| - By Vijayalatha, K.R., K. Padmadevi and M.Kannan Horticultural College and Research Institute, Coimbatore |
A bog garden is an area or pocket of saturated soil that is never allowed to dry out. A bog is a unique feature almost a combination of a land and water garden. This garden is an inexpensive and beautiful way to expand your water garden or koi pond. It is essential that the soil of the marsh garden should be kept in a moist, swampy state throughout the year but it should not be flooded. Bog gardens can exist independently of the pond or can also be an integral part of it. A bog garden contains fascinating flora including carnivourous plants, orchids and other acid loving species.
Types of bogs
A. Wild bog
Bogs or wetlands are low lying areas in the natural terrain where flora and fauna thrive in a moist environment
Natural bogs often form in glacial lakebeds and shallow depressions over hundreds of years
May be of the shallow sub-surface rock layer, which holds in the water
Habitat where slow movement of water creates conditions for slow decomposition of dead plant matter
Soil may be high in organic matter and quite acidic: sphagnum/ peat moss may be present
In some habitats, carnivorous/insect catcher plants such as Sundews, Pitcher plants, or Venus' Flytraps may be found |
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B. Ornamental bog gardens
Created within the perimeter of the water garden by using a permeable retaining wall to confine the soil and separate it from the open water of the pond
Extension of pond liner and creation of barrier lets water permeate the soil but prevents soil from falling into the pond Iindependent bog; oasis garden; damp garden; irrigated bog garden:
Created by underlying the bog garden with a non-permeable membrane that slows down the movement of water through the soil
Made with liner independent from pond allowing greater flexibility in silting and shape
As liner is completely covered with soil and not exposed to deterioration from ultraviolet light, cheaper materials like polyethylene can be used
No water level to be maintained as in a water garden, so construction need not be watertight; perforation of liner fabric recommended to prevent stagnation and anaerobic soil
Constructing Bog Garden
Site Selection A low spot that naturally collects water may be the perfect site for a bog garden. Even clay with slow drainage may be a bog garden site. Most plants for bog gardens are sun lovers. Therefore, the bog garden site should receive at least six hours or more of daily sunlight. The main viewing area (path) should be from the south side. You can use rope or garden hose to mark an outline, which will be the perimeter of the bog. Leave a 6-8 foot space on the north side of this bog if you plan on using large background plants. The bog garden does not have to be connected to your water garden. The advantage is its easiness in maintaining the moisture level. When the soil seems dry, water it. In dry climates, consider an irrigation system using a soaker hose or perforated pipe along the bottom of the bog.
Preparing the Bog
Dig the outlined bog to a depth of 12-14 inches, removing soil to form a basin. The bottom should be mostly flat, level or slightly pitched. The sides should go mostly straight down.
If moles or tunneling rodents are a problem in your area, line the basin with galvanized hardware cloth, screening, or heavy, woven weed cloth/barrier. Use rot/rust resistant materials.
Line the bottom and sides of the basin with 4-6 mil plastic sheeting (on top of any mole/ rodent protection.) Leave plenty of excess plastic along the edges; it can be trimmed away after the bog is filled and settled. Cut several 10-inch slits in the liner base, every foot or so. This will allow the bog to drain, while the liner holds most of the moisture in the bog.
Made with liner independent from pond allowing so. This will allow the bog to drain, while the liner holds most of the moisture in the bog.
Add 2-3 inches of moist sand to the bottom. Coarse sands are good to use. Do not use beach sand
Fill the remaining basin with 1 part sand + 3 parts peat moss, dampened and mixed well. Tamp the mix in place using a bow rake; this will reduce settling of the mix. The bog should be filled until it is about an inch below surrounding existing soil level.
The lining materials can be trimmed as needed. It is wise to leave about 12 inches of liner/mammal guard exposed in case the bog settles further; this edge can be hidden with mulch, pine needles, rocks, etc.
If you have a pool or pond, place the bog garden next to it, so that the bog blends harmoniously into the landscape. If you connect the bog and the pool with a length of pipe to allow the water to flow freely, the pond can provide water for the bog. This will also keep water levels in both enclosures constant. If you don't have room for an in-ground bog, you can still have a bog garden. Try using an old barrel or other container that holds water like even wading pools, utility sinks and even old bathtubs can be used to make bog gardens. To add a bog garden to your existing pond you can use any container that holds water. Fill the container ½ with soil that does not contain floating additives like perlite or vermiculite. Plant any moisture loving plants into the soil and keep it filled with water. A few small goldfish or minnows will keep the mosquito population down. A bigger bog garden can be built by digging a shallow pond or raised bed 6" to 12" deep and lining it with a waterproof material or pond liner (an old split-open waterbed mattress works well).
Fill it ½ with soil and fill with water. Most of the bog plants like acidic growing conditions, which can be achieved by adding peat moss (up to 50%) to the soil. The peat moss should be well saturated with water before mixing to prevent it from floating. Adding fertilizer to bog plants will tend to cause algae growth. A bog garden is one of many kinds of rain gardens. They are shallow ponds, often with natural bottoms that are located in a low part of the garden. You can trap water from the down spout and gutters of your house. Build an aqueduct to the shallow or low spot and you have a bog garden or rain garden. You can move your bog garden farther from your down spouts by digging a 6" to 12" trench about 4" deep and filling it up with small pebbles. The water from the down spouts will then travel down your drain to your bog garden. |
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