Reminds me of that rainbow tier list that 2ch posted.

Most of the ones we have are D-tier because they're single/double/random-target. Sakura being the exception because her bloomed form gave her the 1.2x increased skill rate passive.

S-rank: Broom, Cherry, Viola (yukata)
A-rank: Sakura, Saffron, Nerine
B-rank: Acacia, Iberis, Epidendrum (swimsuit), Oncidium (bride), Snowdrop, Dendrobium, Euonymus, Serissa, Lycoris (miko), Maple
C-rank: Apricot, Ionocidium, Lagurus, Victoria, Victoria (bride), Katakuri, Cattleya, Christmas Rose, Fritillaria, Garden Peony, Hoya, Hollyhock, Dianthus, Ghost Spurge, Habranthus, Viola, Lycoris, Black Baccara, Pumpkin, Ardisia, Mimosa, Mistletoe, Kerria
D-rank: Anemone, Ume (Mei Plumblossom), Cactus (Cactace), Daisy, Dogwood, Flowering Peach, Helenium, Red Ginger (Alpinia)