q: planted cactus arm starting to flower... does this mean it's rooting???

Hi,

I was on holiday recently (6 weeks ago) and found a broken cactus arm 
lying in the pavement so I brought it home.

I planted it, and it's certainly straighted up (it was very bent) and 
now it's flowering! (a single red flower).

Do you think this means it's started to root? I'd love it if it did.

Thanks a lot,

Tom