aromatic-shrub Australian Australian-native-flora blooms blossom bracts bush calyces calyx color colored colors colour coloured colours display displayed evergreen flora flower flowering flowers foliage full-bloom hardy Lamiaceae large-flowers magnificent-mint-bush magnificent-prostanthera native perennial prostanthera prostanthera-magnifica purple purplish-red-calyces sepals spreading-shrub two-tone-purple Western-Australian-native-flora wild wildflower wildflowers