A gift of flowers is answered here with a gift of thoughts. The speaker remembers how her beloved kept bringing blooms "all the summer through / And winter," until the "close room" where she sat no longer seemed to miss "the sun and showers." Now she wants to repay him, but she has no garden to pick from. What she can offer are the thoughts she has pulled, on "warm and cold days," out of her own "heart's ground." The poem is a thank-you note and a love declaration in one, and it works by turning an ordinary courtesy, returning a favour, into a picture of two lives growing into each other.
The garden metaphor is worked out with unusual honesty. Her gift is not a flawless bouquet. The beds and bowers of her heart "Be overgrown with bitter weeds and rue," and they "wait thy weeding." The word "rue" does double duty, naming a plant and also meaning sorrow and regret, so the neglected garden doubles as a confession of old pain. Yet she does not apologise for it. She hands over "eglantine," the wild sweet-briar, and "ivy," a plant that clings and endures, and the exclamation in "Here's ivy!" has the small rush of someone pressing a present into your hands. Her offering is prickly, wild and persistent rather than showy, and that makes it feel true. The phrase "as I used to do / Thy flowers" completes the exchange: she once accepted and cared for his gifts, and now she asks him to do the same for hers.
The form supports this sense of balance. The poem is a sonnet in iambic pentameter, and its rhyme scheme follows the Italian pattern in the first eight lines (ABBA ABBA). Then the sestet does something neat, alternating the old B rhyme with a new one (BCBCBC). The result is that seven of the fourteen lines end in the same "-oo" sound: *through, grew, too, withdrew, rue, do, true*. This long echo gives the poem a steady hum of constancy, and the sound itself seems to carry the idea of faithfulness. The turn also doesn't land neatly. The sentence "Indeed, those beds and bowers / Be overgrown" spills over the end of line 8 into line 9, as if the weeds were creeping past the boundary of the octave. The opening lines run on in the same way. "All the summer through / And winter" refuses to stop at the line break, just as his gifts never stopped coming.
Notice, too, how many commands the speaker gives. "Take back," "take them," "keep them," "Instruct," "tell": she speaks as someone confident enough in love to give gentle orders. In the last two lines the commands become almost a vow. "Instruct thine eyes to keep their colors true" asks him to see her thoughts faithfully and not let them fade or be misread. Then comes the closing line, "And tell thy soul their roots are left in mine." Every word in it is a single syllable, which makes it plain, steady and hard to argue with. The image also holds a small paradox. Cut flowers die, and she wants to make sure these will not "pine," but they are going to him with their roots still in her. She gives herself away without emptying herself, and he carries the blossoms while the living source stays with her. Love here is a connection that continues across the distance of the gift.
The poem is also the last sonnet in Browning's *Sonnets from the Portuguese*, so it closes a whole sequence, and it chooses to end quietly, with a bunch of weedy, fragrant plants. It does not climb to a grand declaration. The ending suggests that love is a continuing exchange, in which giving and receiving, flaw and beauty, his garden and her heart's ground all belong to the same shared soil. That domestic modesty is what makes it memorable: the most intense feeling in the poem is carried by the humblest image, a few plants handed from one person to another.