Krzysztof Ziarnek, Kenraiz / CC BY-SA 4.0 · Source
Watercress
Nasturtium officinale
Overview
A peppery, aquatic green that grows wild in clean streams across much of the world, watercress was recently ranked as the single most nutrient-dense food by CDC researchers. Its sharp, mustard-like bite comes from glucosinolates, making it both a culinary delight and a cancer-fighting powerhouse. Watercress has been eaten since Roman times and can be easily grown in containers with continuously moist soil.
Watercress (Nasturtium officinale) is a delightful addition to any garden, pond, or water feature. This aquatic plant belongs to the cabbage family, Brassicaceae, and is known for its vibrant green leaves and delicate yellow flowers that bloom in the summer months.
Native Range and Habitat
Native to Europe and Asia, watercress thrives in cool, shallow waters with good sunlight exposure. Its natural habitat includes freshwater streams, springs, and damp, shady areas near water sources. In the wild, watercress often forms dense mats on the surface of the water or grows along the edges of waterways.
Growing Conditions and Care
To cultivate watercress, ensure that your pond or water feature has shallow, cool water (around 60-70°F or 15-21°C) with a depth of no more than 6 inches. The pH level should be slightly acidic to neutral, ranging from 6.0 to 7.5. Watercress prefers full sun to partial shade and well-drained soil that remains moist but not soggy.
Watercress is incredibly versatile and has multiple uses:
Edible
Watercress leaves and young shoots are edible and highly nutritious. They have a peppery flavor and can be eaten raw in salads or cooked as vegetables. This plant was popularized by the Romans, who considered it a delicacy and often grew it near their water sources.
Medicinal
Historically, watercress has been used to treat various ailments, such as scurvy, digestive issues, and urinary tract infections. Today, it is still valued for its high vitamin C content and other beneficial compounds that may help boost the immune system and support overall health.
Ornamental
With its lush green foliage and bright yellow flowers, watercress can add a pop of color to your pond or water feature while also providing a valuable food source for aquatic creatures like fish and amphibians.
Ecological
Watercress plays an essential role in maintaining the balance of ecosystems near freshwater sources. It provides shelter and nutrition for various wildlife species and helps filter pollutants from the water, improving overall water quality.
Notable Varieties:
- Watercress (Nasturtium officinale): The standard variety, known for its bright green leaves and yellow flowers. - Broad-Leaved Watercress (Nasturtium microphyllum): A closely related species with broader leaves that prefers slightly warmer waters than the common watercress.
Uses
In summary, watercress is a versatile and useful plant that can enhance both your garden and your well-being. Whether you appreciate it for its culinary, medicinal, ornamental, or ecological benefits, this aquatic gem is sure to impress.
Growing Conditions
Habitat & Range
- Habitat
- Grasslands & Prairies
- Native Range
- Native to Alberta; also native to Afghanistan, Algeria, Austria and 55 more regions; introduced in 41 US states
- Cultivation Region
- Temperate regions
Botanical data via projectGAIA.
Companion Planting & Soil
Good Companions
Sowing & Propagation
Propagation Methods
Planting Calendar
When to sow, transplant, and harvest by growing zone.
| Zone | Action | Months | Notes |
|---|---|---|---|
| Cold (1-2) | Transplant | May — Jun | Transplant to stream edge or pot set in water tray; needs constant moisture |
| Cold (1-2) | Harvest | Jun — Sep | Cut stems above waterline; regrows quickly; best before flowering |
| Cool (3-4) | Direct Sow | Apr — May | Direct sow in very moist soil or shallow water; press seeds into surface |
| Cool (3-4) | Harvest | May — Oct | Harvest young shoots continuously; peppery flavor |
| Moderate (5-7) | Direct Sow | Mar — Apr | Sow in boggy soil or shallow water; roots from stem cuttings readily |
| Moderate (5-7) | Direct Sow | Sep — Oct | Fall sow for cool-season harvest |
| Moderate (5-7) | Harvest | Apr — Jun | Spring harvest; flavor turns bitter in heat |
| Moderate (5-7) | Harvest | Oct — Dec | Fall harvest |
| Warm (8-9) | Direct Sow | Sep — Nov | Fall through winter crop; bolts in spring heat |
| Warm (8-9) | Harvest | Oct — Mar (wraps) | Harvest through cool months |
| Hot (10+) | Direct Sow | Oct — Jan (wraps) | Cool-season only; grow in shade with standing water |
| Hot (10+) | Harvest | Nov — Feb (wraps) | Winter harvest; must have constant water |
Uses
Culinary
- Peppery addition to salads, sandwiches, and soups
- Classic watercress soup (potage au cresson)
- Blended into pesto and compound butters
Medicinal
- Ranked #1 most nutrient-dense food by CDC nutrient density score
- Rich in glucosinolates with anti-cancer properties
- Extremely high in vitamins K, A, and C
Other Uses
- Aquatic or bog garden edible plant
- Natural water purifier in stream-fed systems
Safety Notes
Whilst the plant is very wholesome and nutritious, some care should be taken if harvesting it from the wild. Any plants growing in water that drains from fields where animals, particularly sheep, graze should not be used raw. This is due to the risk of it being infested with the liver fluke parasite[5, 244]. Cooking the leaves, however, will destroy any parasites and render the plant perfectly safe to eat[244]. May inhibit the metabolism of paracetamol [301].
