Thank you for the responses! I have java ferns wedged into a tree decoration and the light barely penetrates the rhizomes. As for applying super glue into the decor, I tried that, but the plant would come off if I move the decor. And tying it would be a pain for me.
I have some baby rhizomes near the light on the underside of mother leafs, as well as some windelov rhizomes in shaded areas... They both seem to be growing at the same rate, though I'm comparing baby rhizomes to more developed ones (not sure how they compare).... But they are both showing growth, so I guess it doesn't matter?