I've used Crepe Myrtle in a 65 gal. hardscape. Its safe. Here's a pic. The Crepe Myrtle branch is the thicker long branch, weighted down by a big rock. The rest of the DW is old dried out Red Bud tree branches. It takes a long time to water log.
Awesome, thanks for your reply, I appreciate it, also nice scape.
Question, did you mean the red bud takes a long time to get water logged or the crepe myrtle?
Typically, most hardwoods are safe. NO conifers. I have maple, madrona and alder branches in my aquariums. I add alder cones to my shrimp tank that I collect from the woods behind the house. I also add oak or magnolia leaves to my SA tanks.