The part of our garden that we call the bog isn't a bog in the traditional sense of the word - it's not an area with permanently moist, acidic peaty soil. Ours is an integral part of our big pond: water is continuously pumped from a skimmer alongside the main pond area up into the center of a rubber-lined volume of rocks and pebbles. There is a shallow water level above the top layer of pebbles, from which water flows back across a ford into the main pond. I'm not quite sure why the pond installer chose to refer to this feature as a bog, but the term has stuck. The bog serves as a biological filter: leaves, algae, and other organic
matter that arrives from the main pond gets hung up in the pebbly medium.
Here, bacteria are hard at work, converting them into nutrients. Completing
the job, the plants
growing in the bog remove these nutrients from the water and use them to
grow. By doing this, they keep the nutrient level in the pond low, which
prevents algae from taking over. The gentle trickle across the ford aerates
the water, which also improves water quality. So far, in their first full
year of growth, the bog plants haven't reached their full photosynthesizing
potential yet. But already, the difference between the water quality in our
big pond and our original puddle pond is striking -
near crystal clarity in the big pond, a mucky green soup in the little one.
The bog is a substantial feature all in itself - about ten foot long and eight foot wide. Because of the way our yard slopes, the bog sits above ground level, its walls constructed from soil excavated from the main pond. This means that not only did we get a new opportunity to grow plants in the bog, we also have a substantial new area of sloping soil around the bog to serve as brand-new plant borders. A maple tree that was left in place during pond construction is near one of the back corners, and provides some welcome dappled shade to the area. One edge runs along a narrow strip of lawn between the bog and our established side garden - a very pleasant place to stroll, making this a prime area for well-behaved plants. So far, we've placed a slow-growing Japanese maple and a Meyer lilac (both still tiny) in this area, along with small perennials and annuals to fill in during the first season, and several clumps of blue fescue grass along the length of the border.
The bog itself was originally planted by the company that installed the pond. Unfortunately, the bog sprang a leak in its first winter, so that the poor plants were exposed to dry freezing conditions - quite a few of them didn't survive. We've added new plants to fill in the gaps. Low plants grow in the front area nearest the ford, taller ones in the back. Just so it lives up to its name a little bit, I planted a couple of pitcher plants (true bog denizens!) along the edge as well. In years to come, I expect that the bog will be an impenetrable mass of green by mid-summer, greatly adding to the filtration capacity of the pond. We'll keep you informed with annual updates! Plants growing in our bog filter
Plants growing alongside our bog filterVisitors to this page have left the following comments
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Last modified:
February 02, 2008 |
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The other edge available for planting runs along the back of the bog,
just short of the chain-link fence dividing our neighbors' and our yards.
We're happy to hide that fence from view, so the back of the bog is planted
with taller plants - shrubs, ornamental grasses, taller perennials. The tall
arborvitae lining the neighbors' yard cast shade on this area for the first
half of the day, so we've also tucked in some plants that appreciate partly
shady conditions. At this time, we can still walk on the narrow path between
the bog and the fence, but as plants grow larger, this will cease to be
navigable.