Any of several Australian plants; especially an almost leafless shrub, Apophyllum anomulum (family Capparaceae), with fragrant yellow flowers and shoots that taste like mustard.
Origin
Late 19th century.
Definition of mustard bush in US English:
mustard bush
noun
Australian
Any of several Australian plants; especially an almost leafless shrub, Apophyllum anomulum (family Capparaceae), with fragrant yellow flowers and shoots that taste like mustard.