Last updated October 1, 2009
| Name | Family | Nativity |
| Haageocereus acranthus | Cactaceae | Peru |
| Haageocereus acranthus ssp. olowinskianus | Cactaceae | Peru |
| Haageocereus albispinus | Cactaceae | Peru |
| Haageocereus chosicensis x Borzicactus sp. | Cactaceae | |
| Haageocereus fascicularis | Cactaceae | Chile |
| Haageocereus pacalaensis v. pseudoversicolor | Cactaceae | Peru |
| Haageocereus pseudomelanostele | Cactaceae | Cen Peru |
| Haageocereus sp. | Cactaceae | |
| Haageocereus versicolor | Cactaceae | N Peru |
| Haageocereus versicolor v. aureispinus | Cactaceae | Peru |
| Haemanthus albiflos | Amaryllidaceae | South Africa |
| Haemanthus coccineus | Amaryllidaceae | South Africa |
| Haemanthus sp. | Amaryllidaceae | |
| Hakea petiolaris | Proteaceae | W Australia |
| Hakea suaveolens | Proteaceae | W Australia |
| Halleria lucida | Scrophulariaceae | Tropical & S Africa |
| Halocarpus bidwilli | Podocarpaceae | New Zealand |
| Hardenbergia violacea cv. Happy Wanderer | Fabaceae | |
| Harrisia aboriginum | Cactaceae | United States(Florida) |
| Harrisia martinii | Cactaceae | Argentina |
| Harrisia sp. | Cactaceae | |
| Harrisia tetracantha | Cactaceae | Bolivia |
| Hatiora salicornioides | Cactaceae | Brazil |
| Hatiora sp. | Cactaceae | |
| Hauya elegans v. hauya | Onagraceae | Mexico |
| Hauya sp. | Onagraceae | |
| Haworthia angustifolia v. liliputana | Asphodelaceae | South Africa |
| Haworthia chloracantha v. subglauca | Asphodelaceae | South Africa |
| Haworthia coarctata v. greenei | Asphodelacaea | South Africa |
| Haworthia cooperi | Asphodelacaea | South Africa |
| Haworthia correcta | Asphodelaceae | South Africa |
| Haworthia cymbiformis | Asphodelaceae | South Africa |
| Haworthia cymbiformis v. translucens | Asphodelaceae | South Africa |
| Haworthia divergens | Asphodelacaea | South Africa |
| Haworthia fulva | Asphodelaceae | South Africa |
| Haworthia magnifica | Asphodelacaea | South Africa |
| Haworthia magnifica v. | Asphodelaceae | South Africa |
| Haworthia margaritifera v. major hybrid | Asphodelaceae | |
| Haworthia mirabilis ssp. mundula cv. Batwings | Asphodelaceae | South Africa(W. Cape Province) |
| Haworthia musculina | Asphodelaceae | South Africa |
| Haworthia nigra v. | Asphodelaceae | South Africa |
| Haworthia nigra v. rynveldtii | Asphodelaceae | South Africa |
| Haworthia nitidula | Asphodelaceae | South Africa |
| Haworthia obtusa | Asphodelaceae | South Africa |
| Haworthia obtusa v. pilifera | Asphodelaceae | South Africa |
| Haworthia planifolia f. planifolia | Asphodelaceae | South Africa |
| Haworthia reinwardtii v. zebrina | Asphodelaceae | South Africa |
| Haworthia reticulata v. subregularis | Asphodelaceae | South Africa |
| Haworthia ryderiana | Asphodelaceae | Southern Africa |
| Haworthia sordida v. agavoides | Asphodelacaea | South Africa |
| Haworthia sordida v. agavoides | Asphodelaceae | South Africa |
| Haworthia sp. | Asphodelacaea | |
| Haworthia translucens ssp. tenera cv. Anemone | Asphodelaceae | South Africa |
| Haworthia transluscens ssp. tenera | Asphodelacaea | South Africa |
| Haworthia truncata | Asphodelaceae | |
| Haworthia turgida v. erecta | Asphodelaceae | South Africa |
| Haworthia venosa | Asphodelaceae | South Africa |
| Haworthia viscosa | Asphodelaceae | South Africa |
| Hechtia argentea | Bromeliaceae | Cen Mexico |
| Hechtia argentea x tillandsioides | Bromeliaceae | |
| Hechtia carlsonii | Bromeliaceae | |
| Hechtia cv. Silverado | Bromeliaceae | |
| Hechtia gayii | Bromeliaceae | Mexico |
| Hechtia marnier-lapostollei | Bromeliaceae | Mexico |
| Hechtia rosea | Bromeliaceae | Mexico |
| Hechtia roseana | Bromeliaceae | Mexico |
| Hechtia sp. | Bromeliaceae | |
| Hechtia sp. | Bromeliaceae | Argentina |
| Hechtia sp. | Bromeliaceae | Mexico |
| Hechtia stenopetala | Bromeliaceae | Mexico |
| Hechtia tillandsioides | Bromeliaceae | Mexico |
| Hedera canariensis | Araliaceae | Spain(Canary Islands) |
| Hedera helix | Araliaceae | |
| Hedera helix | Araliaceae | Africa |
| Hedera helix cv. | Araliaceae | |
| Hedychium angustifolium cv. Peach | Zingiberaceae | |
| Hedychium coccineum | Zingiberaceae | Himalayas |
| Hedychium coccineum cv. Disney | Zingiberaceae | |
| Hedychium coccineum cv. Tara | Zingiberaceae | |
