Common names: K
- Kaempfer azalea
- Kahili ginger
- kaki persimmon
- kale
- Kamchatka stonecrop
- kangaroo apple
- kangaroo paw
- Kansu crab apple
- kapok
- kapur
- kapur tree
- karo
- katsura tree
- Kauai red rosemallow
- Kaufmanniana tulip
- Kelsey's locust
- kenaf
- Kentucky coffeetree
- Kentucky wisteria
- Kentucky yellow wood
- Kew broom
- Kew primrose
- king protea
- kiwi
- knapweed
- knife leaf wattle
- knight's polypody
- knotgrass
- knotted cranesbill
- knotweed
- Kobushi magnolia
- kohlrabi
- konjac
- Korean barberry
- Korean bee tree
- Korean bellflower
- Korean birch
- Korean boxwood
- Korean clematis
- Korean date
- Korean fir
- Korean forsythia
- Korean lilac
- Korean mountain ash
- Korean spice viburnum
- Korean whitebeam
- krachai
- kumquat
- kurrat