| Hostaname | RG | SZ | Leaf color | P | F | Origin |
| H. 'J. D.'s Luck' J. Orlando 2001 | R | | crw,blgre | | | 'Great Expectations' sport |
| H. 'Jack and Margaret's Keynote' C. Owens/Jeanne M. Kapenga/M. D. 2001 | R | | goy | | | 'Shunko Nishiki' hybrid |
| H. 'Jack Frost' Eldren W. Minks 1983 | R | M | gr,ch,we | | | 'Carol' sport |
| H. 'Jack of Diamonds' Robert P. Savory 1985 | R | M | blgr,ye | | | sieboldiana hybrid |
| H. 'Jackpot' D. & J. Ward 1996 | R | | y | | | 'White Vision' x montana 'Praeflorens' |
| H. 'Jacqueline's Banner' Gil Jones/Tom Schmid 1999 | R | | dgr,we | | | "variegated Christmas Tree" x "variegated Christmas Tree" |
| H. 'Jade Beauty' Mark Zilis/T&Z Nursery 1988 | R | ML | dgr | | | 'Francee' sport |
| H. 'Jade Lancer' Chet W. Tompkins/P. & J. Ruh 2001 | R | ML | lgr,we | | | unknown |
| H. 'Jade Point' Lucille Simpers 1980 | R | S | gr | | | 'Fountain' hybrid |
| H. 'Jade Scepter' Mark Zilis/T&Z Nursery 1988 | R | S | gr | | | 'Golden Tiara' sport |
| H. 'Jadette' Ken Anderson 1982 | R | S | dgr,cre | | | unknown |
| H. 'Jambleliah' Paul Aden 1978 | R | M | str,gr,ch,y | | | 'Flamboyant' x 'High Fat Cream' |
| H. 'James A. Garfield' H. Sugita/P. & J. Ruh 2003 | R | | gr | R | | pycnophylla x kiyosumiensis |
| H. 'James Buchanan' H. Sugita/P. & J. Ruh 2005 | R | | gry | | | unknown |
| H. 'James Madison' H. Sugita/P. & J. Ruh 2005 | R | M | gr | PI | | longipes x pycnophylla |
| H. 'James Monroe' H. Sugita/P. & J. Ruh 2005 | R | | gry | | | unknown |
| H. 'James River' Alex Malloy 2005 | R | | gr | PU | | 'Pin Stripe Sister' seedling |
| H. 'Jane Ward' D. & J. Ward 1999 | R | | ly,dgre | | | 'Pin Stripe Sister' hybrid |
| H. 'Janet' Shugart/Russ O'Harra 1981 | R | SM | ch>w,gre | | | 'Fortunei' sport |
| H. 'Janet Day' Marge Soules 1996 | R | M | cr,dgre | | | 'Janet' sport |
| H. 'Janet Rugh' S. & S. Zolock 2001 | R | | str,gr,cr | | | unknown |
| H. 'Janet's Joy' R. Keller 2001 | R | ML | bl | | | 'Dorothy Benedict' sport |
| H. 'Jarett H. Park' S. Chamberlain 2003 | R | | dgr | | | 'Hirao Majesty' hybrid |
| H. 'Jason' R. Snyder 2002 | R | | gr,str,cr,cre | | | 'Silver Lance' sport |
| H. 'Java' M. Zilis 2003 | R | M | dblgr | | | 'Brim Cup' sport |
| H. 'Javelin' M. Laviana/Alex Malloy 2001 | R | SM | str,gr,crw | | | 'Lancifolia' sport |
| H. 'Jay B. Abendroth' S. Chamberlain 2001 | R | | blgr | | | 'Treasure' hybrid |
| H. 'Jay Jay' J. J. Grullemann/Peter Ruh 1994 | R | XL | blgr | | | sieboldiana hybrid |
| H. 'Jay P. Warren' S. Chamberlain 2004 | R | | | | | montana seedling |
| H. 'Jaz' G. Johnson 2004 | R | | goy | | | 'Sum and Substance' x yingeri |
| H. 'Jazz Matazz' R. Simmering 2000 | R | | str,gr,y,w | | | 'Fascination' hybrid |
