Bring Me A Shrubbery
Next time you visit grandma and grandpa you might want advise them not to buy "pretty plants" from a dude selling them out of the trunk of his car. If it's too late and they have bought plants from anyone other than a reputable nursery, you might want to check their garden and make sure they are not accidentally growing pot.
It seems an elderly British couple purchased a shrubbery from a boot sale in London (from what I can tell a boot sale is like a flea market), took the plant home and planted it in their garden.
After police discovered the plant they questioned the couple and determined they indeed did not know it was cannabis. After discovering the plant, police posted a picture of it on Twitter and said, "Elderly couple bought shrub at boot sale, adding it was the biggest cannabis plant we have ever seen."
Police seized the plant and say they will handle disposing of it, and that no charges will be filed.