Bryan McAllister’s personal reference notebook
July 30, 2026Short & citedBlog
Civic Viewpoint.
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Kept by Bryan McAllister — short guides, clear facts, and the Canadian angle when it matters.
Field Notes • Plant

Watercress

Watercress is an aquatic or semi-aquatic flowering plant in the mustard family, Brassicaceae, usually identified as *Nasturtium officinale*.

Updated July 30, 20261 min readCited sources

Watercress is an aquatic or semi-aquatic perennial herb in the mustard family, known for its peppery, edible leaves. It is one of the oldest leaf vegetables used by humans.

What it is

Watercress (*Nasturtium officinale*) is a fast-growing plant with hollow stems, small round to oval leaves, and white flowers. It belongs to the Brassicaceae family, alongside cabbage, kale, and mustard greens.

Where it grows

Native to Eurasia, watercress thrives in cool, clean, slow-moving freshwater like springs and streams. It has naturalized in many regions, including North America, where it is both cultivated and found wild.

How it is used

The leaves and stems are eaten raw or cooked, adding a sharp, peppery flavour to salads, sandwiches, and garnishes. In Canada, it is grown commercially in water beds and sold as a culinary green.

In short

  • Watercress is a perennial aquatic plant in the mustard family.
  • It grows in clean, cool, flowing freshwater.
  • Its leaves are edible with a peppery taste.
  • It is cultivated and naturalized worldwide, including in Canada.
Canadian angle

Watercress is grown and sold in Canada as a culinary leafy green, and it is relevant to Canadian readers as both a food plant and a freshwater species that can become naturalized outside its native range.

Quick questions

What is watercress?
Watercress is an aquatic edible plant in the mustard family, usually identified as *Nasturtium officinale*.
Is watercress edible?
Yes. The leaves and stems are edible and commonly eaten raw or cooked.
Where does watercress grow?
It grows in cool, clean, slow-moving or running freshwater such as springs, brooks, and streams.

Sources

  1. Wikipedia — https://en.wikipedia.org/wiki/Watercress
    Supports: Scientific name, family, native range, and status as an old leaf vegetable.
  2. U.S. Forest Service — https://www.fs.usda.gov/wildflowers/plant-of-the-week/nasturtium_officinale.shtml
    Supports: Aquatic/semi-aquatic habit, habitat, worldwide distribution, and mustard-family classification.
  3. Missouri Department of Conservation — https://mdc.mo.gov/discover-nature/field-guide/watercress
    Supports: Perennial aquatic growth form, native Eurasian origin, edible use, and invasive status in some regions.
  4. Encyclopaedia Britannica — https://www.britannica.com/plant/watercress
    Supports: Perennial aquatic plant, native to Eurasia, naturalized in North America, edible young shoots and leaves.
  5. CABI Compendium — https://www.cabidigitallibrary.org/doi/full/10.1079/cabicompendium.35646
    Supports: Taxonomy, habitat preferences, and commercial cultivation details.
  6. Plants For A Future — https://www.pfaf.org/user/plant.aspx?latinname=rorippa+nasturtium-aquaticum
    Supports: Edible leaves, peppery flavour, and nutritional uses.
  7. ScienceDirect Topics — https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/watercress
    Supports: Two-species treatment, cultivated crop status, and growth/cultivation conditions.