Derek Walcott's "The Almond Trees" seems to have no rhyme scheme if by "scheme" we mean a visible pattern. At most, one sees occasional lines, even stanzas, rhyming. The rhymes disappear only to appear again: sometimes in a flash, at other times distinctly.
Walcott structures the poem with thirteen stanzas (including one of just one line). Some of them contain rhyme, while others do not. However, analyzing the poem, one may discover some revealing features in both the structure of the poem and its unique use of rhyme.
In the very first stanza, the second and the fifth lines rhyme lightly:
There's nothing here
cold churning ocean, the Atlantic,
no visible history
"Early" and "history" share a final vowel sound, but the two words' differing meters soften the effect of the end rhyme. The other four lines in the poem could almost have belonged to prose. However, "early" and "no visible history," together with the short phrases in between, begin to introduce a poetic environment.
The second stanza does not rhyme at all, but the third has the same sort of near rhyme as the first. "Fisherman" in the first line recalls another faint rhyme, "amaze the sun." This time, Walcott enhances the poetic quality by introducing a telling image of an old man with his dog, playfully retrieving a spinning stick. "No visible history" reappears twice in three stanzas. The stanza also contains the line "Their lengthened shapes amaze the sun": "lengthened" because the sun is setting, and with the setting sun, "no visible history" slowly becomes history, the history of what happened to this Caribbean island when the British ruled here. The sun has seen it all, the ruin and its twisted shape, and is amazed.
The fourth stanza is the first one whose lines contain perfect rhyme. The fifth stanza contains perfect rhyme as well as mythological references: the women who come to the beach in the evening are called "daphne[s]." The reference is to the Greek myth about the nymph Daphne, who was pursued by Apollo but saved herself by turning into a laurel tree. Just like the original Greek mythical character, these women, too, will have their laurels and groves of trees, except that these groves are the sea-almond trees.
brown daphnes, laurels, they'll all have
like their originals, their sacred grove,
of twisted, coppery, sea-almond trees.
The ninth stanza, which appears a little beyond the middle of the poem, is fully rhymed:
Welded in one flame,
huddled naked, stripped of their name,
for Greek or Roman tags, they were lashed
raw by wind, washed
out with salt and fire-dried,
bitterly nourished where their branches died
The poet has just finished describing the women who come to the beach, who, by a twist of colonial fate, echo Greek mythology. In this stanza, he describes the ravages the colonial conquerors heaped upon the island. He does it through rhyme, as if recalling the epic stories of the Greek invasion of Troy. This eighth stanza can be considered the climax because what follows after is a slow winding down, the calm after the storm. There is even hope in the end.
Perhaps Derek Walcott employed occasional near rhymes, with one big stanza full of true rhyme, to create a rhythmic sense of the sea breeze on the island. It comes and goes, occasionally fluttering the trees, then blows in gusts to drive everything in front of it. The poem, with its particular rhyming strategy, may be conveying the way people often remember their ancestors' conquered land. Its thirteen-stanza structure sequentially takes the reader from a seemingly innocent description of a beach with almond trees to a devastating colonial history.