| U Zbiroha | B Dec LB W/R. | Nak | 1953 | 20 mm | |
| U. 9. | C L. | Jin | 1926* | Catteleya L. | |
| U. S. A. | C Or. | Bru | 1932* | Breck '33/ enormous Or. | |
| Uberrasschung | Unk | 1942* | |||
| Uchuu | OO6 | AA FD R. | Hff | 1989 | ADS Nov '57/Lt. Rose R. to Vermilion /11x5",5'/85.8 |
| Ucitel Josef Mazanek | 370 | BB C LB Y/Pk. | Ost | 1955 | Salmon, Y. center /14 mm |
| Uddel | 446 | M SC R. | Unk | 1966 | Lt. Brick R. / 3 1/2",2', IR says Fl. |
| Uebermut | C Bi R/W. | Unk | 1921 | Amaranth R., W. tips | |
| Ueli | 214 | B FD V DkR/Y. | Etr | 1949 | Brownish R., speckled gold |
| Uerdingen | Or. | Sao | 1965* | Pure Or. | |
| Ugleinixe | C Pk. | Mcz | 1924 | LaFrance Pk. | |
| Uhland | Sur | 1898 | |||
| Uhu | 703 | S Or. | Mrj | 1939 | Or. Y., Scarlet Zone |
| Uitblinker (Uitblinder) | 275 | B C Bi | Mrj | 1965* | Green Shoots '65 |
| Uiver | SC Y. | Mrj | 1958 | ||
| Ujjala | A Dec R. | Mrj | 1994* | IDA '94/Brt Rr. | |
| Ukraine | O22 | AA ID Y. | Unk | 1990 | LBD '90, Lt. Primrose Y./ 12x8",85.6,87.0(2),87.08.88.0.90.0 |
| Ukraine Free | 207 | B FD DkR. | Hmt | 1994 | 85.4 |
| Ukraine Kiev | 228 | B ID L. | Cru | 1995 | ADS '95 |
| Ukraine Kolomya | 314 | BB FD V W/DkR. | Cea | 1998 | ADS '96/5 3/4 x 4 1/2"/85.67 |
| Ula | 508 | Ba L. | Bny | 1964 | |
| Ulan | 515 | Ba Bi L/W. | Unk | 1985 | RHS |
| Ulanova | B Dec Br. | Wes | 1938* | ||
| Ulick | BB Dec DB W/Pr. | Ost | 1969* | A. M. (g) 1925 | |
| Ulla | 192 | A (L)Fl. | Prb | 2003 | ADS Dec. Bul. '02'86.33 |
| Ulli | 728 | MS L. | Ldy | 1940* | Purplish L. |
| Ulloa | ID LB Y/R. | Ldy | 1958* | Dcd 1957, Creamy Y. suffused R. | |
| Ullswater | 404 | B FD Pk. | Ldy | 1956 | Bronzy Pk./ 6" |
| Ulrike | Dec Or. | Ldy | 1964* | ||
| Ulster Beauty | BB Dec Pk. | Unk | 1924 | ||
| Ulster Dawn | BB Dec LB Y/Pk. | Key | 1926 | ||
| Ulster Pride | 350 | BB SC LB Y/L. | Hea | 1966 | |
| Ulster Sunset | 350 | BB SC LB Y/Or. | Llo | 1967 | |
| Ulswater | Bei | 1942* | |||
| Ultimatum | DB Pk/R. | Clc | 1966 | F. C. C. 1865, IR says Bi but color description does not support | |
| Ultra Violet | 268 | B C(L) L. | Unk | 1963* | Maritz says Hea's |
| Ulva Quarrel | O35 | AA ID Bi R/W. | Ans | 1968 | Brt. Lt. R. w Large W. tips, Geranium R w W. tips /11x6",5' |
| Ulysse | 549 | P Pr. | Pzz | 1953 | Cerise Pr. |
| Ulysses | Dec R. | Unk | 1915* | Deep Crimson | |
| Um no Maju | 222 | B ID Y. | Oln | 1965 | Maize Y. w Pk suffusion on Rev. /7",4' . |
| Umba | 709 | S Pr. | Cck | 1966 | |
| Umela | 522 | MB Y. | Oln | 1956 | 6 mm |
| Umpaque Delight | 507 | A SC Y. | Oln | 2001* | Elkhorn '01 |
| Umpqua Almen | O54 | BB (L) DB Y/Pr. | Oln | 2002 | Garden Valley '02 |
| Umpqua Charm | 753 | BB (L) LB Y/Or. | Oln | 2002 | Cruger '01 |
| Umpqua Delight | 162 | A C Y. | Oln | 1998 | ADS '97/85.0 |
| Umpqua Frosty | 401 | M FD W. | Oln | 2000 | ADS '99/85.0,89.3,89.0,86.3,86.0,85.8/ 3 x 2" |
