Hey, we hate gardening as much as the next guy, but even if you don't know secateurs from scissors, you need to take a look around once in a while and make sure your garden isn't taking over your home!
We noticed this on a recent drain job. The tree had grown up between the tank and the outlet line going to the house. A few more months and it would probably have busted the fitting causing a pretty large leak. If you see something like this at your house, don't try to wrench the tree out because you might bust the pipe. Just cut the tree off at the base and leave the tree to wither. Once it is loose, you can remove it. If you're not comfortable with any issues you are having with your hot water system, you can always ring Good Neighbour Plumbing on 9651 4884.