Few verses are as instantly recognisable as "Roses are red / Violets are blue," and country_guy14's poem begins by quoting that formula and then picking a quarrel with it. The complaint is small and oddly reasonable: violets aren't blue, they're violet. Everything else grows from that act of pedantry. The central idea is that rhyme can pull a statement away from the truth, and that we often say things because they sound right rather than because they are right.
The construction shows this well. Most of the poem runs in a ballad-like pattern where the second and fourth lines of each quatrain rhyme: "blue" with "true," "too" with "blue," "green" with "mean." The first two stanzas are dominated by a single "oo" sound. Blue, true, too and blue again chime so insistently that the poem seems stuck inside the very trap it describes. There is also an irony in the rhyme word "true." The poem uses the blue/true pairing to announce that the old rhyme isn't true, so it needs the rhyme to complain about the rhyme. The repetition does similar work. "Roses are red" returns almost unchanged, but the second time the poem pairs it with "apples are too," a plain, correct fact that makes the false "blue" look even odder. "Violets are violet" is a tautology, and the deliberately flat, obvious phrasing is part of the joke. The poem proves its point by stating the dullest possible truth.
In the second half the examples widen from flowers to language in general. "An orange is orange" is a case where the word and the colour agree, and the next line breaks the pattern: "but Greenland's not green." Then come "pinkies," whose name has no obvious link to the colour pink. The examples are a little muddled, since the first doesn't contradict anything, and that gives the poem a thinking-aloud quality, as if the speaker is discovering the problem line by line. The rhythm helps. Lines like "An orange is orange / but Greenland's not green" have a bouncing, galloping beat, close to a nursery rhyme, which keeps the tone light even as the question gets bigger. "What does it mean?" works on two levels, as a shrug at the confusing colour names and as a real question about how words attach themselves to things.
The ending changes the poem's shape. Up to here the lines are short and tidy, but the last two stretch out: "To say something's blue when it isn't, defiles it." The verb "defiles" is absurdly grand for a quarrel about flower colours, and the mock-solemn tone is funny. The next line deflates it at once: "But oh, what the heck, it's hard to rhyme 'violet'." The casual "oh, what the heck" is the voice of someone giving up gracefully. The line also ends on the word "violet" itself, which has nothing to rhyme with. At most "defiles it" offers a faint echo of its unstressed ending. The poem that accused rhyme of bending the truth finishes by admitting that rhyme is the real reason for the bending. The quotation marks around "violet" matter too, because they turn the flower into a word, which is exactly what the poem has been circling: the gap between a name and the thing it names.
The poem is slight, but it does something worth noticing. It takes a phrase so familiar that nobody checks it and tests it against the evidence. In doing so it shows that poetic form isn't neutral, since the need for a rhyme can quietly decide what a poem claims. It is also a good example of answering a tradition rather than repeating it, and it is generous in doing so. It doesn't sneer at the old verse. It simply points out the flaw, laughs at its own pedantry, and concedes that the original writer had a hard job. A good exercise for readers is to try the same trick on another well-worn saying and see where the rhyme has been doing the thinking.