I am curious to try champaca flower essence after reading this:

“Those who are familiar with the Nag Champa incense may find champaca scent to be somewhat similar. The reason being that Nag Champa incense incorporates halmaddi, a grey, semi-liquid resin taken from the Alianthus tree, which smells very similar to champaca flower.”

— from “Champaca Flowers vs. Nag Champa Incense” by Ayala Sender, from her SmellyBlog.