- H & R Ballard.
- H D R Malcolm
- H, D F A
- H. A. Allen (Firm)
- H. A. Halbert (Firm)
- H. A. Halbert Seed Co.
- H. A. L. (Henry Astbury Leveson), 1828-1875
- H. A. Moyer Carriages (Syracuse, N.Y.)
- H. A. Puffer (Firm)
- H. A. Terry (Firm)
- H. Austin Co.,
- H. B. Burdick's Seed House.
- H. B. Fancher & Son,
- H. B. Romaker (Firm),
- H. B. Williams (Firm)
- H. C. Bateham (Firm)
- H. C. Carter (Firm)
- H. Cannell & Sons.
- H. Correvon & Fils.
- H. Dekort & Son Nursery,
- H. E. Chitty (Firm)
- H. E. Morrow (Firm)
- H. Ernest Conwell, Inc.
- H. F. Bente (Firm)
- H. F. Reeder (Firm)
- H. F. Schaan (Firm),
- H. G. Heberling (Firm)
- H. G. Norton (Firm)
- H. Harrington & Co.
- H. House & Co.
- H. J. Baker Nurseries.
- H. J. Ohms, Inc.
- H. J. Weber & Son.
- H. J. Weber & Son's Nurseries.
- H. J. Weber & Sons Nursery Company.
- H. Jay Welcher (Firm)
- H. Joseph Merrion (Firm)
- H. K. Lewis & Co.,
- H. K. Lewis and Company,
- H. Kempf (Firm)
- H. Kohankie & Son.
- H. L. Baake & Son Nurseries.
- H. L. Bauer & Son.
- H. L. Pearcy Nursery Co.,
- H. L. Woehler Co.
- H. M. Sandborn (Firm)
- H. M. Simpson & Sons.
- H. McConochie (Firm)
- H. N. Camp (Firm)
- H. P. Albaugh (Firm)
- H. P. Chenoweth (Firm),
- H. Patterson & Sons.
- H. Perry & Sons.
- H. Plath & Son.
- H. Plath (Firm)
- H. Post and Company.
- H. R. McNair (Firm)
- H. Roy Mosnat (Firm)
- H. S. Anderson (Firm)
- H. Schroeder (Firm)
- H. Schuett (Firm)
- H. Van Buskirk (Rocky Ford, Colo.)
- H. Van Buskirk Seed Co.
- H. W. Williams & Sons (Firm).
- H. Weber & Sons.
- H. Yoshiike (Firm)
- H., A E
- H., C D
- H., H T
- H., Review By: M A
- H., T E
- H.A. Albyn & Sons.
- H.A. Albyn Nursery.
- H.A. Allen (Firm)
- H.A. Brown & Son.
- H.A. Brown (Firm)
- H.A. Dunn (Firm),
- H.A. Hyde (Firm)
- H.A. Hyde Company,
- H.A. Hyde Company.
- H.A. Terry (Firm)
- H.A. Zager (Firm)
- H.B. Hartline Farm. Nursery Division,
- H.B. Pierce & Son.
- H.B. Scammell and Son.
- H.B. Williams (Firm)
- H.B. Williams (Firm),
- H.C. & F.M. Hatten.
- H.C. & J.B Agnew.
- H.C. Austin Dahlia Farm.
- H.C. Brose (Firm)
- H.C. Carey & I. Lea (Firm)
- H.C. King & Sons.
- H.C. Krueger, Hawaiian Imports,
- H.D. Garwood Seed Co.
- H.D. Garwood Seed Company.
- H.D. Richardson & Company,
- H.E. Chriswell (Firm)
- H.E. Fiske Seed Co.
- H.E. Fiske Seed Company.
- H.E. Hooker & Brothers.
- H.E. Hooker Company.
- H.E. Meader (Firm)
- H.E. Meader (Firm),
- H.E. Merrell Nursery Co.
- H.F. Burt (Firm)
- H.F. Chase (Firm)
- H.F. Hertzog (Firm)
- H.F. House & Company.
- H.F. Perry & Sons.
- H.F. Reeder (Firm)
- H.F. Webster (Firm)
- H.G. Faust & Co.
- H.G. German Seeds, Inc.,
- H.G. Hastings and Company (Ga.)
- H.G. Hastings Co.
- H.G. Hastings Co.
- H.G. Monce (Firm)
- H.H. Benning (Firm)
- H.H. Berger & Co.
- H.H. Berger & Company.
- H.H. Knight (Firm)
- H.H. Pedersen Fruit & Plant Farm,
- H.H. Robens (Firm)
- H.H. Withrow Co.
- H.H. Withrow Company.
