Today I gave the ludwigia palustris its first trim. A couple of the stems were just under the surface so I clipped off the three tallest. This ludwigia, in contrast to some reports, doesn’t have very many aerial roots but where there were a few part-way down the stem, I trimmed to just above the node below the roots to allow (hopefully) new growth, then clipped off the stem to just below the node where the roots are and planted those pieces on the far left of the tank in a region that was more thinly grown, very likely due to less light off to the side and in the shade of the taller stems in the centre.
I was following this guide to trimming stem plants from dw1305 so we’ll see how that goes. Seems straightforward and reasonable. There was some question as to whether the shrimp would just immediately dig up the newly planted tops, but happily that hasn’t happened yet.