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Bog Gardening
by Theresa Schrum

The concept of bog gardening arose several years ago as a spin-off of the popular trend of water gardening and ponds. Many gardeners who had installed ponds often included a bog as part of their overall plan. Then the idea of creating a bog as a separate entity, sometimes without a nearby pond, took off.

Bog gardens are created to mimic those bogs found in nature. Natural bogs have low or runoff areas that go from being flooded with standing water to moist. Bogs can be found in nearly all parts of the world from the arctic regions to the tropics. The plants found in these highly specialized ecosystems range from the beautiful to the bizarre. In the Southeastern United States, natural bogs are home to such plants as the carnivorous pitcher plants and Venus flytraps.

 

Building Your Bog


 

If you plan to have a pitcher plant bog, you need to carefully consider the site. Pitcher plant bogs need full sun (at least six hours of direct sun each day). Such bogs would also need to be protected from garden chemicals such as fertilizers, herbicides, fungicides and insecticides. Therefore, the site should have a slight slope away from areas requiring high chemical maintenance to prevent runoff during rain or irrigation.

Construction of a bog is somewhat similar to a pond; the difference is that the bog must have a gentle slope to allow water to flow across and out of the bog and it should be 18 to 24 inches deep. You will need a flexible or preformed plastic pond liner and rocks, cinder blocks or logs to hold the liner in place.

Dig the hole and remove any sharp debris from the bottom. One end of the hole needs to be slightly higher than the other. Install the flexible liner and remove any wrinkles or drop in the preformed liner and backfill to hold it in place. The flexible liner should be large enough to extend at least 12 inches beyond the dimensions of the hole, but wait until the bog is filled and the liner is secure before cutting it. The preformed liners should be at least 6 inches above the soil line. On the uphill side of the bog, create the berm using the soil excavated from the hole. The purpose of this is to prevent topsoil, clay and chemical contaminants from entering the bog.

 

Soil Requirements

The soil requirements for pitcher plant bogs are somewhat specific yet easily obtained and made. You will need coarse river sand (not play sand) and milled sphagnum moss. (See list at bottom of page for an example of amounts needed.)


Louisiana iris is a bold and beautiful specimen that thrives in a bog garden.


Pitcher plants are considered some of the most interesting plants for a bog because they are carnivorous.


Ferns, such as this cinnamon fern, blend perfectly with a bog setting.


Spider flower is an eye-catching element in this bog garden.


With its evergreen foliage, sweet flag can be planted among the rocks securing the bog liner, or along the edge of the bog to soften the appearance and lend a more natural look. The light green foliage of variegated varieties complements the dark purple foliage of the pitcher plants.


Bogs can be planted in preformed pond liners and included in an overall water feature design. This bog has already been planted and will be installed alongside this pond.

Fill the bottom of the bog with 12 inches of the coarse river sand. Smooth the area and moisten the sand to help pack it down. Do not wet the sand to the point of standing water. The water should flow and accumulate at the lowest point of the bog. This is the area where water will run out of the bog and continue downhill. Smooth the sand once more and allow it to stand.

Place the sphagnum peat moss in a separate wheelbarrow or on a large tarp. Chop and moisten the peat moss until it is easy to work with and not blowing away. Thoroughly mix the peat moss with the river sand in a ratio of 3:1 (peat moss to sand). This does not have to be exact, and ratios of 2:1 will also work.

Fill the bog the rest of the way with the peat/sand mixture and water the bog slowly from the top until water flows out through the low end. Add additional peat/sand mix as settling occurs. At this point, you will want to let the bog stand for several hours or a day.

After the bog has stood for nearly a day, get a group of friends together (kids really enjoy this part) and stomp through the bog to compress the soil. Water should bubble up with every step. Add additional peat/sand and water as needed. Once compacted, smooth the top layer and if using a flexible pond liner, secure it in place with rocks, blocks, or whatever. Cut away the excess liner, leaving at least 12 inches beyond the dimensions of the bog.

 

Planting the Bog

Once the construction is complete, you are ready to add your plants. Many plants will grow in wet soil, but sphagnum bogs are unique. The soil is very acid and low in nutrients, and only plants naturally adapted to these conditions should be used. A sphagnum bog should never be fertilized.

When all of the plants have been installed, water the bog garden again for at least 30 minutes. This is often made easier by the installation of a soaker hose tucked discretely against the edging on the uphill side of the bog. Water the bog daily on dry days for 30 minutes. Continue this process for the entire first growing season. Once established, it will probably only need to be watered two to three times each week during periods of drought. If possible, use rainwater or municipal water that has been allowed to stand for at least a day. Rain barrels filled with water and connected to the soaker hose will often work well. Many bog plants are sensitive to the chemicals contained in municipal water.

It is also recommended that you place plants on the berm above the bog to help hold the soil in place. I have found that plants such as rush (Juncus effusus) or sweet flag (Acorus spp.) do well in this location and on the edge of the bog. Pitcher plants (Sarracenia spp.) and Venus flytraps (Dionaea muscipula) are among the most interesting plants for the bog. Children and adults are often drawn to these plants because they are carnivorous. In some states such as Georgia, all pitcher plants are protected, and all reputable sellers are certified by the Department of Natural Resources. This is an attempt to stop unscrupulous people from collecting plants from the wild. Only purchase pitcher plants from legitimate growers who can prove that their plants were “nursery propagated.” Never “feed” your carnivorous plants insects, hamburger or anything else. They have adapted ways to obtain prey on their own.

 

Interesting Note

At the beginning of fall, the “tubes” of pitcher plants can be removed and cut open to examine the contents. It’s often interesting to see the “diet” of your pitcher plant.

 

Bog Container Gardens

It is possible to grow a bog garden in a container. Use a container that does not have a drain hole or line the container with a flexible pond liner. Use the same ratios of sand and sphagnum peat moss for your container garden. Water it daily as containers can dry out faster.

 

Materials Needed
(based on a 10-by-10-foot bog, 18 inches deep)

• River sand for base and soil mix: 4.2 cubic yards

• Sphagnum moss cubes: 9 (2.2 cubic-foot cube)

• Flexible pond liner 15 by 15 feet or rigid plastic pond of the correct dimensions

• Rocks or cinder blocks to cover 40 feet in length

• Soaker hose

 

Sphagnum Bog Plants

• Pitcher plants (Sarracenia spp.)

• Venus flytraps (Dionaea muscipula)

• Rush (Juncus effusus)

• Yellow-eyed grass (Xyris spp.)

• Bog sedge (Carex spp.)

• Hatpins (Eriocaulon compressum)

• Ladies’ tresses (Spiranthes cernua odorata)

• Rain lilies (Zephyranthes atamasco)

• Sweet flag (Acorus spp.)

 

 

(Photos by Theresa Schrum & Peter Gallagher)

Posted October 2011

 


Theresa Schrum is a Certified Arborist and the owner of Eco-Terra Landscape Consultants.

 

       

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