Japanese Knotweed [Polygonum cuspidatum]
Japanese Larch [Larix kaempferi]
Jaragua [Hyparrhenia rufa]
Jatropha gossypiifolia [Bellyache Bush]
Johnsongrass [Sorghum halapense]
Joyweed, West Indian [Alternanthera crucis]
Juglans nigra [Black Walnut]