- Horr, Asa, 1817-1896
- Horr, Ella Louise,
- Horr, Worthie Harold 1891-
- Horra Ruiz, José Luis de la
- Horrall, Audrey D.
- Horrebow, Niels, 1712-1760
- Horrell, E. Charles
- Hörren, Thomas
- Horricks, J. S.,
- Horridge, Adrian
- Horridge, Frank.
- Horrn, Johan Laurentius, 1683-1741
- Horro, Juan
- Horrocks, Kiran Jonathan
- Horrocks, William Heaton, 1859-
- Hors, S L
- Horsák, Michal
- Horsäk, Michal
- Horsbkugh, Charles B
- Horsbrugh, Boyd Robert, 1871-1916
- Horsbrugh, Charles B
- Horsburgh, David B
- Horsburgh, J. 1791-1869
- Horsburgh, M
- Horsburgh, R L
- Horschelt, Theodor, 1829-1871
- Horseman, Nelson D.
- Horsemen, Dana Lee
- Horsfall, James G. (James Gordon), 1905-1995
- Horsfall, P F
- Horsfall, Peter
- Horsfall, R Bruce
- Horsfall, R. Bruce 1869-1948
- Horsfall, Thomas.
- Horsfall, William Robert, 1908-
- Horsfield, D
- Horsfield, David
- Horsfield, Herbert Knight.
- Horsfield, Janice
- Horsfield, T
- Horsfield, Thomas, 1773-1859
- Horsford, Barbara B.,
- Horsford, Eben N.
- Horsford, F. H.
- Horsford, F.H.
- Horsford, Frederick H.
- Horsford, Frederick Hinsdale, 1855-1923
- Horsford, Fred'k H.
- Horsford, William G.,
- Horsford, Wm. C.,
- Horsford's Nurseries.
- Horsley, Angela
- Horsley, Candace E.
- Horsley, J. W. (John William), 1845-1921
- Horsley, Jno. F.
- Horsley, Lee H.
- Horsley, Pam
- Horsley, Pamela
- Horsley, Victor, Sir, 1857-1916
- Horsley, Victor.
- Horsman, Matthew L.
- Horspool, R. P.
- Horsrrugh, Charles B
- Horst, A
- Horst, Gerhard van der
- Horst, H. L. A. Van Der.
- Horst, Lois
- Horst, R
- Horst, R R
- Hörstadius, S
- Hörstadius, Sven, 1898-1996
- Horstein, Irwin.
- Horstman, Brent H
- Horstman, Mark
- Horstmann, K
- Horstmann, Klaus
- Horstmann, Martin
- Horstmann, W
- Horsup, Alan
- Hort, Arthur, Sir, 1864-1935
- Horta, Claudia
- Horta, Gabriela Baeza
- Horta, Lília
- Horta, Nati
- Horta, P.A.
- Horta, Paulo
- Horta, Paulo A.
- Horta, Paulo Antunes
- Horta, Sebastián
- Hortal, Joaquín
- Horta-Puga, Guillermo
- Horta-Vega Jorge Víctor
- Horta-Vega, Jorge Victor
- Hortelano, Yolanda
- Hortelano-Moncada, Yolanda
- Hortenci, Luana
- Hortenstine, Charles Carpenter, 1919-
- Horthemels, Daniel,
- Horticultural Co. (Worcester, Mass.)
- Horticultural Company (Worcester, Mass.)
- Horticultural Society of London
- Horticultural Society of New York.
- Horticultural Society of Northern Illinois.
- Horticultural Society of Staten Island.
- Horton Greenhouse (Horton, Kan.)
- Horton Nurseries, Inc.,
- Horton, Bryony M
- Horton, Charles C
- Horton, Chris
- Horton, D R
- Horton, David
- Horton, David R
- Horton, David Robert
- Horton, Diana
- Horton, Diana G.
- Horton, Donald, 1910-
- Horton, Frances Belle,
- Horton, Frances C.,
- Horton, Frances C., Mrs.,
- Horton, G A N
- Horton, Horace Everett.
