Good drainage and the right site can make all the difference between success and failure for these marginal plants.

"Without any snow on the ground, any marginal plants are going to have frostbitten toes," he wrote in an e-mail message.

It grows as a marginal plant in up to about 15cm of still or slow-moving water.

It is also suitable for a bog garden or as an aquatic marginal plant.

In addition to supporting aquatic and marginal plants, it supports a population of water voles and breeding waterfowl.

Some marginal plants have hollow stems and if these are cut so severely that water can enter, they rot away.

The structure is concrete lined, which prevents growth of marginal plants, however this does not prevent the reservoir attracting varied waterfowl and other birds.

Vegetated berms containing marginal plants have been placed along the banks.

Lily leaves should be cut cleanly, not pulled: this applies equally to marginal or bog plants.

Magpies also use marginal plants to watch for fish.