Armoracia aquatica

Scientific name: Armoracia aquatica

Family: Brassicaceae

Usual maximum size in aquariums: 0 - 8 cm (0 - 3.15 inch)

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Recommended pH range for the species: 5.5 - 7.2

Recommended water hardness (dGH): 12 - 18°N (214.29 - 321.43ppm)

0°C 32°F30°C 86°F

Recommended temperature: 18 - 25 °C (64.4 - 77°F)

Reproduction of the plant: Cuttings

Origin (in the wild): North America

How fast these plants grow: Normal

Recommended substrate: Fine gravel

Demands on lighting: Bright

Ideal placement in a fish tank: Foreground

Common Name

Lake Cress

Origin

Native to North America, primarily found in wetlands and along lake margins in the state of Ohio and surrounding regions.

Plant Environment

Note: Armoracia aquatica is not a true aquatic plant. It naturally occurs in marshy areas and along lake shores where it may experience shallow flooding. While it tolerates wet conditions, it cannot thrive fully submerged for extended periods. It is best suited for paludariums, marsh-style setups, or the margins of garden ponds.

Propagation

This plant is typically propagated via cuttings. While it does produce seeds, they are often not viable. Cuttings root easily, especially when the stem sections are placed in moist, nutrient-rich substrates. In the wild, detached stems help establish new colonies through vegetative reproduction.

Difficulty

Easy in suitable conditions—bright lighting, moist substrate, and excellent aeration. It is not suitable for standard aquariums due to its intolerance to long-term submersion.

Short Description

Armoracia aquatica, also known as Lake Cress, is a fragile wetland plant from the Brassicaceae family. It features thin, brittle stems and delicate leaves, which are prone to breakage. This fragility actually benefits the plant in its native habitat, as broken fragments often take root elsewhere. However, in cultivation, it is best treated as a marginal or paludarium species. Due to wetland habitat loss, wild populations of this species are declining.

Frequently Asked Questions

• Can Armoracia aquatica be used in aquariums?

  Not ideally. While it tolerates wet conditions, it does not survive long-term full submersion. It is best suited for paludariums, marsh setups, or as a marginal plant in garden ponds.

• What’s the difference between marginal and aquatic plants?

  Marginal plants grow at the water’s edge and tolerate wet soil or shallow flooding, while true aquatic plants can live fully submerged. Armoracia aquatica is marginal, not aquatic.

• Can this plant be grown indoors?

  Yes, but only in conditions that simulate a wetland or paludarium environment. Keep the roots moist and avoid complete submersion of the leaves and stems.

• Why is Armoracia aquatica sometimes listed as an aquarium plant?

  Misclassification. Some commercial sellers mistakenly list marginal or emersed-only plants as aquarium-suitable. In reality, this species will deteriorate underwater within days or weeks.

• Is Armoracia aquatica related to horseradish?

  Yes. It belongs to the same plant family (Brassicaceae) and shares similarities with Armoracia rusticana, the common horseradish. However, it is not typically used for culinary purposes.