One of my neighbors had a houseplant of it about 25 or 30 years ago and planted it outside. It has now spread to all of the 40 or 50 homes in my neighborhood. It covers the garden from October to March, obscuring all of the shorter plants. It's apparently impossible to kill too. One of my neighbors got rid of it by mowing it for years, but it came back from all of the surrounding gardens, so he finally sold his house to get away from it.
And it doesn't just spread underground. It ends up in my plant containers and my fish ponds and even grows in the little bit of soil that collects in the crook where branches of trees meet the trunk.
