This plant has no doubt come into Australia by seed so it should not be called ‘Big Swing’ as it is in the U.S.
It grows about twice the size of sagittata and therefore has twice the flowers. It doesn’t like frost which means the size gets restricted during cold winters. In warmer areas it might be more than a metre high and enlarge its area by layering and suckering. It is such a gorgeous blue that I don’t think you could get mad with it expanding its area but it is possible.
Macrophylla X sagittata should grow well in part shade. It frost burns under -2C.
It propagates easily by cuttings.