As discussed earlier in Bog Garden Styles, whilst the area alongside a natural stream or pool is ideal for moisture-loving plants, you can also add a bog garden next to a man-made pond by creating special beds. This can make it easier to keep moisture-lovers such as primulas and astilbes looking their best, without having to water each one by hand.

The following guide will show you how to build and plant up a bog garden next to an artificial pond. When building such a bog garden, it is important to remember that although it may appear to be connected to the pond, it is in fact separate; the pond water is kept away from the soil and vice versa.

1. Dig the Hole

Mark out where you want your planting beds to be situated, and then dig out a saucer-shape hole at least 45 cm (18 in) deep. Keep the top soil separate from any subsoil. You will need to remove the roots of any perennial weeds such as couch grass.

2. Line the Planting Area

Line the hole with a thick-gauge polythene to retain moisture, and hold it in place with some stones or bricks. Using a garden fork, puncture it with a number of holes so that rainwater may seep slowly away. This will prevent water from becoming stagnant in the hole. Make sure that the top edge of the liner finishes just below the existing soil level.

Cover the holes with a 5 cm (1 in) layer of gravel or pea shingle to ensure that they do not become blocked with the planting soil.

3. Install a Seep Hose

Set up a seep hose to ensure that the soil remains moist during the dry summer months. You can do this by sinking a perforated, rigid pipe into the bed. Block the base of the pipe and then cover with a layer of gravel to prevent the holes from becoming blocked with soil. Make sure that the top of the pipe remains above the soil surface. It can then be connected to a hosepipe for quick and effective watering.

4. Add the Planting Medium

Fill the hole with the topsoil (do not use sub-soil) mixed in with some garden compost or potting compost. If you want to create conditions for acid-loving plants, fill the hole using a compost with a low pH and enrich it with fibrous organic material. Reduce moisture loss by adding a deep mulch layer of coarsely sieved organic matter.

4. Plant Up

Plant up with area with moisture-loving plants, such as Japanese irises, Asiatic primulas, ferns such as onoclea (beard fern) and osmunda (flowering fern), and the large-leaved species Gunnera manicata (giant rhubarb) and Rheum palmatum (Chinese rhubarb).

It is usually best to plant in mid to late spring, using the same method that you would use for planting elsewhere in the garden. However, the area should be thoroughly soaked afterwards and kept moist, but not waterlogged, at all times. If you are growing any invasive species, such as Variegated reed grass (Glyceria maxima 'Variegata') you should confine them to a sunken container to prevent them from crowding out other plants.