As the name suggests these marginal pond plants grow along the poolside usually in aquatic planting baskets. These plants provide splashes of colour throughout the growing season. Certain plants, such as Veronica Beccabunga, will raft across the water offering shade for the fish, reducing sunlight levels and thus hindering the growth of algae. Many of the grasses are especially useful for removing excess nutrients from the water and have a wide range of variegated foliage to give colour throughout the season. Some plants, such as Caltha Palustris are ideal for an early display of colour. There are also excellent spreading plants such as Mimulus, which will quickly fill the top of a basket, making it a suitable companion for a tall plant, such as an attractive iris.
Careful thought should be put into the positioning of marginal plants, ideally placing the tall grasses, iris's and rushes at the back of the pond while keeping the plants which tend to spread and raft at the front of your display.
How To Plant
These plants are generally sold either as immature plants in small pots or more mature plants in small aquatic baskets. It is recommended to replant all these into larger baskets. Plants such as tall Iris's and grasses will need a deep large basket as they are prone to blowing over in the wind, and these deep baskets will provide some counter balance against the wind and plenty of room for root growth. Spreading and rafting plants can be planted into shallower baskets, but remember they will need plenty of room for growth, so it is always worth while replanting regularly to ensure the best possible display.
In wildlife pools it may be possible to plant directly into a pre-made planting area (See Edging a Pool). Should you wish to contain the growth of these plants in such an area it may still be worth considering sinking the plant in a basket to limit it's spread.