Very poetic. If it comes from a similar style, it is also a means to arouse interest. Metaphorically, "Mulberry flourishes before it falls" in the Book of Songs Feng Wei: When mulberries grow, the leaves flourish. Mulberry leaves are relatively fat, which means that women are young and beautiful. When you say it, you mean when men have strong feelings.
So the literal meaning of this sentence should be: the road to go tomorrow, mulberry and catalpa are sandwiched in the middle, and the leaves are lush.
You have to read the poem below this sentence to know what it is about.