Hydrangeas and roses, popular garden flowers, can benefit greatly from the addition of coffee grounds. Coffee grounds provide a natural alternative to store-bought fertilizers, and gardening enthusiasts have witnessed positive results in their own gardens. Acid-loving plants like hydrangeas and roses thrive when sprinkled with coffee grounds, as the organic matter improves soil structure, aids water retention, and stimulates microbial activity. The caffeine in coffee grounds acts as a natural stimulant, promoting nutrient absorption and resulting in healthier, more robust plants. While excessive caffeine can inhibit growth, a moderate amount of coffee grounds can work wonders for these plants. To apply coffee grounds, simply sprinkle them around the base of your plants or mix them into the soil. Over time, this can also help increase soil acidity, contributing to the development of blue hydrangeas.