IME with Kenya tree, you don't really have to do anything at all. They seem to prefer much less than pristine water conditions, grow rapidly, and reproduce by dropping branches that will settle into whatever new place they land. When I tore down my old 150DT/120fuge/50sump system, what had been one kenya tree in the refugium had become, within just a couple years, at least 100 kenya trees in all three tanks, having been able to survive a trip through my DART return pump to end up everywhere.