The poem begins with a happy scene: someone invites a companion to look at a plant they once sowed together, now heavy with fruit, some sour and some sweet. The speaker stresses how much it endured, through burning summers, harsh monsoons and freezing winters, so the harvest feels earned.
Then the poem turns on a quiet "But." The speaker has also planted something, a plant of hope, and nothing has come of it. The tone shifts from celebration to weary uncertainty. The speaker doesn't know how long the plant must "burn" or how many nights of pain are still to come. The word "penance" suggests that waiting and suffering are being treated like a price paid for a reward.
The ending is the bleakest part. The speaker wonders whether the reward may never come, and whether the seed was wrong from the start: acacia bushes, or a "moldy hope." The mood is tired, doubtful and quietly sad, with the fear that effort alone doesn't guarantee a result.