Where's the Coffee after Zombie Apocalypse?

Every now and then, I get into serious discussions like "Where will we get coffee after Zombie Apocalypse?" 

It's an important question. I live in the US and there are no native coffee plants there. 

So, naturally I’m a bit worried that the coffee will run out fast, and then things would get bad. After all, you are going to have to stay alert in a situation like that.

So I’ve done some research, and it turns out there is a Holly bush that produces caffeine, and was used by Native Americans. It’s called Yaupon. The official name is Ilex Vomitoria if you want to buy it. So you can all relax. There will be coffee after Zombie Apocalypse. Sort of.