| Umpqua Little Bits | 387 | BB (L) DkR. | Oln | 2003 | ADS Dec. Bul. '02/85.75,86.71,86.25/4' |
| Umpqua Luminous | 281 | B (L) W. | Oln | 2003 | ADS Dec. Bul. '02\5 1/2 x 3 1/2"/85.0 |
| Umpqua Magic | B (L) Fl.. | Vav | 2000 | ADS '99/4 1/2"/86.0 | |
| Umpqua Magic | B (L) Fl. | Exn | 2000 | ADS '99/86.0 | |
| Umpqua Special | 314 | BB FD V Or/R. | Hea | 1981 | Tangerine Or. streaked Cherry R. /5 1/2x3 3/4",4' -85.0 |
| Umque Sunrise | 313 | BB FD DB Y/Pr. | Aus | 1993 | 86.5 |
| Umucenym Detem | A Dec W. | Cea | 1948 | Pure W., 25 mm | |
| Un Espoir | 246 | B SC R. | Aus | 1977* | Scarlet Hues |
| Una | BB Dec R. | Unk | 1938* | H. C. (g) 1947 | |
| Una | 166 | A C R. | Unk | 1978* | Maritz Ltr '95/ Cerise |
| Una | 350 | BB C LB W/L. | Unk | 1968* | |
| Una Bennett | 265 | B C DPk. | Pzz | 1958* | G. Ryan 1958, Brt. Pk. |
| Una Dunn | 263 | B C Or. | Dpl | 1974* | Fitzpatrick 1974, Finely Quilled, Brt. Or. |
| Una Gregg | 122 | A ID Y. | Unk | 1981 | |
| Una Holland | 605 | WL DPk. | Meg | 1963* | Dan 1960, Fuchsia Pk. /4' |
| Unas | 268 | B C L. | Str | 1953 | 16 mm |
| Unas | 664 | Col Pk. | Unk | 1936 | |
| Uncertainty | 506 | Ba R. | Cum | 1975* | Dahlianews 1938, Mostly R. but now and then a W. petal |
| Uncle Clete | 427 | M ID DkR. | Chl | 1996 | TGR '95/86.5 |
| Uncle Dick | BB Dec Bi Or/W. | Unk | 1954 | A. M. (g) 1925 | |
| Uncle Dudley | IC Pr. | Yox | 1949 | Fuchsia Pr. | |
| Uncle Dudley | 175i | A IC Bi W/DkR. | Chl | 1947* | W. edged Wine |
| Uncle Ed | 203 | B FD Or. | Unk | 1981 | Apricot /8x5 1/2",4'-85.0 |
| Uncle Fred | 269 | B C Pr. | Chl | 1924 | |
| Uncle Jo | 103 | A FD Or. | Miy | 1977 | Lt. Indian Or. /9x6",4' -85.0 |
| Uncle Joe | 269 | B C Pr. | Con | 1949 | |
| Uncle Ray | 330 | BB ID DB | Unk | 1999* | ADS '01 |
| Uncle Robert | 103 | A FD Or. | Bax | 1978* | Carrot R. /8 1/4x6 1/4",4' - 85.17,85.25 |
| Uncle Sam | 409 | M FD Pr. | Hun | 1976 | 3 1/4x2",4' - 85.0,85.267,85.5 |
| Uncle Sam | ID Br. | Reed | 1949 | Autumn blend | |
| Uncle Tom | 407 | M FD DkR. | Unk | 1977* | 85.66 |
| Uncle Tom | 207 | B FD DkR. | Unk | 1967 | A. M. 1899, Almost black /7 1/2x3",2 1/2' |
| Uncle Tom | 207 | B FD DkR. | Neb | 1933* | Deep Garnet, almost black /7 1/2x3",5 1/2' |
| Uncle Tom | Dec DkR. | Unk | 1907 | Nearly Black | |
| Uncle Tom | 252 | B SC Fl. | Noi | 1967 | R. tipped gold /9x4 1/2" - 85.0(3) |
| Uncle Tom | 146 | A SC R. | Str | 1899 | |
| Uncle Tom | 407 | M FD DkR. | Lor | 1961 | |
| Uncle Walt | 131 | A ID Br. | Etr | 1944 | |
| Undaunted | 110 | A FD R. | Unk | 1954* | The Dahlia 1954, Blood R. |
| Undenloh | 248 | B SC L. | Mae | 1958* | |
| Underestimate | 254 | B SC V Pk/R. | Geo | 1977* | |
| Undine | 610 | WL LB W/L. | Unk | 1934 | Pinkish Lilac on W. |
| Undine | C Pk. | Bkl | 1940 | ||
| Undine | 401 | M FD W. | Sev | 1961* | |
| Undine | 541 | P W. | Lam | 1938* | |
