'Nettles' is an account from the perspective of a father of how his son fell into a nettle bed. The poet personifies the nettles to appear like an army, showing how relentless nature can be. This contrasts with traditional views of nature as good and pure.
In the second line, Scannell highlights the irony of the collective noun "bed" which is used to describe a cluster of nettles. Highlighting the discomfort they cause, he goes on to use the metaphor "spears" to compare them with weapons, items which are traditionally used to deliberately cause harm. This introduces the personification of nature, with the idea of intentional harm continuing throughout the poem.
Other examples of personification of the nettles include "That regiment of spite", "that fierce parade", "the fallen dead" and "tall recruits". What unites all of these images is the military metaphors created, with the nettles being likened to large groups of men intentionally using violence. The collective noun "regiment" emphasises the power created by the sheer numbers of nettles, which are presented as a formidable force. Scannell uses a tone of respect and remembrance with "the fallen dead", thus showing how he recognises that nature simply follows... well, it's nature! Plants and animals are conditioned to survive, and Scannell clearly respects this survival instinct.
Further personification is used to describe "the busy sun and rain", which are seen as controlling forces in the nettles' battle against the speaker. Here, Scannell is portraying not only the nettles, but the whole of nature being at war with humans, especially with him and his son.
Ultimately, Scannell realises through this incident that he cannot protect his son's innocence forever, and that the whole world is a damaging, hurtful place, stating "my son would often feel sharp wounds again". Here, he is referring to both the physical and emotional pain which leads to the loss of innocence. His innocence is emphasised through the image of his "tender skin", which has not yet become hardened by age and experience. Furthermore, the "watery grin" suggests his tearfulness, and the lack of force in his smile, having not yet matured enough to do anything but show how he is truly feeling.
What do you think about the structure of the poem?