Those flowers in the park that the bees love are melliferous, because the nectar they produce allows bees to make honey.
Melliferous describes things that produce honey or provide the means to produce it. Honeybees, for example, are melliferous creatures, and flowers that produce nectar are melliferous, too, as they provide the raw material that bees need to make honey. Mel is a Latin word meaning "honey," and it has influenced many languages; for instance, the words for honey in Welsh (mêl), Irish (mil), and French (miel) all share this root. Another English word derived from this root is mellifluous, which describes a sound that is sweet and smooth like flowing honey.