So THAT’S what I was doing wrong. Keeping Them Intact is the key.
I say this because, as a kid, I used to do the same thing - Fill balloons with water and add food coloring. My mistake was climbing on the roof of the house and throwing them on the driveway, hoping to cause splatter art on nearby snowdrifts. I guess it diffused the water / food coloring enough that it just made vague stains on the snow, instead of brilliant blotches of color. Shoulda used tempura paints instead of food coloring, I suppose.
