One thing, planting close gives weeds less of a chance to take over. Second, even when I plant with distance, which I actually do sometimes too, they fill in with years of growth and some multiplication. In order to remember who is who, I have EON mini markers.
The first bed, the actual mixed bed I call Ramona's Inspiration, because she (Ramona, Faraway Flowers) inspired me to create it starting with daylilies, which I had a few of, and several more now, then I filled those daylilies in with lilies, coneflowers and tree peonies, primarily, though there are a few other odds and ends in there. The coneflowers are 'Firebird', 'Pink Poodle' and 'Tomato Soup'....I think, if I recall correctly. Just to stick up for myself, I will tell you that there are at least 20 varieties of daylilies in there, no kidding.