This is a warm-climate shrub that is native to Asia from Southern China to Pakistan. Clerodendrum wallichii (sometimes called C. nutans or Clerodendrum laevifolium - I am unclear as to the correct name), ht 1-1.5 m, has stunning cascades of pendulous white flowers in autumn and is quite breathtaking when seen in full bloom. It grows well in quite shaded parts of the garden and enjoys a reasonably fertile soil. It suckers gently from the base but I have not found it at all invasive. Cut back in early spring - if done before this, it may die during a cold snap. It can be propagated by cuttings taken in spring and autumn. It needs protection from winter cold. It seems to suffer from no pests or diseases. The Clerodendrum genus belongs to the broader Lamiaceae family of plants and contains several attractive shrubs and climbers that do well in Sydney gardens if protected from frost. Avoid C. bungei, however, as it suckers terribly.
Note that Clerodendrum wallichii has been renamed as Clerodendrum laevifolium.