| Hedychium coronarium | Zingiberaceae | Asia |
| Hedychium cv. Ayo | Zingiberaceae | |
| Hedychium cv. Carnival | Zingiberaceae | |
| Hedychium cv. Double Eagle | Zingiberaceae | |
| Hedychium cv. Filagree | Zingiberaceae | |
| Hedychium cv. Fireworks | Zingiberaceae | |
| Hedychium cv. Gold Flame | Zingiberaceae | |
| Hedychium cv. Golden Glow | Zingiberaceae | |
| Hedychium cv. Kewense | Zingiberaceae | |
| Hedychium cv. Kinkaku | Zingiberaceae | |
| Hedychium cv. Luna Moth | Zingiberaceae | |
| Hedychium cv. Maiko Salmon Pink | Zingiberaceae | |
| Hedychium cv. Pink | Zingiberaceae | |
| Hedychium cv. Pink Flame | Zingiberaceae | |
| Hedychium cv. Pink Sparks | Zingiberaceae | |
| Hedychium cv. Pink V | Zingiberaceae | |
| Hedychium cv. Tropic Bird | Zingiberaceae | |
| Hedychium cv. White Starburst | Zingiberaceae | |
| Hedychium ellipticum | Zingiberaceae | N India |
| Hedychium gardnerianum | Zingiberaceae | India |
| Hedychium greenii | Zingiberaceae | W Bhutan |
| Hedychium hybrid #7 | Zingiberaceae | |
| Hedychium pradhanii | Zingiberaceae | India |
| Hedychium thrysiforme | Zingiberaceae | India |
| Hedyscepe canterburyana | Arecaceae | Australia(Lord Howe Is.) |
| Helianthemum cv. Apricot | Cistaceae | |
| Helianthocereus x Pseudolobivia sp. | Cactaceae | |
| Heliconia latispatha | Heliconiaceae | S Mexico to Cen America |
| Helictotrichon sempervirens | Poaceae | Europe |
| Heliotropium arborescens | Boraginaceae | |
| Heliotropium arborescens cv. Alba | Boraginaceae | |
| Helleborus argutifolius | Ranunculaceae | Corsica, Sardinia |
| Helleborus niger | Ranunculaceae | Europe |
| Helleborus x hybridus | Ranunculaceae | |
| Hemerocallis cv. Lavender Dew | Hemerocallidaceae | |
| Hemerocallis cv. Little Bobo | Hemerocallidaceae | |
| Hemerocallis cv. Old Adage | Hemerocallidaceae | |
| Hemerocallis cv. Orange Crush | Hemerocallidaceae | |
| Hemerocallis cv. Peggy’s Pink | Hemerocallidaceae | |
| Hemerocallis cv. Rosella Sheridan | Hemerocallidaceae | |
| Hemerocallis cv. Russian Rhapsody | Hemerocallidaceae | |
| Hemerocallis cv. Tiny Pumpkin | hemerocallidaceae | |
| Hemerocallis cv. Yellow Kiss | Hemerocallidaceae | |
| Heteromeles arbutifolia | Rosaceae | California |
| Heteromeles arbutifolia cv. Davis Gold | Rosaceae | |
| Heteromeles arbutifolia v. macrocarpa | Rosaceae | |
| Heteromeles arbutifolia v. macrocarpa | Rosaceae | California |
| Heuchera cv. Carmel | Saxifragaceae | |
| Heuchera cv. Crimson Curls | Saxifragaceae | |
| Heuchera cv. Lillian’s Pink | Saxifragaceae | |
| Heuchera cv. Santa Ana Cardinal | Saxifragaceae | |
| Heuchera maxima | Saxifragaceae | S California(Channel Is.) |
| Hibbertia aspera | Dilleniaceae | SE Australia |
| Hibbertia cuneiformis | Dilleniaceae | Australia |
| Hibbertia dentata | Dilleniaceae | E Australia |
| Hibiscus rosa-sinensis | Malvaceae | |
| Hibiscus splendens | Malvaceae | Australia(Queensland, NSW) |
| Hibiscus syriacus | Malvaceae | |
| Hibiscus trionum | Malvaceae | Old World Tropics |
| Himalayacalamus hookerianus | Poaceae | E Himalayas |
| Hippeastrum x cv. San Antonio Rose | Amaryllidaceae | |
| Hippeastrum x cv. Voodoo | Amaryllidaceae | |
| Histiopteris incisa | Dennstaedtiaceae | Tropics |
| Hohenbergia correia-araujoi | Bromeliaceae | Brazil |
| Hohenbergia leopold-horstii | Bromeliaceae | Brazil |
| Hohenbergia ramageana | Bromeliaceae | Brazil |
| Hohenbergiopsis guatemalensis | Bromeliaceae | Guatemala |
| Houttuynia cordata | Saururaceae | Asia |
| Houttuynia cordata cv. Chameleon | Saururaceae | |
| Howea belmoreana | Arecaceae | Lord Howe Island |
| Howea forsteriana | Arecaceae | Australia(Lord Howe Is.) |
| Howea forsteriana | Arecaceae | Lord Howe Is. (Aus.) |
| Hydrangea cv. Lacecap | Saxifragaceae | |
| Hydrangea macrophylla cv. Glory Blue | Saxifragaceae | |
| Hydrocotyle vulgaris | Hydrocotylaceae | Europe |
| Hylocereus costaricensis | Cactaceae | Costa Rica |
| Hylocereus purpusii | Cactaceae | Mexico |
| Hylocereus undatus | Cactaceae | Tropical America |
| Hymenosporum flavum | Pittosporaceae | E Australia |
| Hypolepis glandulifera | Dennstaedtiaceae | Australia |
| Hypolepis hostilis | Dennstaedtiaceae | American Tropics |
| Hypoxis sp. | Hypoxidaceae | Argentina |
| Hyptis emoryi cv. Silver Lining | Lamiaceae |
