| Cultivar Name | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
| 'Kaboom' | Large | Med-Green | | | Hybrid | Light-Purple | | White, Jeff | --NR-- |
| 'Kaiapoi' | Giant | Blue/Green | - | - | Hybrid | Near-White | June into July | Gilligan, Madelon | .2012 |
| 'Katsuragawa Beni' | Medium | Med-Green | - | - | Unknown | Light-Purple | August to October | Masoka, Hiroshi | --NR-- |
| 'Kayla Marie' | Medium | Med-Green | Streaked | White | Unknown | - | June into July | Boak, Tim | .2012 |
| 'Kempen Golf Sticks' | Large | Med-Green | - | - | Unknown | - | - | Butaye, Patrick | --NR-- |
| 'Kempen Light Goalkeeper' | Large | Light-Green | | | Unknown | | | Butaye, Patrick | --NR-- |
| 'Kempen Manta Ray' | Small | Blue/Green | | | Unknown | | | Butaye, Patrick | --NR-- |
| 'Kempen Red Twist' | Large | Med-Green | Streaked | White | Hybrid | Pale-Lavender | July into August | Butaye, Patrick | .2014 |
| 'Kempen Rhubarb Taste' | Large | Med-Green | - | - | Unknown | - | - | Butaye, Patrick | --NR-- |
| 'Kempen Saw Blade' | Medium | Med-Green | Streaked | White | Hybrid | - | July | Butaye, Patrick | --NR-- |
| 'Kempen Waving Shadow' | Medium | Light-Green | - | - | Hybrid | - | - | Butaye, Patrick | --NR-- |
| 'Kichou' | Small | Med-Green | Streaked | Yellow | Unknown | - | - | Tanaka, Katsuyoshi | --NR-- |
| 'Kifukurin Ki Hachijo' (Japan) | Small | Med-Green | Marginal | Yellow | Sport | Med-Lavender | September | Unknown | --NR-- |
| 'Kill Me Softly' | Small | Dark-Green | - | - | Unknown | - | - | Scheer, Alttara | --NR-- |
| 'Kim She' | Small | Med-Green | Marginal | Yellow | Hybrid | - | August | Avent, Tony | --NR-- |
| 'Kinba' | Large | Med-Green | - | - | Hybrid | Light-Purple | - | Watanabe, Kenji | --NR-- |
| 'King Cobra' | Medium | Light-Green | - | - | Hybrid | Pale-Lavender | June into July | Scheer, Alttara & Gilligan, Madelon | .2015 |
| 'King Crimson' | Medium | Med-Green | - | - | Unknown | - | - | Unknown | --NR-- |
| 'Kinugawa Nishiki Iwa' | Small | Med-Green | Medial | Yellow | Sport | Light-Purple | August to September | Suzuki, Kichigoro | --NR-- |
| 'Kiwi Red Heron' | Large | Blue/Green | - | - | Unknown | - | - | Sligh, Barry | --NR-- |
| 'Kofuki Iwa Giboshi' | Medium | Light-Green | - | - | Unknown | Light-Purple | September | Maekawa, Dr Fumio | --NR-- |
| 'Kogarashi Nakafu' | Miniature | Med-Green | Medial | Yellow | Sport | Med-Lavender | September | Unknown | --NR-- |
| 'Kosasa Nishiki Iwa' | Small | Med-Green | Streaked | Yellow | Unknown | Pale-Lavender | - | Kosasa | --NR-- |
| 'Kozu Nishiki' | Medium | Med-Green | - | - | Sport | Med-Lavender | September | Unknown | --NR-- |
| 'Kufikiu Iwa' | Medium | Med-Green | | | Unknown | | | Unknown | --NR-- |
|