Originally Posted by
rando
yeah, they don't grow ON the pavement, but NEXT to the pavement, and if you veer off at all into a patch of dirt/weeds or take a short cut through a vacant lot you can pick them up--- I steered around a couple walking on the sidewalk, went into grass/weeds for about ten feet, and when I looked down again my tire was covered in goatheads.
They don't sprout
on pavement but they will certainly spread across pavement, sidewalks and other hard surfaces. Considering that the plants don't do well in competition with other plants...they prefer barren disturbed soils...the hard surfaces may be ideal for them. I've seen the plants up to 8 feet in diameter with large amounts across hard surfaces.
Of course when people run off into the weeds and collect them
, they also spread them all over the path where other cyclists pick them up
