Propagating Alternanthera reineckii 'Lilacina' from Cuttings

How to propagate the purple-leaved Alternanthera reineckii 'Lilacina' by cuttings, with light, CO2 and iron tips to keep the warm red coloration strong.

Overview

Alternanthera reineckii is an aquatic plant in the family Amaranthaceae, native to South America, where it populates submerged and semi-aquatic habitats such as marshes, stream banks and ponds. Several cultivars are grown as ornamental aquarium plants, and 'Lilacina' is one of them — a broad-leaved form with a brownish-purple top and a reddish underside used for warm color contrast in the midground.

Because 'Lilacina' is a clonal cultivar, it does not come true from seed; the only reliable way to multiply it is vegetatively, taking cuttings that carry the parent's exact leaf shape and color.

Propagation Method (Cuttings)

Like all stem plants, Alternanthera can be propagated by cutting off the top few centimetres of a stem and planting it directly into the substrate; new buds and roots then grow from the internodes. Once a plant gets tall enough you can prune off the tops and replant them for easy propagation.

Step-by-Step

1. Choose a healthy, well-colored stem and cut the top 5–10 cm with clean, sharp scissors.
2. Strip the leaves from the lowest 2–3 cm of the cutting so they will not rot under the substrate.
3. Plant each cutting deeply, at least a few centimetres into the substrate, spacing them out rather than burying a single dense bunch.
4. Leave the trimmed base in place — it will send out side shoots that thicken the original clump.
5. Mature stems that have already produced side shoots can also be cut off and replanted once they are a few centimetres in size.

Conditions for Healthy Growth

'Lilacina' is among the easiest red Alternanthera to grow and does fine in low-tech tanks, but coloration improves dramatically under high light, fertilizers and extra iron. CO2 injection helps overall growth and the plant tolerates very strong lighting — around 100 PAR will not burn the leaves.

Trimming & Maintenance

When the bottom stems stay healthy you can trim a clump once, twice, even three times. After about three trims it is generally time to replant: cut and replant the colorful tops and discard the old stems and roots to refresh the group.

Common Challenges

The most common problem is loss of red color and deterioration of shaded lower leaves. Low light or low iron pushes the plant green; thinning the clump, raising iron and light, and replanting tops when lower stems decline keeps the warm purple-red tone.