Richard II: Metaphor Analysis

Imagery
Richard II is rich in poetic imagery. Richard, the king of England, is frequently compared to the sun, as the "king" of the planets. This was a commonplace of the Renaissance, and was used to convey the orderliness of the "great chain of being." The comparison occurs in Act 3, scene 3, for example:
See, see, King Richard doth himself appear,
As doth the blushing discontented sun
From out the fiery portal of the East
When he perceives the envious clouds are bent
To dim his glory and to stain the track
Of his bright passage to the occident.
Richard likens himself to the sun in Act 2, scene 2, lines 36-53. When the sun rises it exposes thieves and wrongdoers who work only by night. So when Richard appears, Bolingbroke's wrongdoing will also appear.
There are also many image clusters that help to reinforce the themes of the play. For example, there are repeated images of earth, land, soil, and ground. These evoke nationhood, the land of England, as well as England's traditions and civilization; they also suggest the life of nature, showing how the two are linked. One cannot offend the one without causing rupture in the other. Images of sickness and infection reinforce this idea.
Similarly, there are birth and womb images ("this teeming womb of royal kings" in Gaunt's speech about England, for example), as well as images of blood. These are all linked to matters of human inheritance (of property, social status) through generations. The linking of the natural and the social orders conveys the idea that the offenses that occur in the play (as well as the murder of Gloucester that took place before it begins) are violations of nature as well as human laws.
Allegory
The garden scene (Act 4, scene 4) is a political allegory. The gardener compares the garden to the kingdom and explains that the rules for tending the garden should be applied to tending the kingdom. The good ruler is like a good gardener. This allegory lends weight to the imagery found in the play generally, of the correspondence between the natural and the human world.
Another level of meaning is supplied when the queen refers to the gardener as "old Adam's likeness." This allusion to the Book of Genesis suggests that England is like the garden of Eden that has been spoiled by the transgressions of the king. It puts in mind the famous speech by Gaunt in Act 2 scene 1, in which he refers to England as "This other Eden, demi-paradise." The dying Gaunt is the representative of the old order in England that is dying, due to Richard's folly. The ruin of the kingdom is like another fall of man.