There is nothing I know of that you can't add too much of, just as far as growing power goes. I tried different amounts of alfalfa and asked around about how much was too much, but never found an answer ( not taking into consideration the attraction of critters). The same I think might be said of Milorganite, but the smell might be too strong before nitrogen value got too strong. It will be interesting to see if anyone has ever applied too much and burned any daylilies. I know there are limits, and would love to know what they are.