Anger usually needs a target, and the target here is an odd one: trees. The speaker "glares upon trees and leaves", and the reason arrives in a single run-on sentence. Trees lose their leaves and "simply" grow them back, while the speaker's heart "fell for you" and "smashed to pieces." The central idea is the unfairness of that contrast. Nature seems to recover without effort, but a person who has been hurt in love has no such guarantee. The glare is really envy, and under the envy is grief.
The poem hangs on the word "fall." In the first half it describes what leaves do, and in the second it describes what the heart does, and the two meanings are quite different. "Fall" for the leaves is a seasonal event, even a gentle one. "Fell for you" is the everyday phrase for falling in love, and the poem then lets the physical sense of the word take over, so that falling ends in a crash. The speaker has fallen twice over, once into love and once to the ground. Because the same verb covers both, the heartbreak feels like the natural result of the love, as if the break was built into the fall from the start.
The word choices tilt the comparison. "Glare upon" is slightly formal and slightly hostile, as if the speaker were passing judgment on the trees. "Simply" carries most of the bitterness: for the trees, falling and regrowing is easy, and the speaker has clearly found nothing easy. "Grow back again" is mildly redundant, since "back" and "again" say nearly the same thing, but the doubling suggests a cycle that repeats and repeats. Then comes the shift in imagery. The trees belong to a living, organic world of growth, while the heart "smashed to pieces" behaves like glass or porcelain. Living things regrow, but broken objects have to be mended by someone, and the speaker offers no sign that anyone is doing it.
The form is as plain as the feeling. There is no rhyme and no regular meter, and the poem reads like a spoken thought, almost a confession. It is one sentence, hinged on the word "but." The first half rolls along in a long, even clause about trees, and the second half drops into heavier stresses: "my heart fell for you and it smashed." Even the slightly loose phrasing of "and it smashed" sounds like someone speaking in the moment rather than polishing a line. Sound plays a small part too. The "gl" of "glare" and the "gr" of "grow" link the two halves of the first clause, and "fall" and "fell" echo each other across the "but." "Smashed to pieces" is full of hissing, clipped sounds that seem to break as they are said. The closing ellipsis suggests the speaker has nothing left to say, or that the pieces are still lying where they landed.
There is also a quiet irony in the speaker's logic, though it may be unintended. When leaves fall, they do not come back. The tree grows new ones. Read closely, the comparison is less tidy than the speaker believes, because renewal means replacement, not restoration. Perhaps that is exactly what the speaker cannot yet imagine: a heart that regrows rather than being glued back together. The number in the title, "#7," suggests this is one entry in a series, which fits the sense of a mood caught on the way through something longer. That is an inference from the title, not a known fact.
The poem's significance lies in how much it fits into so little space. It does not explain who "you" is or what went wrong, and it does not need to. A familiar idea, that nature heals and people struggle, becomes personal through a petty, honest, slightly funny image: someone scowling at a tree. That mix of humor and hurt makes the pain believable. Anyone who has resented the world for carrying on as normal after a loss will recognize this speaker. The poem is modest, but the gap between how easily leaves fall and how violently a heart does is exactly what it sets out to show.