| H. 'Jazzy' R. Simmering 2000 | R | | lgr,crwe | | | (x 'Fascination') sport |
| H. 'Jean Ferris Ruh' P. & J. Ruh 2005 | R | | ch,dgre | | | 'String Bikini' sport |
| H. 'Jelly Bean' Carolyn A. Harstad 1990 | R | S | str,gr,w,gre | | | 'Gum Drop' sport |
| H. 'Jelly Roll Blues' E. Elslager 2003 | R | | str,blgr,y,w | | | 'William Lachman' hybrid |
| H. 'Jen' G. Goodwin 2000 | R | | dgr,crwe | | | (x 'Yellow Splash') hybrid |
| H. 'Jennifer' Van Wade 1999 | R | | gr,cre | | | unknown |
| H. 'Jennifer Bailey' E. Lachman/T. Schmid 2001 | R | DS | gr,cre | | | unknown |
| H. 'Jennifer's Angel' J. Kerr 2000 | R | | str,dgr,lgr | | | 'Green Angel' sport |
| H. 'Jessica Lynn' Jim Husemann 2005 | R | L | gr,grye | | | 'Antioch' sport |
| H. 'Jewel of the Nile' Kevin Walek 2000 | R | M | blgr,irye | | | 'Dee's Golden Jewel' sport |
| H. 'Jim Cooper' Paul Aden 1982 | R | VL | y | | | 'Sum and Substance' hybrid |
| H. 'Jim Matthews' Mrs. J. W. Matthews/J. Matthews/B. Sligh 1998 | R | L | cr,blgre | | | sieboldiana hybrid |
| H. 'Jim Watkins' S. & S. Zolock 2004 | R | | | | | 'Love Pat' seedling |
| H. 'Jim Wilkins' Ralph and Dorothy Benedict 1990 | R | M | blgr,crwc | | | 'Dorothy Benedict' selfed |
| H. 'Jiminy Cricket' D. & J. Ward 2005 | R | D | lgr | | | 'Pin Stripe Sister' seedling |
| H. 'Jingle Bells' Vivian Grapes/AHS 1986 | R | SM | dgr | | | unknown |
| H. 'Jo Jo' David Stone/Peter Ruh 1987 | R | S | gr,crwe | | | unknown |
| H. 'Joanne Johnson ' I. Johnson 1999 | R | SM | blgr | | Y | tardiana hybrid |
| H. 'Johanne' Craig Ellyson/Peter Ruh 1989 | R | M | blgr | | | unknown |
| H. 'John Arva' S. & S. Zolock 2007 | R | | gr | | | 'Regal Rhubarb' hybrid |
| H. 'John James' S. & S. Zolock 2007 | R | | dgr | | | "seedling" x "seedling" |
| H. 'John Kulpa' J. Kulpa 1999 | R | | (ly>crw),gre | | Y | 'Seventh Heaven' sport |
| H. 'John Metzgar' S. & S. Zolock 2004 | R | | | | | ventricosa seedling |
| H. 'John Q. Adams' Unknown/P. & J. Ruh 2003 | R | | gry | | | unknown |
| H. 'John Wargo' Henry W. Weissenberger 1986 | R | SM | gr | PU | | nigrescens seedling |
| H. 'John Wells' S. & S. Zolock 2002 | R | | str,gr,w | | | 'Christmas Tree Gala' hybrid |
| H. 'Johnny Angel' Stuart Asch 2003 | R | | goy | | | unknown |
| H. 'Johnny Oh' J. Orlando 2003 | R | | gry,gre | | | 'June Bug' sport |
| H. 'Jolly Green Dwarf' Tony Avent 2006 | R | | gr | | | ventricosa seedling |
| H. 'Jolly Green Giant' Maxine Armstrong/AHS 1986 | R | XL | gr | | | unknown |
| H. 'Joseph' Bob Kuk 1990 | R | M | dgr | | | 'Josephine' sport |
| H. 'Josephine' Kuk's Forest 1987 | R | S | gr,nacrye | | | 'Neat Splash' hybrid |
