Wutan> Ume or Cattleya are perfect for that. You could even use them in different teams and leave a place for a more offensive SB girl. Promoted Lavender is a little monster or, even better, Scotch Broom/promoted Moonflower. they give 60% ATK for 300% Solar Blast used. With +75% from Dogwood, you can easily start the fight with 155% ATK just with thoses two girls (Scotch Broom/promoted Moonflower also bring +20% ATK) and free damage to everything from 300% Solar Blast.
Actually, SB is very strong but options to build a team with that are too limited and works only with rainbows.

(for me, I guess Dogwood is A tier, close to S tier when used with similar girls. Maybe the only girl deserving a S tier without being broken).