The first stanza tells us that the nettles tower over the implements, except for the roller handle, as if they want to assert the supremacy of life and hide the fact that even things made from the most obdurate materials are subject to change and will eventually disappear. Yet, it is implied, the nettles grow in spring and will die in due course and what is now hidden will be revealed once again.
The words "cover up" mean the nettles "grow over" but also imply "attempt to conceal".
The stanza also poses the paradox that truth can be revealed through illusion. The illusion here is that life is triumphant, as we know that the implements are lying under the nettles and will be revealed once again when the nettles themselves die - and the illusion will be revealed for what it is also.
The "painting" assonance of the short -u- vowels in "cover", "done", "rusty" and "butt", together with the frequent pauses between the items in the list, convey an impression of exhaustion and reinforces the notion of something that is moribund or very near death.
In the second stanza, the narrator explains why he likes this corner of the farmyard most. He tells us that he likes the dust on the nettles - a reminder of mortality - which is never finally removed although temporarily washed off by the showers that may briefly refresh but otherwise make no difference at all (it is an illusion that they do).
He makes it clear that he has no unnatural liking for death by saying that he also likes the bloom (covering of fine powder, here representing the fullness of life) on flowers. However, the yoking of "bloom" and "dust", and dismissive tone of the word "any", suggests that he knows the bloom will disappear also,...