Q.  I have a Cordyline in my yard, I didn't plant it, it just appeared and grew so I'm not sure what type it is.  It's mainly green but of late it's turned a light green/yellow.  It's been growing steadily for the past 5 years and it's around 2m tall.  Just of late it's been loosing a number of leaves, do these plants loose leaves?

A.  Cordylines have a survival mechanism in the form of a tuber, this tuber can survive bushfires and drought and grow again years later when the conditions are right.  Although Cordylines love water in the warmer months they must have good drainage, if the ground becomes too waterlogged the tuber will rot and they will die.  Old leaves will naturally yellow and fall off in winter but a combination of too much water and cold weather could make the yellowing worse than normal.