Posted: 25/06/2017 at 18:21
the internet is full of rubbish, anyone can post anything.
Any plant species, where it's happy, will seed, sometimes seed a lot. Gardening is about thinning these seedlings out. It's called weeding, it's what gardeners do.. Sweet Rocket doesn't kill plants but massed seedlings might swamp something less strong. All down to the gardener.