| H. 'Jotunheim' Rod Lysne 2006 | R | ML | sibl | | | 'Versailles Blue' x 'Tokudama Flavocircinalis' |
| H. 'Journey's End' Hans Hansen 2004 | R | L | go,dgre | | | 'Choo Choo Train' sport |
| H. 'Joybells' Eldren W. Minks 1980 | R | M | y | | | 'Frances Williams' x 'Sunlight Sister' |
| H. 'Joyce Trott' Kevin C. Vaughn 1988 | R | SM | crw,dgre | | | 'Flamboyant' x 'Sum and Substance' |
| H. 'Joyful' M. Zilis/M. Vanous 2003 | R | SM | dgr,cre | | | 'Joyce Trott' sport |
| H. 'Jubilation' J. Wilkins/S. Wilkins 2000 | R | | dgr,grye | | | "HB-87-1" x 'Sagae' |
| H. 'Judi's Joy' Judi Frost/W. Zumbar 2003 | R | | gr,spe,y,w | | | 'Gold Standard' sport |
| H. 'Judy Rocco' Greg Johnson 2004 | R | | dgr | R | | ('Spritzer' x pycnophylla) x longipes f. hypoglauca |
| H. 'Judy's Amazing Grace' B. Treichel 2006 | R | | blgr | | | |
| H. 'Judy's Surprise' Kevin Walek 1996 | R | | | | | 'Rosanne' x 'Little White Lines' |
| H. 'Jujen' L. Jones 2002 | R | | y,crwe | | | 'Squash Casserole' sport |
| H. 'Julia' Peter White 1994 | R | M | blgr,we | | | 'Fortunei Hyacinthina' sport |
| H. 'Julia Ariana' R. Snyder 2003 | R | | str,gr,y,cr | | | 'Julia' sport |
| H. 'Julia Gaede' S. & C. Gaede 1994 | R | M | str,y,gr,w | | Y | plantaginea sport |
| H. 'Julia Hardy' Paul Aden 1978 | R | L | bl | | | 'Tokudama' x 'Big Mama' |
| H. 'Julie Ann' P. Banyai/D. Bachik 1995 | R | | blgr | | | unknown |
| H. 'Julie Morss' J. A. Morss 1983 | R | SM | y>gr,gre | | | 'Frances Williams' hybrid |
| H. 'Jumbo' A. Summers/P. Ruh 1997 | R | L | blgr | | | sieboldiana hybrid |
| H. 'June' Neo Plants Ltd. 1991 | R | SM | (lgr>y),blgre | | | 'Halcyon' sport |
| H. 'June Beauty' Wayside Gardens/AHS 1986 | R | ML | gr | | | unknown |
| H. 'June Bug' Ran Lydell 1999 | R | S | y,gre | | | 'Gold Edger' sport |
| H. 'June Dove' Marge Soules 1999 | R | M | blgr,lgre | | | unknown |
| H. 'June Fever' Jan Van den Top/Danny Van Eechaute 2004 | R | M | (y>yg),ble | | | 'June' sport |
| H. 'June Moon' Eleanor & William Lachman 1991 | R | ML | gr,crwe | | | unknown |
| H. 'June's Gold' E. Minks/P. Ruh 2000 | R | | goy | | | 'June' sport |
| H. 'Junior Miss' R. Klehm 1999 | R | S | dgr,crye | | | 'Sitting Pretty' sport |
| H. 'Jupiter' M. Zilis 2003 | R | ML | gr,ye | | | 'August Moon' sport |
| H. 'Jurassic Park' Rod Lysne 2006 | R | XL | dgr | | | "seedling" x "seedling" |
| H. 'Just So' Paul Aden 1986 | R | DS | y,blgre | | | 'Aden 421' x 'Little Aurora' |
| H. 'Justa Gigolo' Stuart Asch 2003 | R | | gr,str,w | | | "'Dorothy Benedict' seedling #95-18" seedling |
| H. 'Justice' Mark Zilis 2003 | R | | str,gr,w | | | 'Elatior' sport |
| H. 'Justinian' Alex Malloy 2002 | R | | str,gr,cr | | | unknown |