The only problem with planting out nasturtiums in public here, is that we have a prevalent weed we call "pennywort" with leaves that look identical to nasturtiums (but are tougher and stringier, and taste terrible instead of delicious). The only time you can actually tell the difference between the two plants is when they flower - pennywort have quite a different flower. Most people, me included, are running a mighty campaign against pennywort, so I don't like its chances of being left unmolested around here ...