Compiled from the Note Identification Project Thread:
Petitgrain: smells like neroli, but greener, herbaceous.
Petitgrain : gorgeous scent, close to what I remember when I used to own this EO. Dark orange, wood, citronella, orange peel, smoke
Petitgrain I like this one too. again just a bit of something herbal- almost to help clear your sinus’s side on top with an earthy warm wood
Petitgrain Essential Oil - extremely interesting! Where have I smelled this before? It's like citral a bit, but lighter and more pleasant like limonene. Let's look it up.... Steam distilled from the leaves of citrus trees. Neither of those substances as a main component, but lots of some related substances. Depends strongly on the variety. Very cool. Almost as cool as the Ylang Ylang Oil, but not quite. But I'm definitely going to look for this note in things from now on.
Petitgrain - very strong, greenish citrus. Can't explain too well but it definitely needs diluting! I'm more of a fan of the other citruses methinks.
Petitgrain - I think this is a natural essential oil. Now finally I have smelled all of the products of the bitter orange tree, and I like them all. From the heady orange blossom absolute, so sweet and powerful; to the citrusy and sweet yet transparent and austere neroli essential oil, also from the blossom, but heat distilled; to petitgrain, distilled from the twigs of the tree. Petitgrain is the least sweet--I would call it bittersweet--but it still retains the orange aroma plus a giant dose of oily wood. I would put it into the aromatic wood category along with cedar. It is fresh, clean, volatile smelling, and brings to mind a small part of Guerlain Vol de Nuit.
Like neroli but a bit more sour IMO.