| Unequalled | 242 | B SC Y. | Bao | 1883* | Indian Y. |
| Unermudlich | Y. | Bru | 1969* | ||
| Unforgettable | 365i | BB IC DPk. | Unk | 1958* | Brt. L. Pk./5x4",3' |
| Unicorn | 306 | BB FD R. | Vao | 1969* | |
| Unicum | C LB W/DPk. | Tur | 1935* | Milbee '35/ Rose w W. center | |
| Unicum | 350 | B SC LB Y/Pk. | Key | 1969* | Salmon Pk., Large Y. center, H. C. (g) 1932 |
| Unicum | 201 | B FD W. | Con | 1968* | |
| Union | SC L. | Bru | 1957 | ||
| Union Gap | 409 | M FD Pr. | Hug | 1992 | 85.5 |
| Union Jack | 715 | S Bi R/W. | Unk | 1931 | R w W. edges,3 1/2",3', Syn: STAR OF DENMARK, A. M. 1911 |
| Union Jack | C Bi R/W. | Unk | 1915* | Red tipped W. | |
| Unique | C Bi R/W. | Lam | 1919* | Deep R., tips W. | |
| Unique | 513 | Ba DB W/R. | Str | 1882 | F.C.C. 1868 |
| Unique | 510 | Ba LB Y/R. | Unk | 1840* | Florist's Guide, lt. Y., tipped w R./4-5' |
| Unique | 167 | A C DkR. | An40 | 1958* | Purplish R. /9x5",3 1/2' |
| Unique | 110 | A FD LB Or/R. | Key | 1975* | Spanish Or Center, to Carmine Rose Tips / 10x7",4' |
| Unique | 127 | A ID DkR. | Nuy | 1945* | Very fine Crimson maroon / 8" |
| Unique Dwarf | 712 | S Fl. | Hej | 1977 | RHS says Raiser is Ant. Nuyens ( maay be new) |
| Unit | 547 | P DkR. | Wfn | 1957 | Deep R. |
| United | BB Dec Bi R/W. | Bru | 1959* | ||
| United Colors | 310 | BB FD LB Y/Or/R. | Aus | 1991 | RHS sup 6/R. w Y. base outer, inner Reddish Or. w Y. base |
| United Nations | ID Y. | Etr | 1962* | Golden | |
| Univers | 250 | B SC LB W/Pk. | Aus | 1868 | |
| Universal | O46 | AA SC R. | Bru | 1967 | Lt. Salmon R. /11x7",4' |
| Universal | 263 | B C Or. | Wolf | 1946 | Y. tipped Peach giving a Burnt Or. effect/ 7x3",4' |
| Universum | 161i | A IC W. | Geo | 1958* | Bao 1958, Colossal and deep W./ 5' |
| Unley | BB C | Kap | 1990 | ||
| Unmatched | 341 | BB SC W. | Unk | 1968* | Pure W., Snowy W. /6x4", 4'-85.0 |
| Unschuld | SC W. | Unk | 1939* | ||
| Unser Peterle | C Br. | Jpo | 1962* | Salmon Pk. copper nuances | |
| Unusual | 270 | B C .LB Y/Or. | Jos | 1975* | Menzel List |
| Unwin Hybrids | Mae | 1935* | Mich Spec Bul # 266, Singles, various colors/12-18 " | ||
| Unworthy | 309 | BB FD Pr. | Exn | 1977 | |
| Unzen | 146 | A SC R. | Vnk | 1973 | Deep Salmon R. /4 1/2' / |
| Up Date | 148 | A SC L. | Exn | 1960 | 85.0,85.03 |
| Up to Date (Up-to-Date) | 350 | BB SC LB Br/Pk. | Lag | 1965* | Ancient Pk. overlaid Golden Apricot /5' |
| Upominka Na Ceskou Skalici | Dec Fl. | Tch | 1933 | Y. & Scarlet | |
| Upominka Na Lomnici Nad *** | C DkR. | Maek | 1927 | ***Popelkou, Brownish R. | |
| Upominka Na Pecin | Dec Y. | Aus | 1927 | ||
| Upominka Na Tyn Nad Vlavou | Dec Y. | Bren | 1930 | Creamy Y. | |
| Uppingham | 202 | M FD Y. | Bru | 1978* | C '79, Amber Y. /4 1/8",4' |
| Upton Sinclair | 445 | M SC DPk. | Non | 1975 | Deep Pk. w a somewhat darker center |
