Rotala rotundifolia don't branch after trim

[flygja]

I've got a bunch of Rotala rotundifolia that don't branch (2 branches from the trimmed stem) after they are trimmed. Does anyone know why this is so? Is it due to a lack of light or nutrients or CO2? Here's a picture of the stems, I didn't take a close up shot.

IMG_20141208_092720 by flygja, on Flickr

The stems have been trimmed 4 or 5 times now, but as you may be able to see, they don't branch and bush up at all. Would appreciate any comments on this.

 

[Mick.Dk]

Rotala rotundifolia covers a very, very wide variation of plants. Variations or sub-species.
I have tested several, variating in leaf-shape, colour-intensity or colour"temperature"(more or less red, yellow, purple or pink in it), growth-pattern (up-right, spreading or creeping-"ish")......... and some are branching more willingly, than others. All under exactly same conditions.
Different conditions will influence a lot on all aspects, ofcourse. Not all "types" are equally virile, either.
Your plants look healthy regarding both colour and leaf-shape - so I really don't think light or fertilizers are the issue
- an old trick, that you likely know allready, is to let stems grow to surface and "flatten out", just under it. This usually promote more branching (and aerial roots). When branched you can then cut the tops and replant in the group.......

 

[parotet]

Is high GH another myth in that case? There's plenty of places where poor branching and regrowth is related to very hard water

Jordi

 

[Mick.Dk]

In my experience, Rot. rotund. is a very tolerant and forgiving plant, capable of growing in very different conditions.