| Cultivar Name | Plant Size | Origin | Flower Color | Season | Source | Registered |
| 'J.B. Patel' | Medium | Hybrid | Near-White | June into July | Kwick, Charles | .2018 |
| 'Jack Robbins' | Large | Unknown | - | - | Minks, Eldren | --NR-- |
| 'Jack's Gene' | Medium | Hybrid | Med-Lavender | July into August | Goodenough, Rick & Gilligan, Madelon | .2015 .2018 |
| 'Jade Beauty' | Medium | TC Sport | Pale-Lavender | July | Zilis, Mark | .1988 |
| 'Jade Cascade' | Giant | Unknown | Pale-Lavender | July | Heims, Dan & Walek, Kevin | .2009 |
| 'Jade Elegance' | Large | Unknown | Near-White | June into July | Unknown | --NR-- |
| 'Jade Moon' | Large | Sport | Pale-Lavender | July into August | Unknown | --NR-- |
| 'Jade Patriot' | Large | Sport | Med-Lavender | July into August | Unknown | --NR-- |
| 'Jade Point' | Large | Hybrid | Near-White | June into July | Simpers, Lucille | .1980 |
| 'Jade Scepter' | Medium | TC Sport | Deep-Purple | July | Zilis, Mark | .1988 |
| 'Jade Tiara' | Medium | Sport | Light-Purple | July | Walters Gardens | --NR-- |
| 'Jaded Geisha' | Medium | Sport | Light-Purple | August to September | Hawes, James | --NR-- |
| 'Jalapeno' | Medium | Unknown | - | - | Unknown | --NR-- |
| 'Jamboree' | Small | Unknown | - | - | Malloy, Alex | --NR-- |
| 'James A. Garfield' | Medium | Hybrid | Pale-Lavender | August to October | Sugita, Hajime & Ruh, Peter | .2005 |
| 'James Buchanan' | Small | Unknown | Pale-Lavender | June into July | Sugita, Hajime & Ruh, Peter | .2005 |
| 'James Knox Polk' | Giant | Unknown | - | - | Ruh, Peter & Ruh, Jean | .2010 |
| 'James Madison' | Medium | Hybrid | Light-Purple | August to October | Sugita, Hajime & Ruh, Peter | .2005 |
| 'James River' | Medium | Hybrid | Med-Lavender | July into August | Beilstein, Doug & Malloy, Alex | .2005 |
| 'Jane Doe' | Large | Sport | Pure-White | July into August | Nyikos, Frank | .2017 |
| 'Janet Green' | Small | Unknown | - | - | Unknown | --NR-- |
| 'Janet's Green Sox' | Medium | TC Sport | Pale-Lavender | July | Wade, Van | --NR-- |
| 'Jan's Gem' | Medium | Unknown | - | - | Wade, Van | --NR-- |
| 'Japanboy' | Small | Unknown | - | - | Kohlein, Fritz | --NR-- |
| 'Japangirl' | Miniature | Hybrid | - | - | Unknown | --NR-- |
| 'Jarett H Park' | Large | Hybrid | Near-White | July into August | Chamberlain, Steve | .2003 |
| 'Java' | Medium | Sport | Pale-Lavender | June | Zilis, Mark | .2003 |
| 'Jaws' | Small | Unknown | Med-Lavender | July | Scheer, Alttara | --NR-- |
| 'Jay P. Warren' | Giant | Hybrid | Near-White | July | Chamberlain, Steve | .2004 |
| 'Jaz' | Small | Hybrid | - | - | Johnson, Greg | .2004 |
| 'Jeanne Normandin' | Large | Unknown | Med-Lavender | July | Bastille, Jocelyne | --NR-- |
| 'Jennifer's Green Eyes' | Small | Sport | Pale-Lavender | July | Unknown | --NR-- |
| 'Jerry's Jest' | Small | Hybrid | - | July into August | Schulz, Ed | .2010 |
| 'Jessica Alba' | Medium | Sport | Med-Lavender | August to September | Van den Top, Jan | --NR-- |
| 'Jim and Ellie' | Large | Unknown | - | - | Unknown | --NR-- |
| 'Jimmy' | Small | Hybrid | - | - | Wade, Van | --NR-- |
| 'Jimmy MacBlack' | Medium | Sport | Pure-White | July into August | McBurney, Jim & McBurney, Lois & Anderson, Marlys | .2011 |
| 'Jingle Bells' | Medium | Hybrid | Deep-Purple | August to October | Grapes, Vivian & The American Hosta Society | .1986 |
| 'Jipson Place Black Hole' | Giant | Sport | Near-White | June into July | Butler, Dick & Street, Dr Jamie | .2017 |
| 'JoBob' | Large | Unknown | Med-Lavender | June into July | Gilligan, Madelon | --NR-- |
| 'John Arva' | Large | Hybrid | Light-Purple | July into August | Zolock, Steve & Zolock, Sarah | .2007 |
| 'John D. Barnot' | Large | Unknown | Med-Lavender | July into August | Zolock, Steve & Zolock, Sarah | .2008 |
| 'John Diamond' | Medium | Unknown | - | June into August | Zolock, Steve & Zolock, Sarah | .2009 |
| 'John Henry' | Medium | Hybrid | Light-Purple | August | Livingston, Ron | --NR-- |
| 'John James' | Large | Unknown | Pure-White | July into August | Zolock, Steve & Zolock, Sarah | .2007 |
| 'John Jay' | Medium | Unknown | - | - | Malloy, Alex | --NR-- |
| 'John Metzgar' | Medium | Hybrid | Light-Purple | July | Zolock, Steve & Zolock, Sarah | .2004 |
| 'John Wargo' | Medium | Hybrid | Light-Purple | July | Weissenberger, Henry | .1986 |
| 'Johnnie Walker Red' | - | Unknown | - | - | Van Ostrand, John | --NR-- |
| 'Jolly Green Dwarf' | Small | Hybrid | Deep-Purple | June into July | Avent, Tony | .2006 |
| 'Jolly Green Giant' | Giant | Unknown | Pale-Lavender | June into July | Armstrong, Maxine & The American Hosta Society | .1986 |
| 'Jon's Gem' | Medium | Unknown | - | July into August | Hatfield, Handy | .2009 |
| 'Joseph' | Large | Sport | Light-Purple | July into August | Kuk, Bob | .1990 |
| 'Joshu Iwa' | Small | Hybrid | - | - | Sugita, Hajime | --NR-- |
| 'Judith' | Miniature | Unknown | Light-Purple | July into August | Gasparino, Judith | .2017 |
| 'Judy Reese' | Medium | Unknown | - | - | Unknown | --NR-- |
| 'Judy Rocco' | Medium | Hybrid | Pale-Lavender | September | Johnson, Greg | .2004 |
| 'Julien and Nathalie' | Small | Unknown | - | - | Bastille, Jocelyne | --NR-- |
| 'June Bug' | Medium | Sport | Med-Lavender | July | Lydell, Ransom | .1999 |
| 'Just Elegant' | Large | Unknown | - | - | Serafin, Viktoria | --NR-- |
| 'Just Green' | Small | Unknown | - | - | Unknown | --NR-- |
| 'Just So Green' | Small | Sport | Pale-Lavender | June into July | Wade, Van | --NR-- |
| 'Justin' | Medium | Unknown | - | - | Malloy, Alex | --NR-- |
| 'Justin Tyme' | Giant | Hybrid | Near-White | June into July | Hicks, Gerry | .2017 |
| 'Jyunpakuka-akebono' | Large | Sport | Pure-White | July into August | Unknown | --NR-- |
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