A retired arborist friend of mine stopped by, and when I complained about some of my oldest fruit trees looking poorly, he recommended "root feeding" with sort of a giant hypodermic needle that forces fertilizer and water deep underground. He said he used this technique up north and it quickly rejuvenates fading old trees. We rode around town to various stores and nurseries, looking for a root feeder, but to no avail. Before I go to the trouble of ordering one online, I thought I'd seek opinions here.