What kind of fertilization does butterfly bush need?
Thanks for contacting us. 'Pink Delight' butterfly bush (Buddleja davidii 'Pink Delight') is native to China but has naturalized in several western US states where it reportedly can be invasive. Since you did not indicate your location, I would caution you to be careful that it does not become a problem in your area.
Fertilization is not generally needed provided the soil is healthy with a reasonable level of organic matter (generally 3-5%). A general purpose fertilizer can be used in early spring before the new growth gets started. Be sure to use it according to the labelling instructions. The seaweed foliar spray is not needed, but it would probably not be harmful either.