He threatened to knock you out over some dandelion ‘fluff’ - seriously?? What the **** is wrong with some people. **** needs sufffocating, that will help sort his anger issues.
Have you had any friendlier conversations with him previously, maybe he was having an extra bad day (not justifying his threat) Could having a chat with him when he’s not puffing his chest maybe smooth it over? Unlikely I know, as someone who makes such threats over such trivial matters is probably only an empty crisp packet away from flipping out again. But just a suggestion.
Alpha response now, knock his **** in the next time he even looks at you (assuming you’re confident you could) Don’t even speak, just bang. Trail his unconscious body into the garden and take a dump on his chest, extra alpha points if you stuff dandelion fluff in his mouth. Then, in his own blood, write on his windows - ‘talk to me about my garden again bitch’