Rotala Growing Short, Dense, Small And Slow.

I have a Rotala Rotundifolia for several months and after dropping off the old leaves and stems, many new growth came off the base that stay small in leaf size,and dense. Instead of growing tall as a stem plant, it looks more like a ground hugging carpet plant. The leaves also turn more green than pinkish when I first got it from nursery grown plant.

I have a 75 gal with CO2 injection and 110 watt led, estimated to be medium light or around 50 par at the substrate level, based on Rotala calculator. I grow mostly low light Anubias, java fern, and Buce and they are doing fine, coming up with new leaves every week.. Rotala Rotundifolia and Ludwigian repen are the only two stem plants that I tried and survived, but both grow very slowly.

Is it a sign that my light is not sufficient for stem plants?

 

To grow stem plants heavily like yours, I believe I need to double my light intensity. So I concentrate on low light plants, and R. rotundifolia and L. repen are at the low end spectrum of stem that survived in my set up. Other stems I tried just melted away.

So you can have either all high light stems, or all low light Fern, Buce and Anubias, but you can't have both and be happy.

I didn't top off the old plants, they self pruned and fell off . But new shoots sprout from the base, and now it looks more like a baby tear. My L. repen doesn't behave the same though, just grow slowly. When I read the journal of Greggz, some stems are so fast growing that they have to be topped frequently. It's not a problem for me, which may be the positive aspect.