Q.Butterfly Bush Drooping
New plantings this year

Certified GKH Gardening Expert
My first thought is overwatering. Is that a possibility? Make sure the soil is well draining. If it isn't, add some compost or peat moss to help it. Neem oil sprayed on the top and underside of leaves will help if there is a fungal or insect issue like spider mites. These articles should help:
https://www.gardeningknowhow.com/ornamental/shrubs/butterfly-bush/problems-with-butterfly-bush.htm
https://www.gardeningknowhow.com/ornamental/shrubs/butterfly-bush/butterfly-bush-diseases.htm
https://www.gardeningknowhow.com/ornamental/shrubs/butterfly-bush/brown-leaf-spots-on-buddleia.htm
https://www.gardeningknowhow.com/ornamental/shrubs/butterfly-bush/butterfly-bush-care.htm