Watercress (Nasturtium officinale)

Watercress (Nasturtium officinale) is a fast-growing, aquatic or semi-aquatic perennial herb in the Brassicaceae family. Native to Europe and Asia, it's cultivated for its peppery, nutritious leaves and stems—a classic salad green and superfood.

Description

Trailing, mat-forming stems root at nodes, growing in shallow water or wet soil. Leaves are pinnately compound, 3–9 small, oval, dark green leaflets. Stems are hollow. Small, white, 4-petaled flowers in clusters. Entire plant is edible, best harvested before flowering.

Growing Conditions

• Zones: 3–11 (cool-season perennial; grown as annual in heat).
• Light: Part shade to full sun (prefers cool, shaded water).
• Water: Requires clean, flowing water 2–4 inches deep, or constantly saturated soil. pH 6.5–7.5.
• Soil: Rich, mucky, high organic matter.
• Temperature: 50–70°F (10–21°C); bolts in heat.

Care & Maintenance

Harvest by cutting stems above water line; regrows quickly. Propagate from stem cuttings rooted in water. Divide mats. Ensure water source is uncontaminated (avoid liver fluke risk).

Uses

Salads, sandwiches, soups, smoothies. High in vitamins A, C, K, calcium, iron. Medicinal uses. Aquaponics, stream-side planting, container water gardens.

Potential Issues

Must use clean water—commercial growers use tested springs. Snails, aphids. Bolting in warm weather. Invasive in some waterways—contain cultivation.

A peppery, nutrient-dense green that turns a clean stream into a salad bar.