It is used as an adjective meaning high or stoned. I first encountered the term while smoking a joint in Brooklyn with two graffiti artists. These guys were first generation American's with Jamaican parents.
A kind of marijuana, usually from Jamaica, with red hairs on the leaves. Overrated according to some, usually brought back to this country inside hollowed-out candles by tourists, under the impression that it is of exceptionally high quality, by virtue of it's being from Jamaica.
Most kids at this high school talk a lot about weed, while knowing shit about it. They could get a hold of some 6-week-old Jamaican red and think they were smoking some kind herb.