- Jack pine
- Jack-in-the-Pulpit
- Jacob's ladder
- Japanese barberry
- Japanese climbing fern
- Japanese creeper
- Japanese honeysuckle
- Japanese Hops
- Japanese knotweed
- Japanese pachysandra
- Japanese stiltgrass
- Jersey Cudweed
- Jerusalem artichoke
- Jerusalem cherry
- Jetbead
- Jewels of Opar
- Jimsonweed
- Johnson grass
- Jointed rush
- Jojoba
- Juniper haircap moss