog garden
The blazing star (Liatris spicata) won't eat any insects, but it will had a burst of color to your bog garden. (Photo: Rachel Kramer/flickr)
Many species of plants can be used in a bog garden: pitcher plants. orchids, sundews, liliums, hymenocallus, bog daisies… the list goes on and the choices are almost endless, said Blackmore. Sometimes, he advised, it comes down to what you can find in the market. Here, though, are his top plant choices for home bog gardens.
Pitcher plants: Sarracenia leucophylla, Sarracenia flava and Sarracenia purpurea
Orchids: Calypogon tuberosus and Pogonia ophioglossoides
Ferns: Osmunda regalis
Sundews: Drosera (many species)
Bog daisy: Helianthus angustifolius (may become invasive)
Blazing star: Liatris spicata
Venus fly trap: Dionaea muscipula
Sources for bog plants
While some of the general-interest garden centers do carry pitcher plants and a few other species suitable for bog gardens, Blackmore said home gardeners will find the best and most affordable plant choices online. He also said to look for bog plants at specialist nurseries in your area. Better still, he added, you should visit a natural bog such as Splinter Hill Bog near Perdido, Alabama, or the wetlands at the Highlands Biological Station in Highlands, North Carolina.
For further reading...
Blackmore recommended a book called "The Savage Garden" to learn more about creating a bog garden. He said it's a fantastic bog garden starter guide and a great gift for any child interested in nature.