Nasturtium officinale

Watercress has peppery leaves, which are commonly used in salads and soups. Although more used to growing wild in flowing streams, watercress can easily be raised in a container or garden pond – as long as its feet are kept wet and the water is replenished every week, you should be able to harvest watercress all year round.

Sow seeds on moist compost in spring, and plant out young plants when all risk of frost has passed. If growing your watercress in a pot, make sure it's sitting in a tray of water. Alternatively, grow plants in an aquatic pot and place this in the shallows of your pond.

Avoid harvesting watercress from the wild as plants may be harbouring liver flukes, which can be damaging to human health.