Metaphor - describes Malcolm as the rightful heir to the throne- seen as a symbol of good and rightful rule.
Contrastingly Macbeth and his tyrannical rule is seen as a disruption to the natural order + unwanted just as a weed is, thus he needs to be rapathetically cut down.
Emphasizes the contrast between Malcolm's rightful claim to the throne and Macbeth's usurped power.
Metaphor suggests that the actions of Macbeth and his supporters are unnatural and destructive, while Malcolm's rule will be a source of growth and prosperity.
