To get lucky clovers in your town, your town has to either be full of weeds or you get them by having a lucky clover in your town by odd chance, e.g if you have that one lucky clover growing in town but you play everyday. The reason why I say it has to be full of weeds is because if you time travel a lot, clovers and weeds will spawn. Depending on how far you've time traveled you can get a ton of lucky clovers by plucking clovers some won't always be a lucky clover, but i've found this the easiest method to get several at once since they'll be so many. If you have a cycle town this would work better, because it'd mean you don't have to time travel in your main town if you don't want to time travel. Or you could just buy some on here from a landscaping shop in the tbt marketplace, they sell them for pretty cheap and they aren't all that expensive in tbt.