Clwt is a welsh word for a dishcloth. Even before she became the National Poet of Wales, Clarke worked in both Welsh and English throughout her career. The significance of the word in this poem is that it adds a personal detail to remind the reader that, while many of the poem's details are broad, there is a specific connection to Wales throughout. Furthermore, it might subvert the expectations of non-welsh speakers as they might assume that the word rhymes with "knit" on the preceding line, but it does not. Clarke could be playfully implying that, when it comes to both language and nature, the more a person knows, the better their understanding will be.