Propagating Aponogeton boivinianus (Tuber Division and Seeds)

An advanced guide to propagating the bullate-leaved Madagascan Aponogeton boivinianus by dividing its tuber and by raising true seeds from flowers that rise above the surface.

Overview

Aponogeton boivinianus is a Madagascan species in which a rosette of broad, elongated, strongly bullate (indented) dark green leaves arises from a round, flattened tuber. It reaches about 60 cm and prefers rather cool, very clean water and a good substrate. It is a heavy root feeder and an advanced plant to keep and propagate.

Unlike many of its relatives, A. boivinianus rarely if ever goes fully dormant, but its growth still benefits from a rest period. Propagation works through the storage tuber and through true seeds, since the flower spike can reach the water surface.

Propagation Method

There are two routes. The first is tuber division: most Aponogeton species reproduce by splitting the bulb, so a large tuber bearing more than one growth point can be cut into pieces. The second is seeds: the plant often flowers on a long spike that reaches the surface, and propagation is from seeds.

Step-by-Step

For tuber division, lift a large, healthy tuber that shows more than one growing point or sprout.
Cut the tuber so each piece keeps a growth point and some roots, then replant each piece in rich substrate with the tuber barely covered.
For seeds, let the flower spike grow up to the water surface and flower in the open air above it.
Pollinate the open flowers (for example by hand) and let seeds set on the spike.
Sow the ripe seeds and grow them in a warm, damp, fine substrate until small plants form.
Pot up the young plants once they have leaves and roots.

Conditions for Healthy Growth

Rich, good substrate for this heavy root feeder, with the tuber barely buried.
Very clean water and rather cooler temperatures than most tropical plants (about 20-27 C).
Soft to moderately hard water around neutral pH.
A rest period to keep the tuber vigorous over time.

Maintenance

Keep the water clean and the substrate rich, and remove decaying leaves so they do not foul the water. Allow the plant a rest period so the tuber can recharge its reserves, then it will sprint into new growth. Only divide a tuber that is clearly large and multi-crowned.

Common Challenges

Tuber rot if pieces are cut without a healthy growth point or are buried too deeply.
No seeds when the flower spike cannot reach the surface or the flowers are not pollinated.
Stalled growth in poor substrate or warm, dirty water, since the species wants clean, cooler water and rich feeding.