Yes! Watermelon is so sweet and sugary that you can skip the sugar completely, but you'll get a better texture and flavor if you add a little sweetener. When foods are cold, we can't taste nearly as much sweetness, which is why most ice creams and popsicles have lots of extra sugar. Plus, honey is a type of inverted sugar, which will help prevent the popsicles from being overly icy. You only need a little bit to make a big difference!