It sounds as if you are mistaking mimosa for false acacia and also the sensitive plant.
Mimosa is blooming now and that is what you can smell. The sensitive plant is a house plant with similar leaves as the mimosa, I do not know its proper name, false acacia is also similar, apart from the deadly spikes it has all over its branches, not a thing you want in your garden as it also suckers everywhere.
My wattle will not flower until later.
Oh and leave the Bug. Err fly alone.