Natural ponds and other watery places, when left to their own devices, tend to be associated with surrounding boggy bits. These can provide a wonderful growing area for all kinds of special plants such as marginal plants or bog/wetland plants. Both native an cultivated plants enjoy this environment. Such as ragged robin (lychnis flos cuculi), water avens (geum rival) and Louisiana irises (see below). Such varieties thrive in ground that is consistently boggy and wet, growing in areas that seldom dry out. What they don’t need is soil that is constantly under water.
Location, location, location
In reality, when we make a pond, we can’t assume that the surrounding area will provide such a specialised environment. In most gardens, the opposite will be true. Soil in around the pond – right up to the liner – will often be more on the dry side.
Most pond plants are absolute sun-worshippers, the best place to build a pond is in the sunniest spot in the garden. Great for the water lilies and marginals, but the surrounding ground will probably be as dry as a chip. So, when planning your new pond and planting scheme, you may want to think about constructing a wetland area.
Excavate the area around the overflow from your pond to a depth of about 25-45cms. Line with a piece of pond liner. If you incorporate the area into the design of your pond, using the liner from the main pond, so much the better. Perforate the bottom at the deepest point with holes using an old screw driver. Fill the dip with ordinary heavy garden loam or Westland Aquatic Compost. Above all, make sure the area is constantly wet through.
You will need to keep a watchful eye on the wetland, or it will become full of weeds. So don’t make it too large or parts will be inaccessible.
A happy medium
By using a range of planting baskets it is possible to achieve a similar environment in the pond itself. If you don’t want to make a dedicated wetland garden, you can still grow these wonderful plants. You just need to create mini boggy bits using shelves in your pond.
We would always recommend that you include several shelves at different depths when installing your pond. These must be deep enough and wide enough to accommodate planting baskets. We suggest 15-30cms wide with a depth of water covering the shelf of between 10 and 20cms. This will provide space for baskets from1/2lt up to 10lt.
You can then plant bog plants into a planting basket and place so that the soil is just above the water surface. This will replicate the same growing conditions as in a bog or wetland area.
Remember that while many plants listed as marginal plants can also be grown as bog plants, this is not true the other way around. Bog plants will not survive under water, so be careful to get the soil at just the right level.