Propagating Cardamine lyrata 'Japan' from Cuttings

How to propagate the compact Japanese cress 'Japan' by node-rooting stem cuttings, with the cool, slow-moving water and bright light this climbing round-leaf plant prefers.

Overview

Cardamine lyrata 'Japan' is a compact Japanese form of Cardamine lyrata, an aquatic member of the mustard family (Brassicaceae) native to the marshes of eastern China, Siberia, Korea and Japan. It is also known as Japanese cress and Chinese ivy. The 'Japan' selection carries smaller, rounder leaves on a climbing stem and is grown vegetatively to keep that compact habit.

The species grows rapidly under good conditions and forms an attractive, bushy plant. Because it propagates easily by cuttings, the cultivar is multiplied entirely from stem pieces rather than seed.

Propagation Method (Cuttings)

Cardamine lyrata propagates easily by cuttings. The stem roots from its nodes, so a cut section replanted in the substrate readily develops new roots and continues growing, while the base sends out side shoots.

Step-by-Step

Select a healthy stem with several leaf nodes.
Cut the top 5-10 cm just below a node, where rooting is strongest.
Strip the lowest leaves to expose one or two bare nodes.
Push the bare nodes gently into the substrate so they can root.
Keep the base planted; it will branch into new shoots over time.

Conditions for Healthy Growth

As an aquarium ornamental, Cardamine lyrata needs a supply of cool, slow-moving water and strong light. It suits coldwater and subtropical scapes and tolerates a wide hardness range. High levels of carbon dioxide speed growth, though CO2 is not strictly required.

Lighting: medium to strong; brighter light keeps the form compact.
Water: cool and slow-moving; temperature 15-26 C and not exceeding about 28 C.
CO2: optional; added CO2 speeds growth.
Substrate: any; pH 6-7.8; GH 4-16.
Difficulty: beginner-friendly.

Trimming & Maintenance

Trim about every two weeks to keep the bushy form and prevent the climbing stems from sprawling. Each trim provides ready cuttings. The plant can grow emersed as well as submersed, and its emersed growth is robust; for the aquarium it is kept submersed. In open ponds keep water below roughly 28 C.

Common Challenges

Leggy, stretched stems under weak light.
Decline in water that stays too warm above about 28 C.
Sprawling growth if not trimmed regularly.
Slow establishment if cuttings have no intact node to root from.