rockm

"do bonsai ever just die of old age? given proper feeding pruning repotting etc, would it be possible to keep a bonsai alive forever? this may sound a bit utopian but it intrests me."

Interesting question. Nothing really dies of "old age." Plants and animals are usually killed by disease. Plants, in theory, can live forever, as they regenerate themselves every year or so. As they age in the wild, though, they reach physical limits of their ability to function--roots get less and less efficient, upper growth extends to the limits of the tree's ability to nourish it.

In bonsai, we limit the amount and subsequent stress, of all that extension growth. We renew the root system every few years with hard pruning, forcing the tree to push more efficient feeder roots.

As for older trees requiring special care---the one I have really doesn't. I have a collected live oak that is probably well over 100 which is somewhere in mid-adulthood for the species. It is repotted every four years or so. It has been in a container for almost 15 years. It is more vigorous now than when I got it six years ago. I feed it as I do my other trees in the late stages of development.