| Hostaname | RG | SZ | Leaf color | P | F | Origin |
| H. 'X Factor' Dick & Jane Ward 2013 | R | | blgr | | | 'Too Darn Hot' seedling |
| H. 'X-cellent' Doug & Mardy Beilstein 2018 | R | SM | crw,blgre | | | |
| H. 'X-rated' Ron Simmering 2001 | R | | w,gre | | | 'X-ray' sport |
| H. 'X-ray' Ron Simmering 2000 | R | | grw,gre | | | 'Gold Edger' sport |
| H. 'Xanadu' Alex Malloy 2000 | R | | w,blgre | PI | | 'Island Charm' sport |
| H. 'Xanadu Paisley' Virginia & Brian Skaggs 2000 | R | M | lgr,str,mot,dgr | | | 'August Moon' sport |
| H. 'Xcuse Me' Don Dean 2020 | R | | gr | R | N | 'Crimson Desire' x 'Night Flight' |
| H. 'Xela' Jim Hartmann 2003 | R | ML | gr,grye | | | 'August Moon' sport |
| H. 'Xerxes' Alex Malloy 2002 | R | S | dgr,str,w | | | 'Crepe Suzette Streaked' seedling |
| H. 'Xiangfei' Yantai Agricultural Science & Technical Institute 2020 | R | | gr>y | | Y | 'Royal Standard' x 'Summer Fragrance' |
| H. 'Xmas' Jeff Kerr 2000 | R | M | gr,cre | | | 'Moon Glow' sport |
| H. 'Xtraordinary' Steve Zolock 2010 | R | | dgr | PU | | 'Riptide' hybrid |