Yeats’s speaker looks back on youth as a time of “lying days,” when he showed off bright leaves and flowers to the sun. Those many surfaces felt alive, but they were not the whole story. Underneath them all, he says, there is a single root—one lasting truth. The poem moves from that observation to a quiet, almost sideways hope: now that he is older and his outward show is fading, he may finally “wither into the truth.” The word “wither” is deliberately unglamorous. It suggests loss, dryness, decline. But in this poem that loss is also a kind of focusing: fewer distractions, fewer false selves, perhaps a clearer view of what was always underneath. The mood is meditative and autumnal—not exactly sad, but full of the seriousness that comes when someone measures what youth cost and what age might return.
The Coming of Wisdom with Time — Summary
Though leaves are many, the root is one; Through all the lying days of my youth I swayed my leaves and flowers in the sun; Now I may wither into the truth.