Watercress (Nasturtium officinale)
Edible! Yes, this is the famed peppery, spicy watercress of British trim-the-crust-off watercress sandwiches, but it is also so much more! We don't usually showcase edibility before even describing the plant and the bloom, but watercress is worth putting the nutrition before the bloom...everyone should be eating this plant, and why not let your water feature also be your vegetable garden?
Watercress is known as being nutrient-dense, but did you know that it was listed as the most nutrient-dense food by both the Aggregate Nutrient Density Index and the CDC--watercress was the only food to receive a perfect score by both. A cruciferous vegetable related to broccoli (known for its cancer-fighting phytochemicals), watercress may also boast a higher essential mineral content than any other plant.
Watercress tends to be a short, creeping/spreading plant, although in shade or when crowded it can get fairly tall by midsummer. It can be grown as a regular garden plant if it has constant moisture, but in hot conditions watercress does best in shade and the shallow running water of a streambed. Rather than planting it in water, it is best to plant along the edge of the streambed or pond and let it grow into the water. It generally keeps some live leaves and/or stems down to Zone 7; in the colder zones it may die completely and reseed itself in Spring (seeds need to germinate out of water, at the pond edge).
Because watercress likes cool weather, it grows well in Spring and acts as an excellent filtering plant, helping keep the pond clean. Spring is also the best time to harvest leaves and stems for salads, soups and stews (and sandwiches!)--once the clusters of small white flowers appear in Summer, leaves can have a bitter flavor. Plants may be trimmed back to encourage new growth and delay flowering; this keeps plants fresh loooking and extends harvesting.
Native to Eurasia and Asia but naturalized all over the US, to the point that most people consider it to be native.
We recommend buying watercress in Spring to reduce plant stress from shipping in hot weather, especially in warm summer climates. We may ship plants in Spring as rooted cuttings or in small pots, depending on availability; in Summer, we ship only in small pots as plants handle shipping in hot weather better in pots. Watercress leaves also tend to turn yellow in shipping during the warmer months, but quickly recover so long as they have a good stem and root system.
Minimum purchase of 3.
Hardiness Zone: 3-10
Planting Container: We recommend a 4" Planting Basket or a 1 Gallon Economy Planting Container.
Light Requirements: full sun to part shade, depending on climate; in warm climates, use shade and running water
Height: 6"-15" - Spread: 24"+
Water Depth: Moist soil to 3" moving water in streambed (Maximum water depth is for mature plants)
For planting instructions see our: Planting Instructions for Bog Plants Page.