I wouldn't recommend you eat it, if you don't know for sure.

This website would suggest that it is,
However I think it would warrant further investigation under the name ( Mi Meng Hua )

http://www.buddleia.net/medicinal-buddleia

bfb are edible, tho most parts you wouldn't want to eat and it contains hardly any nutritional value for humans. However, the flowers are beautiful and many varieties sweet smelling, the flowers are edible and their sweet nectar attracts butterflies so I would imagine you could make jelly. The Chinese eat the blossoms all the time in a sticky rice dish where the blooms are mixed in to dye the rice that color. Pretty cool huh? I'll have to think of the name of that stuff. Roses would have much more health benefits and nutrition but for taste you could try. bite off a flower and see what u think.

the yellow sticky rice dish dyed w butterfly Bush blooms is called "hao Lang"