Plants: K
- Kale Brassica oleracea var. sabellica Brassica
- Kalm's St. John's Wort Hypericum kalmianum Wildflower
- Kamchatka Stonecrop Sedum kamtschaticum Creeping perennial
- Kangaroo Paw Anigozanthos flavidus Wildflower
- Kentucky Bluegrass Poa pratensis Creeping perennial
- Kentucky Wisteria Wisteria macrostachya Flowering shrub
- Key Lime Citrus x aurantiifolia Tree fruit
- King Protea Protea cynaroides Flowering shrub
- King's Mantle Thunbergia erecta Flowering shrub
- King's Spear Asphodeline lutea Garden perennial
- Kinnikinnick Arctostaphylos uva-ursi Creeping perennial
- Kiss-Me-Over-the-Garden-Gate Polygonum orientale Garden perennial
- Kiwi Actinidia deliciosa Berry
- Kobus Magnolia Magnolia kobus Flowering tree
- Kohlrabi Brassica oleracea var. gongylodes Brassica
- Korean Azalea Rhododendron yedoense Flowering shrub
- Korean Bellflower Campanula takesimana Garden perennial
- Korean Mint Agastache rugosa Herb
- Korean Rhododendron Rhododendron mucronulatum Flowering shrub
- Korean Velvet Grass Zoysia matrella var. pacifica Grass
- Koreanspice Viburnum Viburnum carlesii Flowering shrub
- Kousa Dogwood Cornus kousa Flowering tree
- Krauss's Spikemoss Selaginella kraussiana Creeping perennial
- Kumquat Citrus japonica Tree fruit
- Kura Clover Trifolium ambiguum Creeping perennial