At one point the farmers tie a bottle to a pear tree and stick a small branch with a blossom inside. They do this so, in a few months, the result will be a full sized pear inside the bottle, much too big to have been put into the bottle in the usual way. One of the farmers uses it to make a bottle of a pear flavored alcoholic drink, with the pear still inside, and the bottle, pear, and drink appear late in the film when the two farmers and Sandrine have a drink together.
The French title, translated as "A Swallow Made a Spring", is a variation of an old saying that "one swallow does not make a spring".