Anacharis is another one that produces those chemicals. I have at least 4 feet of hornwort (and a little bit of anacharis too) in a plant grow-out tank basically covered in algae at the moment. I wouldn't depend on those chemicals... having the right balance in the tank is vastly more effective.
i have swords in a couple of my tanks and have never had a problem with algae. I have alittle bit with my tank that doesn't have any plants at all. I scrub it off b4 water changes.