Most of the great rhododendron gardens of the world have water features. Valley Gardens near Windsor has Virginia Water, Bodnant in North Wales has a rushing mountain stream in a spectacular rock gorge, and the gardens of Scotland and Ireland have water all over the place, mostly coming down in sheets. These water features are typical of the mountainous environment where rhododendrons grow in the wild.

Very few of us are blessed with a natural water feature in the garden but it is not that difficult to create a pond that works well in a rhododendron garden. Most references on garden ponds, however, focus on pond plants and fish. A pond choked with aquatic plants does not work so well for a rhododendron setting where it is effective to create cool, calm reflective surfaces to contrast with rhododendrons.

Site selection is critical to achieve a natural-looking landscape. A pond should be sited at a low spot, and if you construct a stream, it should be located in a small valley. It is surprising how often this fundamental rule is disregarded.

Ponds and streams for a rhododendron garden are most easily constructed to any desired shape using a flexible rubber liner laid over sand and fabric to reduce the risk of puncture. The key to successful pond construction is to plan the edge treatment beforehand.

A rock-lined pool is one of the most effective designs and this is achieved by constructing a level shelf around the edge of the pond. The liner is cut to extend several feet beyond the shelf. Large rocks are placed along the shelf to form the edge, and the liner is folded up behind the rocks. Soil is backfilled behind the liner up against the rocks keeping the liner vertical. When the pond is filled, the water level is about six in. above the base of the rocks resulting in a natural look.

As the pond will be at a low spot, drainage around the pond is likely to be required to avoid the soil around the pond getting soggy. Installing drainpipe and drain rock all around the pond solves the poor drainage issue.

It is worthwhile building a small stream into the pond as the circulation of water keeps the main pond clear of algae. Use a submersible drainage pump to power the stream rather than the more expensive pumps sold specifically for ponds. Streams are constructed by forming small ponds with intervening small waterfall steps. The liner is overlapped from one pond to the next over the steps and rocks are placed to cover the liner to achieve a natural look.