- H.J. Adams & Son.
- H.J. and Alfred Mitting's Nurseries.
- H.J. and Otis Brabham.
- H.J. Backes (Firm)
- H.J. Champion & Son.
- H.J. Mueller & Son.
- H.J. Nitchman (Firm)
- H.J. Schild (Firm)
- H.J. Walrath & Sons,
- H.J. Walrath & Sons.
- H.J. Weber & Son's Nurseries.
- H.J. Weber & Sons Nursery Co.
- H.J. Weber & Sons Nursery Company.
- H.J. Westerhoven (Firm),
- H.J. Zack Co.
- H.L. Baake & Son.
- H.L. Clark (Firm)
- H.L. Fox Nursery and Landscape Service.
- H.L. Holmes (Firm)
- H.L. Larson Rhododendrons (Nursery),
- H.L. Maas & Sons,
- H.L. Pearcy Nursery Company,
- H.M. Barrett & Son.
- H.M. Franklin & Co.
- H.M. Franklin & Company.
- H.M. Hudelson (Firm)
- H.M. Miller (Firm)
- H.M. Sanborn (Firm)
- H.M. Simpson & Sons.
- H.M. Simpson Co.
- H.M. Taylor (Firm)
- H.M. Thompson & Son.
- H.M. Weil Seed Co.
- H.M. Weil Seed Store.
- H.M. Weil's Seed Store.
- H.N. Gage Co.
- H.N. Smith (Firm)
- H.P. Albaugh (Firm),
- H.P. Langdon & Son.
- H.P. Sass (Firm)
- H.P. Simpson (Firm)
- H.P. Winter (Firm)
- H.P. Wisehart Nursery,
- H.R. Bassler (Firm)
- H.R. Chapman (Firm)
- H.R. Lawrence (Firm)
- H.R. Lawrence (Firm),
- H.R. Mosnat (Firm)
- H.R. Parker (Firm)
- H.R. Schaan (Firm),
- H.S. Bay (Firm)
- H.S. Bossart and Company
- H.S. Graves (Firm)
- H.S. Jackson (Firm)
- H.S. Wiley & Son.
- H.S. Wiley (Firm)
- H.T. Coe (Firm)
- H.T. Harmon & Co.
- H.V. Lawrence (Falmouth, Mass.)
- H.V. Lawrence (Falmouth, Mass.),
- H.W. Blowers (Firm)
- H.W. Buckbee (Firm)
- H.W. Gordinier & Sons.
- H.W. Groschner (Firm)
- H.W. Jenkins & Son.
- H.W. Jenkins (Firm)
- H.W. Jenkins.
- H.W. Johnston (Firm)
- H.W. Koerner (Firm)
- H.W. Mann (Firm)
- H.W. Rice & Co.
- H.W. Stevens (Firm)
- H.W. West (Firm)
- H.W. Williams & Sons (Firm)
- H.W. Williams & Sons.
- H.W. Wilson Company.
- Ha, Dongsoo
- Ha, Bui Thu
- Ha, Hong Bich
- Ha, Ngoc Linh
- Ha, Nguyen Hai
- Ha, Sangwoo
- Ha, Thi Dung
- Haack, Bob.
- Haack, Carlos G. Herrero
- Haack, Paul M.
- Haack, Robert A.
- Haacke, J Douglas
- Haacke, Wilhelm, 1855-1912
- Haacke, Wulf D
- Haaf, Erwin
- Haaf, Thomas
- Haaff, H. H.
- Haaften, Caroline van
- Haag, Christian
- Haag, Johann Georg
- Haag, Kim H.
- Haag, Richard W.
- Haag, Taiana
- Haag, Wendell R
- Haag, William George, 1910-2000
- Haage & Schmidt.
- Haage, Friedrich Adolph 1796-1866
- Haagen-Smit, A. J. (Arie Jan), 1900-1977
- Haagenson, Philip L.
- Haagner, Alwin (Alwin Karl), 1880-1962
- Haagner, Alwin C
- Haagner, Anna
- Haagner, Gerald
- Haag-Rutenberg, Georg
- Haak, Cornelis (Leiden)
- Haak, Dirk (Ii, Leiden)
- Haak, J.
- Haake, Bernhard
- Haake, H. C.
- Haake, H. C., Mrs.
- Haan, D. Bierens de (David Bierens), 1822-1895
- Haan, Henri Rudolph Mari de.
- Haan, W. de (Willem), 1801-1855
- Haapala, Jaana
- Haar, D. ter (Dick) 1860-1905
- Haar, Gary L. ter
- Haarhoff, P J
- Haarlem. Koloniaal Museum.