Rebellious granny, 74, who spray-painted 'WTF' on street signs in a bid to stop council from installing speed bumps pleads guilty in court after causing $10,000 in damage

An elderly grandmother who went on a graffiti vandalism spree over the local council's decision to install speed bumps in her neighbourhood has appeared in court.

Mary Jean Kolusniewski, 74, pleaded guilty to five counts of property damage when she briefly appeared Adelaide Magistrates Court on Wednesday. 

Police accused Kolusniewski of allegedly causing $10,000 worth of damage when she painted 28 road signs with the letters 'WTF!' on Weller Street at Goodwood in the city's inner south over a five week period between July 8 and August 11. 

The defaced street signs were in response to City of Unley Council's recent decision to install speed bumps in the street to deter drivers from speeding.

Mary Jean Kolusniewski vandalised street signs in the Adelaide suburb of Goodwood in response to speed bumps being installed by the local council 

A retired teacher, Kolusniewski was arrested and charged after local residents provided photos of the damaged signs and of her to police.

Weller Street residents told Seven News they supported the installation speed bumps as they made motorists slow down.

Kolusniewski, who lives in a nearby street, is currently banned from visiting Weller Street as part of her bail conditions.

It's understood she will contest the estimated damage bill alleged by police.  

Accompanied by her lawyer, Kolusniewski shielded her face and and refused to comment to waiting media as she left court, NCA Newswire reported.

Nor was she up for a chat when later approached by a Seven News crew outside her home.

'Don't you b****y film me, bugger off,' she tells the reporter.

'Go away or I'll call the police.' 

Kolusniewski will reappear in court in January for sentencing. 

Mary Jean Kolusniewski told a Seven News crew to go away after she was approached outside her home following her court appearance on Wednesday

Kolusniewski told The Messenger in August she wanted to make the signs look better.

She later painted the signs a 'lovely' green colour after her initial work was scrubbed off, insisting it was a 'great improvement' on the signs installed.

She added she wanted to make a public point with the local council and argued her actions were 'activism' rather than graffiti.

'I've been fighting these devils for b****y years,' Kolusniewski told the publication.

'I'm trying to make the point that I've actually improved it.

'I did it to prod them into not doing it again and not muck up the next street.'

Kolusniewski is currently banned from visiting Weller Street as part of her bail conditions