By John_lisney
United Kingdom 
Why is my Acacia dealbata losing its leaves? Your web page does not really answer the question. Ours is a young tree, now about ten foot high, bought last summer and transplanted in a large pot to be brought into our unheated conservatory for the winter. It is now in full bloom, but is rapidly dropping its leaves.
In the recent cold snap the conservatory dropped to about -2 degrees C for a couple of brief overnight spells.
29 Feb, 2012
Most likely the shock of the sudden drop in temperature after a relatively mild winter in your unheated conservatory. This assumes you've kept up with the watering as and when necessary. If it is just that, the plant should recover gradually.
29 Feb, 2012