- Horton, J. R. (John Raymond), 1882-
- Horton, Jane,
- Horton, Jerome S. (Jerome Sweet), 1910-
- Horton, John
- Horton, John Raymond.
- Horton, L. J.
- Horton, P
- Horton, Peter
- Horton, Philippa
- Horton, Robert E. (Robert Elmer), 1875-1945
- Horton, Stephanie
- Horton, T R
- Horton, Tammy
- Horton, W
- Hortus Nurseries.
- Hortvet, Julius, 1863-1927
- Horvat, Bogdan
- Horvat, Laslo
- Horváth, Anna
- Horvath, David
- Horvath, Elizabeth
- Horváth, Enikő
- Horvath, Eric G
- Horvàth, Frank
- Horváth, Géza, 1847-1937
- Horváth, Győző
- Horváth, Győző F.
- Horváth, János, 1921-
- Horvath, L
- Horvath, Peter
- Horváth, Roland
- Horvath, S M
- Horváth, Soma
- Horvathova, Terezia
- Hörweg, Christoph
- Horwich, R H
- Horwich, Robert H
- Horwitz, Ellie.
- Horwitz, Joseph
- Horwitz, P
- Horwitz, Pierre
- Horwitz, Pierrs
- Horwitz, R C
- Horwood, A. R. (Arthur Reginald), 1879-1937
- Horwood, Denise
- Horyoak, D.T.
- Horyza, Chris.
- Hos, D
- Hosack, David, 1769-1835
- Hosagoudar, V B
- Hosaka, K.
- Hosaka, Kentaro
- Hosäus, Arnold.
- Hosbach, H A
- Hosch, H
- Hoschedè, M J-P
- Hoschke, F
- Hose, Bishop
- Hose, C
- Hose, Charles, 1863-1929
- Hose, G F
- Hose, Grant
- Hose, Grant C
- Hose, J E
- Hose, Jo Ellen
- Hosea Waterer (Firm)
- Hosek, Jan
- Hoseman, P
- Hosen, Iqbal
- Hosen, Md. Iqbal
- Hoser, R T
- Hoser, Raymond
- Hosetti, Basaling B
- Hosford, D R
- Hosford, F. H. (Frederick Hinsdale), 1855-1923
- Hosford, Harold V.
- Hosford, Ruby C.
- Hoshi, Motonori
- Hoshiba, MA.
- Hoshiba, Márcio Aquio
- Hoshimov, Hushbaht R.
- Hoshina, H
- Hoshina, Hideto
- Hoshino, Takuji
- Hoshino, Tamotsu
- Hoshino, Yoichiro
- Hoshizaki, Barbara J
- Hoshizaki, Barbara Joe
- Hosia, Aino
- Hosick, Howard L
- Hosie, A M
- Hosie, Andrew
- Hosie, Andrew M
- Hosie, D J
- Hosie, E.R.
- Hosie, Graham W
- Hosie, R. C. (Robert Christie)
- Hosier, L. B.
- Hosja, W
- Hosken, D J
- Hosken, Rev Bob
- Hoskin, C J
- Hoskin, Conrad
- Hoskin, Conrad J
- Hoskin, George P
- Hoskin, P W O
- Hoskin, Somsong P
- Hosking, Arthur Nicholas, 1874-
- Hosking, Florence
- Hosking, J S
- Hosking, John
- Hosking, John R
- Hosking, L F V
- Hosking, Lucy F V
- Hosking, Richard
- Hosking, T
- Hoskins, A. H., Captain, active 1872-
- Hoskins, A. L.
- Hoskins, Andrew
- Hoskins, Hannah M. J.
- Hoskins, Margaret Morris
- Hoskins, Megan
- Hoskins, Roy Graham, 1880-
- Hoskins, W. G. (William George), 1908-1992
- Hoskins, W. M. (William Muriece), 1896-1993
- Hoskinson, W S
- Hoskisson, Paul
- Hoskong, A C
- Hoskovec, Michal