Outdoor Bog

MAKING AN OUTDOOR BOG FOR CARNIVOROUS PLANTS

Many carnivorous plants will survive winter outside in the St. Louis area if provided the proper accommodations. A bog can be created for your carnivores using a pond liner filled with peat moss and sand instead of water. Because it has little or no drainage it retains the moisture needed for most carnivorous plants. Combined with a little pond installed next to it, a carnivorous plant bog can be a beautiful addition to your landscaping.

Materials needed:

A prefabricated pool, a pond liner, or a kiddie wading pool

White silica sand (A fine white sand used in sandblasting. It can be found in 75 1b bags at some     hardware or lumber stores.)

Peat moss (NOT peat humus). Make sure there are no fertilizers added.

Dried long-fibered sphagnum moss (optional)

Rain water or reverse osmosis filtered water (see below under watering section) 3/4" PVC pipe and         cap, plastic tubing (optional)

Location: Choose a location that is mostly to fully sunny. Some protection from western wind is appreciated. The area should not be prone to flooding or run-off.

Bog Construction: Dig a hole to accommodate your pre-formed pool or liner. The depth of your bog should be at least 12" deep, but 18" — 24" is even better. Be sure the pool is level in its hole. A few small drainage holes toward the top of one side is often recommended to drain excess rain water: put the holes about l" to 3" from the top of the liner. This is an optional step: some people don't use it at all. Make sure the sides of the liner or pool extend a bit higher than the surrounding garden soil or pond, you do not want water to run off the garden into the bog, since that would bring in unwanted nutrients and salts. You may want to install a PVC pipe vertically in the center of the deepest part of the bog. This allows you to put a stick down it to measure the depth of water in the bottom of the bog at any time. Place a cap over the pipe opening and cover it with planting media and/or moss to hide it.

Planting Media: Put 3 - 4" of white silica sand in the bottom, as a filter layer. Fill the rest of the bog with a mix of 1/2 peat moss and 1/2 silica sand. Moisten the peat moss first with rainwater or distilled water and break it up. Mix the sand (preferably pre-washed) thoroughly with the peat moss. Adding some well moistened long-fibered sphagnum moss to the mix helps to prevent compaction and improves air flow to the roots of the plants. Fill the bog to overflowing: it will settle quite a lot. Create a mounded area for plants that like it less soggy, such as Venus flytraps, especially if you don't use drainage holes. You can create such a raised area by placing some logs to create "walls" and adding more sand/peat mix to fill up the logged-in area. Cedar logs work especially well. You may also want to create a lower, wetter section of the bog, for the species that like it particularly wet.

Watering: Water your bog well before planting and give it time to settle, adding more media as necessary. Use only distilled water or rainwater, tap water and well water in the St. Louis area is too high in minerals and salts, and will eventually kill any carnivorous plants. Reverse osmosis filter units can be purchased, or you can collect rainwater by placing a container under your roof's drain spout. Be sure to use only relatively clean rain water: when only a little rain falls, the first water off the roof can be quite dirty. Discard, and wait for heavier rain. Transfer clean rainwater collected to large plastic trash cans with tight fitting lids to keep out mosquitoes.

Moss: Live sphagnum moss can be used as a soil covering, but it can become overly aggressive: keep it away from smaller sundews and seedlings that it can quickly overwhelm. It benefits from a little shade, as your plants grow they will help to shade it, and likes to be watered from above. Keep it quite moist; it will need daily watering during its first summer. Once it becomes well established, it is easier to maintain. Do not use mosses from your garden, as they require different soil conditions and may actually help to change the conditions in your bog.


Adding a Pond: Aquatic carnivorous plants can be added to your bog by placing a liner within your bog for a water feature, or by adding a small pond next to the bog. It can be as small as a foot in diameter to support Utricularia gibba, or larger for other plants. Use only rainwater or distilled water to fill it. Add a layer of peat moss on the bottom to acidify the water (Peat will float for the first few days; then the majority will sink, and the rest can be skimmed off.

Plants to Try in Your Bog


Pitcher Plants: Sarracenia species of almost any type will generally be hardy in St. Louis. Parrot pitcher plants (Sarracenia psittacina) are probably the least winter hardy, and they require the most water, sink their pots in a water pond during the summer and remove them to a protected location in winter.

Sundews: Drosera rotundifolia, D. filiformis, D. intermedia and any other temperate sundews should work in your bog. Rosetted sundews benefit from a little shade; they like to lie close to taller plants such as tall pitcher plants. Taller sundews, like D. filiformis need full sun.

Venus Flytraps: Dionaea muscipula are reasonably winter hardy but they must be kept excessively soggy in winter. They like lots of sun but will tolerate a little shade. They should be placed a bit higher and drier than other carnivorous plants, but should never be allowed to go completely dry. They benefit from being divided and replanted with some fresh media every year or two.

Bladderworts: Utricularia species are the only carnivorous plants native to Missouri. Utricularia subulata is terrestrial, and is therefore planted in the soil mixture within the bog, preferably in the wettest corner.  U. gibba is a good floating aquatic for a small water feature. U. macrorohiza is an aquatic species suitable only for larger water features.

Butterworts: Try hardy Pinguicula species that form winter buds. Most of these come from the northern U.S., Canada, or Europe, and may not like our humid, hot summers. Southern U.S. varieties may not be winter hardy here.

Protect Your Bog Over Winter: After several hard freezes have put your plants completely into dormancy (early December), cover the bog with evergreen bows or pine needles. Do not use leaves or straw, as these can easily mat down and rot, causing fungal problems. Burlap or old sheets can be placed over top if desired; don't use plastic. Remove protection promptly in spring to prevent rotting in warm weather.

Obtaining plants: Some plants are available at local garden centers, but most will need to be mail ordered. Be sure any plants you obtain are nursery propagated, NOT collected from the wild. Most plants today are propagated from tissue culture, so the Venus flytraps you see in stores are generally from tissue culture, not taken from the wild. To be certain that you are not contributing to the demise of wild plants, always ask suppliers how their plants were obtained!



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