Ice plant is rampant here. People in San Francisco use it for erosion control.
The hideous stuff in my garden is Arum Italicum, and weeds are far preferable to me because they can at least be pulled. I'll take some pictures of the stuff in my garden and you'll see that it actually can choke out little roses. It gets taller than some roses and blocks all of the light and moisture, so I have to rip off the tops of it to let the roses breathe. It grows back constantly, however.
I can't dig it out because every time I dig up a large bulb, lots of little bulbs fall off the big one and embed themselves in the ground. If I wanted to get every single bulb out, I'd have to dig out every plant in my garden and replace the soil, and even then it would soon come back, spreading over here from the neighbors' gardens.
http://en.wikipedia.org/wiki/A...
Cinda, the stuff in my neighborhood did start out as a houseplant. One of my neighbors was trying to see whether her Arum houseplant would grow outside, and now it has spread to about 30 or 40 gardens in the neighborhood.