By Howard Voland
Photos by Howard Voland
There’s something about plants that eat animals that fascinates us. Fortunately, human-eating plants like Audrey 2 in Little Shop of Horrors only exist in science fiction, but carnivorous plants do grow in the Pacific Northwest.
The tiny common butterwort, whose sticky leaves ensnare and digest gnats, can be found growing on the wet rock walls next to Lower
Bridal Veil Falls, just a few feet off the Lake Serene Trail on the slopes of Mt. Index. It blooms in late spring and has a lovely, jewel-like flower.
Sundews can be found in boggy areas throughout the region; while the impressive Cobra Lily, Darlingtonia californica, has an Oregon state park devoted to it just a few miles north of Florence.
While most of us do not have a true boggy area in our yards suitable for such plants, creating one has never been easier. And there is a certain diabolical enjoyment in watching a fly or mosquito disappear down a pitcher plant’s lovely throat.
These plants are unusual, beautiful and interesting, with long lasting flowers of uncommon interest, and kids find them fascinating, too. Some nurseries even have small bog gardens in planters ready to take home.
The defining characteristic of a bog garden is that it contains soil that is always moist but has a water level several inches below the top of the soil. In other words, a bog plant should not dry out but its base should not be under water.
A bog garden can be created in a variety of ways. Instructions and suggestions for building your own bog garden can found online by simply doing a search for “bog garden.” Most nurseries selling bog plants will also be happy to give you detailed instructions.
But like most of you, we have limited time so we kept it simple. Our first bog garden was a $20 plastic planter about 28 inches long, a foot wide and ten inches deep with no drain holes.
We first drilled a row of small drainage holes about three inches below the top on both sides of the planter. These drainage holes establish the bog garden’s water level.
In the middle of the planter we placed an empty plastic nursery pot that had plenty of drainage through the bottom. This is the inner water pot, which is the bog garden’s water reservoir, which is also used for maintaining the water level. The general recommendation is that open water should make up about 25 percent of the bog garden.
The rest of the planter was then filled with a 50-50 mixture of builder’s sand and commercial peat moss, which had been moistened.
Be careful not to use beach sand or anything contaminated with salt, additives or weed seeds. That goes for any liners, artwork or anything used that has contact with the bog garden’s soil and water.
Do not add any fertilizer. Carnivorous plants get their nutrients from the insects they digest. Bog plants want an acid soil with a pH
between 4.0 and 6.5. Generally the peat moss will ensure that level unless there is some type of alkaline contamination.
Next we added water to our bog garden until it drained out the side drainage holes and until the inner water pot maintained that same water level. We also tested to see how fast the bog garden container would drain in the case of a heavy rainstorm. It is important that the crowns of bog plants not be underwater for any length of time.
To take care of any mosquito larvae in the inner water pot, we added mosquito dunks in accordance with the directions. As long as the surface soil remains moist, the water level in the inner water pot can drop to a couple of inches before it needs to be refilled.
Finally we added pitcher planters, sundews and cobra lilies and placed our new bog garden planter on a sunny part of our deck. In our area, bog gardens can usually take full sun but in hotter areas, they need some midday protection.
That winter, we moved the bog garden container to a sunny place in the garden and dug it in deep enough to protect the plants’ root systems but also made sure that the side drainage holes were exposed to maintain proper drainage.
Within two years, our carnivorous plants needed dividing so we bought a considerably larger hard plastic commercial pond liner and essentially followed the same procedure as above with one exception. We dug the liner halfway into the ground and then created a fast-draining rock garden around the upper half.
We’ve had only a couple of annoying problems. The first was when the planter was on the deck. Blue jays were able to find a nearby perch and peck holes into the pitcher plants to get at the flies inside. We simply moved the planter further away from their perch.
The second was an undisciplined neighborhood dog, who decided the inner water pot was great for drinking water. We upturned a nursery pot inside the water pot and put a large rock on top of it so the dog couldn’t reach the water.
But the dog still tried. So we booby trapped the surface of the bog garden with thorny rose stems and sprayed the plants with deer repellent. That finally worked.
Bog garden plants can be ordered online or purchased at some specialty nurseries. Locally, Oudean’s Willow Creek Nursery in Snohomish specializes in carnivorous bog garden plants. Or if you have a friend with a bog garden, see if they are ready to do some dividing.
Our bog garden is limited to just carnivorous plants because it is still relatively small, but there are also many non-carnivorous plants suitable for bog gardens. In larger bog gardens the inner water pots can also be used for some types of water plants. Bog gardens can also be part of a larger water feature.
To see a larger bog garden that includes both carnivorous and non-carnivorous bog plants, which was dug into the ground and lined with plastic pond liner, visit the Master Gardener Display Garden at McCollum Park between Mill Creek and Silver Lake at 600 128th St. S.E., Everett.
It is across the parking area on the west side of the WSU-Snohomish County Extension Administration Building, which is also home to the Master Gardener permanent plant-problem clinic, open 9 a.m. to 4 p.m. weekdays through September, and 11 a.m. to 3 p.m. October through April. For more information, call (425) 357-6010.
Howard Voland draws upon sixty years of playing in Snohomish County dirt, and, the opinions expressed here are his alone. You can reach him through www.ravenwriters.com.