Container Gardening – Water Garden Pond
Planting Aids for Your Water Garden Pond
It is a good idea to plan ahead for a a plant-friendly design when building your pond. This will mean creating as many different planting opportunities as possible for pond plants. Even ready-made ponds which have not been installed in the optimal way can be improved later on.
If you want a proper pond floor in your pond, you can use various different materials, depending on the slope of the floor. Fine material, like sand and loam, should only be placed in the flat, marginal zone as it will begin to slide even on a very gradual slope. Do not rely on the plants’ roots holding on to the material of the pond floor. The finer material will have slid down to the deepest parts of the pond long before the root system has become dense enough. The best material for a shallow marginal zone is a sandloam-gravel mixture. This nutrient-poor material should be placed in the pond to a thickness of about 10 cm (4 in). The material should be inserted right up to the edge of the pond along the outer edge of the marginal zone so that no water can be seen. A mixture of a little loam and many stones is suitable for the pond floor in the shallow water zone. Place a layer of at least 5 cm (2 in) on top of the pond liner. Very steep banks can be designed with the help of a drystone wall.
Drystone walls for steep banks
If the marginal zone borders on a steep bank, there is always a risk that the pond floor material will slide down into the depths of the pond. A drystone wall will support the floor of the marginal zone and camouflage the pond liner all in one. In time, as their rhizomes find a hold on it, plants from the marginal zone and the shallow water zone will colonize the drystone wall. In the case of a ready-made pond, first drain the water.
- Acquire a few natural stones, 10-20 cm (4-8 in) in diameter, from a quarry or gravel works, along with a few larger blocks with a diameter of about 35 cm (14 in).
- Do not trample on and the edges of your pond when installing the stones. Nor should you run your wheelbarrow across the pond liner. A helper should be available to hand the stones and other items to you across the diner.
- Lay the largest stones in the deepest place. Play with the positions of the stones until they are all firmly slotted together.
- Stack further, smaller stones in the gaps (never lay large stones on top of small stones).
- In this fashion, gradually build a wall up to the top edge of the steep bank.
- Finally, use large stones to support the floor of the neighbouring marginal zone.
Containers as planting aids
Steep banks can be covered with plants quite easily if you use plant containers that can be hooked into the bank or placed on the floor of the pond. Alternatively, use verge matting for planting.
These boxes are suitable for a pond which has been built in an old swimming pool or is flanked by a patio. They are fitted with attachments like those for balcony boxes, which are hooked into the bank in such a way that they are covered by the water. Anchor the fixtures with special dowels on the outside of the pond or on the inside of the wall.
Plant containers can also be installed as “islands” in the centre of the pond. Use U-shaped building stones as pedestals. (These can be acquired from builders’ merchants.) Pad the pond liner with an extra piece of liner (folded to three thicknesses), before standing a U-shaped building stone on the bottom, in order to prevent any damage to the pond liner. The depth at which the container should be immersed in the water will depend on what plants you choose.
Basically, this consists of loose coconut matting with pockets for inserting plants. It is fixed to the edge of the pond with special dowels which can usually be purchased together with the verge matting.
The pockets of the matting should be filled with a nutrient-poor sandloam-gravel mixture. Suitable plants can be inserted into this loose weave both above and under the water. Marginal plants which form rhizomes are particularly suitable.
Laying the pond liner along the edge of the pond
In many garden ponds, the pond liner ends up lying flat on the ground at the edge of the pond. It is much preferable, however, to have the edges of the liner curling up vertically.
Pond liner which is left flat
This simply merges the edge of the pond and the marginal zone. During a drought, the plants along the edge of the pond will absorb a great deal of water from the pond and the marginal area will often end up drying out completely at such times. There may be considerable fluctuations in water level and few marginal plants can cope with such changes in moisture levels.
Pond liner which is curled up vertically
If the water level is not allowed to fluctuate too much, you will have the choice of a larger selection of plants for the marginal zone. This also means that there will be no merging of the marginal zone and the edge of the pond. Dig awayvertically to one spade’s depth along the edge of the marginal zone, so that the pond liner stands upright along the edge. The pond liner should end at the same level as the edge of the pond. It can be camouflaged with stones.
Suggestions for Planting in Containers
Plant containers make it possible to create islands in a pond.
They can also be used in a pond without a proper floor. Hanging boxes are also very practical.
A container of reed plants:
diameter about 1 m (40 in), in 20 cm (8 in) of water.
- 6 common reed (Phragmites australis), 10 bulrush (Scirpus lacustris), 6 mare’s tail (Hippuris vulgaris) or
- 5 reedmace (Typha latifolia), 10 bulrush (Scirpus lacustris), 3 reed sweet-grass (Glyceria maxima), 3 water soldier (Stratiotes abides).
diameter. About 80 cm (32 in), in 10 cm (4 in) of water.
- 3 lesser reedmace (Typha angustifolia), 4 common flag ( pseudacorus), 6 mare’s tail (Hippuris vulgaris), 3 bogbean (Menyanthes trifoliata) or
- 3 purple (Lythrum salicaria), 2 water plantain (Alisma plantago-aquatica), 3 marsh cinquefoil (Comarum palustre), 5 mare’s tail (Hippuris vulgaris).
about 1 m (40 in) long.
- Low-growing, cushion-forming planting: 2 marsh marigold ( palustris), 3 marsh forget-me-not (Myosotis palustris), 3 brooklime (Veronica beccabunga), 5 creeping Jenny ( nummularia), 3 bogbean (Menyanthes trifoliata).
- Medium high planting: 3 cotton grass (Eriophorum latifolium), 2 globeflower (Trollius europaeus), 5 blue iris (Iris sibirica), 3 marsh cinquefoil (Comarum palustre), 3 bogbean (Menyanthes trifoliata).
- Tall planting: 3 common flag (Iris pseudacorus), 1 tufted sedge (Carex elata), 2 water plantain (Alisma plantago aquatica), with 5 marsh forget-me-not (Myosotis palustris).