Propagating Didiplis diandra by Cuttings

How to propagate the fine-leaved water hedge Didiplis diandra by cuttings, pulling and replanting tops to keep the stems healthy and the upper foliage red.

Overview

Didiplis diandra, the water hedge, is the only species in its genus, a member of the Lythraceae family native from the southeastern USA to northeastern Mexico. It is a delicate stem plant with fine, narrow leaves; under intense light the upper half of each stem develops pinkish to red foliage, and strong light close to the plant or sunlight can push it to a blood-red colour.

It is a fast grower, advancing roughly half an inch a day in good conditions. Its readiness to grow and branch makes cuttings the standard way to multiply it.

Propagation Method (Cuttings)

Water hedge is propagated by cuttings, but maintenance and propagation are best combined: rather than only topping, you periodically pull the entire plant, cut the bottoms off, and replant the healthy tops. This refreshes the planting and yields cutting stock at the same time.

Step-by-Step

1. Lift the plant or select healthy stems and cut the top 5-8 cm, keeping the well-coloured upper portion.
2. Discard or compost the worn lower stems, which lose vigour over time.
3. Strip the lowest leaves to bare a node, handling the fragile stem gently to avoid crushing it.
4. Replant the tops into a sandy upper layer over nutrient-rich substrate so they slide in without breaking.
5. Provide strong light and ample CO2 so the cuttings root quickly and colour up again.

Conditions for Healthy Growth

Strong, close light is essential — far from the light the plant stays green, while intense light or sunlight brings out the orange-to-red tips. CO2 is especially important for a reddish plant like this, and Didiplis prefers softer water. A nutrient-rich substrate topped with sand suits both its roots and its fragile stems. It also grows emersed, which can be used to build up healthy stock.

Trimming & Maintenance

Because it grows fast, trim often — roughly every ten days. Don't simply top it indefinitely: from time to time pull the whole plant, remove the bottoms and replant the tops, which prevents the lower stems from declining and keeps the stand dense and richly coloured.

Common Challenges

Under low light the lower stem really suffers and over time can rot away until the top breaks free, so insufficient light is the main pitfall. The fragile stems also break easily when planted into hard substrate. Keep light high, CO2 generous and water soft to maintain both health and red colour.