Horticulture
Images of gardening, horticulture, and natural growth appear frequently throughout 1 Henry IV. Most commonly, the imagery provides a figurative way for characters to conceive of the overall "health" of Britain: they compare the state to a garden, with the king as the gardener who tends to his plants. The rebels, by contrast, think of England as a garden invaded by a "thorn" or weed (i.e. King Henry) that will eventually strangle the health of the nation. This imagery is important to the play because it showcases the way different characters perceive the responsibilities and roles of the king.
Stars
Star and sun imagery abounds in the play, usually as a means of describing the king or other powerful figure. This was a common comparison in early modern English art and culture, which tended to portray monarchs as semi-divine beings shrouded in sunlight. At the end of the play, Prince Hal declares that Britain is simply not big enough to accommodate two shining "stars" – him and Hotspur – before defeating Hotspur and placing himself in the position of the "sun." This imagery will be repeated both in 2 Henry IV and Henry V.
Mutilation
Talk of bodily mutilation plays a significant role in the play in two major ways: first, the notion of maiming with regard to warfare suggests not just the destruction of an individual body but also the "body" of England as a whole. That is, in describing the atrocities done to English soldiers on the battlefield, Henry stokes fear that the entire nation is vulnerable to the same mutilation or ruin. Second, bodily mutilation in the form of castration reflects the play's larger theme of gender, specifically the fear of the feminine intruding on the masculine sphere. When news is reported that the English soldiers' bodies were castrated by Welsh women, it dramatizes the masculine paranoia over becoming "soft" or "weak" like their female counterparts.
The Supernatural
There are frequent references to the supernatural throughout the play, usually as a means of accusing characters of shady behavior. Glendower leans into these accusations, attempting to shroud himself in mystery by claiming that he conjured the devil to aid his army in the battle. However, these claims are often met with jests that deflate their severity and render Glendower's "mystery" a farce. Whereas elements of the supernatural have played important roles in other Shakespeare plays (usually tragedies, but some history plays as well), in 1 Henry IV they become somewhat meaningless, with characters instead choosing to focus on the reality of war and governance.