| Uralla Surprise | 261 | B C W. | Str | 1966* | Pure W. /7x3",4' |
| Uran | 346 | BB SC R. | Unk | 1985 | Czo list |
| Urania | 248 | B SC L. | Mann | 1956 | Mauve-Magenta |
| Uranie | C Or. | Unk | 1951 | Salmon-Or. | |
| Uranus | 174 | A C V W/R. | Bcg | 1961* | A. M. 1911, W. striped Crimson |
| Uranus | 375 | BB C Bi Or/W. | Bru | 1932* | Brownish Or., W. tips /5 3/4" |
| Uranus | 128 | A ID L. | Blf | 1945* | The very best and finest (blue) dahlia / 8" |
| Urara | M Bi W/R. | Str | 1955* | Pete's 1958, Pure W. w each petal heavily edged in blood R. | |
| Urchin | BB (L) DkR. | Dee | 1994 | ADS '95/ 6 x 3 1/2", 85.833 F** - full class. not given | |
| Urchin | 266 | B C R. | Unk | 1946 | |
| Urk | 351 | BB SC Br. | Unk | 1911 | Lt. Salmon Br./ 4 1/2",2' |
| Ursa Major | SC DB Y/R. | Bnk | 1961 | A. M. 1915 | |
| Ursala | Dec DkR. | Brl | 1964 | ||
| Ursel | Dec DkR. | Wer | 1942* | ||
| Ursla Senzone | 308 | BB FD L. | Dee | 1997* | Con '97/4 |
| Ursula | 426 | M ID R. | How | 1947* | Crimson, w Carmine Rev. Dwarf |
| Ursula | 210 | B FD LB W/Or. | Hff | 1975 | Czo list |
| Ursula | C LB Y/DPk. | Blo | 1915* | Greenish chrome tipped rose | |
| Ursula | Dec R. | Geo | 1957 | Lacquer R. | |
| Ursula | 550 | P LB W/Pk. | Unk | 1951* | Pure Pk., lighter center, very small |
| Ursula Concannon | 266 | B C R. | Unk | 1968* | Dry 1962, Carmine R. cutflower/ 4 1/2' |
| Ursula Spath (Späth) | Unk | 1991 | Jahrbuch 1990/1991 | ||
| Ursula Stanhope | 406 | M FD R. | Unk | 1915 | |
| Useful | 405 | M FD DPk. | Dpl | 1958* | A. M. 1912 |
| Useful | 545 | P DPk. | Kia | ]926* | Carmine Pk. |
| Useful | 507 | Ba DkR. | Unk | 1947 | S. C. C. 1863 |
| USK | 250 | B SC LB Y/Or. | Jpo | 1993* | J T '94 |
| Usk Orange | 503 | Ba Or. | Unk | 1863 | |
| Usmev | Dec Pk. | Dov | 1942 | ||
| Ustek | 342 | BB SC Y. | Est | 1977 | Czo list |
| Usugesho | 110 | A FD LB W/Pk. | Thm | 1998* | Winvhester Gardens Ltd. |
| Usushio | 149 | A SC Pr. | Flo | 1935* | Erk 1974 |
| Usvit | B Dec Pk. | Jin | 1945 | 18 mm | |
| Utah Heritage | 366 | BB C R. | Bru | 4964* | Jasper R. -85.25 |
| Ute | 668 | Col L. | Con | 1966* | Lilac |
| Utecha | 367 | BB C DkR. | Hff | 1951 | 15 mm |
| Utex | 264 | B C Pk. | Unk | 1957 | 16 mm |
| Utility | 310 | BB FD LB W/DPk. | Bru | 1912 | Vivid Pk., W. center. 5",4 1/2'-Now probably WL (610) |
| Utmost | 252 | B SC(L) Fl. | Unk | 1995 | ADS '95/ 86.0 |
| Uto | 242 | B SC Y. | Unk | 1951 | Old gold |
| Utopia | 270 | B C LB W/Pk. | Unk | 1957* | Pure Pk. w Lighter center /6x4",4' |
| Utrecht | O35 | AA ID Bi R/W. | Unk | 1965 | Brt. R., W. tips /11 1/2x7",3 3/4' |
| Uttu | 241 | B SC W. | Unk | 1955* | |
| Uxurdico | 549 | P Pr. | Pev | 1961* | |
| Uzo Shio | 170I | A IC LB | Unk | 1975* | Marshall 1975 |
| Uzon | 166 | A C R. | Frn | 1968 | Lt. Carmine Pk. blended w Salmon /5' |
| Uzushio | 149 | A SC Pr. | Bru | 1975* |