Originally Posted by john_ny

I would say almost any tree or shrub is rootable to some degree. With some, maybe semi hard growth is better, and you may have to use a rooting hormone. I have never done guavas from cuttings, but have done apples, peaches, and citrus. A probable more certain way to do it would be to layer it. If you have a branch that is close enough to the ground, dig a little trench, scrape the bark, and apply rooting hormone, bury the portion of the branch, and put a brick or something over it, to make sure it doesn't pop up. If there isn't a branch close enough to the ground, you could place a pot under the plant, and bury the branch in that, or you could air layer it. Scrape a branch, apply hormone, cover with damp peat moss, and wrap with plastic, or tin foil.