In The Garden: Shrub With Purple Flowers In Colombian Garden

This woody plant growing to about two meters high spreads like a weed. I'm sure it was planted by the former owners. It is decorative but dies off fairly quickly. Can anyone tell me what it is?

 

Melastomaecae, probably a Tibouchina.

 

Thank you that certainly looks to be it. I wonder id it might be T.semidecandra native to Brazil.

 

Tibouchina heteromalla(grandifolia)?
http://www.garden.bsewall.com/images/flowers/tibouchina.html

 

That certaunly looks like my plant. Thanks again.