Nasturtium

These hardy, aquatic perennials are natives of Asia and Europe and are naturalized in North America. They are found growing in cool, flowing streams. N. officinale, the Watercress, forms mats of glossy green leaves that are divided into many leaflets and rounded clusters of white, four-petaled flowers from March to November. The leaves of this plant have a peppery taste and are used in salads and as garnishes. Nasturtiums can be grown on the edges of ponds, in streams or waterfalls.

Pot Cultivation

Nasturtiums can be grown in one-gallon containers or larger, filled with rich garden loam. If the container is going to be set in fast moving water, cover the surface with a good layer of gravel to keep the soil from washing away. These plants can also be grown in a bed of gravel in a stream or waterfall. These plants will go dormant in the winter but return the following spring. Watercress will grow almost as well in moist soil, in light shade as in flowing water. Watercress will survive the winter in flowing water but can freeze in containers or in the garden, so keep the soil constantly moist and lightly shaded. The soil pH should remain close to 7.0 and very fertile. The soil may be dug out up to a foot deep and well-decayed manure mixed into the bottom. The surface of the soil is then covered with a thick layer of sand. The plants should be spaced 12 inches apart. They also do fine in 5 to 7 gallon containers with drainage holes, such as a plastic basin. Set the container in a large saucer and water plants from the bottom, but don't let water stand in the saucer. Watercress will endure frequent but not severe cutting back. Snip off tips beyond where they set anchor roots.

Propagation

Start from seeds or from stem cuttings of fresh Watercress sprigs rooted in water. Both ways are easy and fast. Soak the seeds for 12 to 24 hours before planting. Thin the plants to 12 inches apart. They can also be increased by dividing the roots.