We have made appeals for information on Facebook  and Twitter and made several phone calls but have failed to uncover the truth behind the decorations.

Readers have surmised that they could be related to an environmental campaign but Bendigo Sustainability Group knew nothing about them.

Other guesses included mental health awareness and even dog theft.

A reader suggested they could have something to do with protests against the Federal Budget and another said they might be for a funeral party.

A comment on the Addy website suggested they represented the day-to-day challenges of having someone with autism in the family.

Crateman's birthday is another theory.

Another reader said they saw a man tying a balloon to a power pole yesterday at 2.30am.

Apparently there have been balloons around the city since last week.

Let us know if you know more!

EARLIER: Black balloons tied to trees and power poles across Bendigo have got people talking.

The mysterious balloons have been spotted along Napier Street, on Pall Mall, Eaglehawk Road and the McIvor Highway.

Please comment if you know the story behind the balloons.