Will Smith's character walks by a yard filled with beautiful roses and remarks to the woman working there, "Banana peels." He goes on to explain that bananas are great fertilizer, especially for roses.
It's true, he tells her. And it is. Bananas are great sources of potassium and magnesium and break down easily, making the nutrients readily available to the plants. You can use bananas in several ways, whole, chopped or as a liquid. Chop the peels up and toss in a compost pile if you have one. Emulsify peels and overripe bananas in a food processor and pour it around the plants. Toss peels in a bucket of water and let it sit in the sun for a few days; then pour around the base of plants. If you prefer, just toss a peel under the shrubs and let nature take its course.