Leanne's sonnet looks back at a past relationship, a time when "you and I were summer." The speaker pictures the two of them as trees: she is a linden, the other person an oaken, steady presence. The memory is tender but unfinished. Someone asked a question, and the speaker's answer was "lost upon the winds of might-have-been," so we're left guessing what was said, or left unsaid.
The second half widens into a meditation on time. Forever is "a dream lost to the dawn," temples crumble, and roses split stones. Yet the closing lines turn hopeful. Boughs bend, survive the thorns, and keep their scars as "treasured souvenirs." The final line imagines laughing "until the summer, you and I," which suggests that the speaker hopes for a return, or at least a peaceful keeping of the memory.
The mood is wistful and quietly resilient: sad about loss, but unwilling to be bitter about it.