| I |
| Ice plant, Hardy, Delosperma cooperi |
| Ice plant, Hardy; Cloud-loving hardy ice plant, Delosperma nubigena |
| Ice plant; Cooper's hardy, Delosperma cooperi |
| Iceberg rose, Rosa 'KORturek' |
| Impatiens, Impatiens wallerana |
| Impatiens, New Guinea, Impatiens 'New Guinea' |
| Impatient rose, Rosa 'JACdew' |
| Imperatice Josephine rose, Rosa 'Francofurtana' |
| Indian grass, Sorphaatum nutans |
| Indian hemp, Apocynum cannabinum |
| Indian holly fern; Variegated holly fern, Arachiodes simplicior |
| Indian paintbrush; Scarlet painted-cup, Castilleja coccinea |
| Indian physic, Mountain; Bowman's root, Porteranthus trifoliatus (Gillenia trifoliate) |
| Indian physic; Bowman's root, Gillenia trifoliata = Porteranthus trifoliatus |
| Indian pink, Silene virginica |
| Indian quamash, Camassia cusickii; C. esculenta |
| Indian shot, Canna hybrids |
| Indian's virgin's bower, Clematis montana |
| Indian-pipe; Pinesap, Monotropa spp. |
| Indigo bush, Amorpha fruticosa |
| Indigo bush, Indigofera pseudotinctoria |
| Indigo, Bastard, Amorpha fruticosa |
| Indigo, Chinese, Indigofera decora |
| Indigo, False; Blue false indigo; Blue wild indigo, Baptisia australis |
| Indigo, False; White indigo, Baptisia alba |
| Indigo, False; Wild white indigo, Baptisia alba |
| Indigo, Himalayan, Indigofera heterantha |
| Indigo, Kirilow, Indigofera kirilowii |
| Indigofera, Indigofera amblyantha |
| Inkberry, Ilex glabra |
| Innerlight water lily, Nymphaea 'Innerlight' |
| Inspiration rose, Rosa 'Inspiration' |
| Intermediate shield fern; Evergreen wood fern; Fancy fern, Dryopteris intermedia; Dryopteris spinulosa var. intermedia |
| Interrupted fern; Clayton's fern, Osmunda claytoniana |
| Intrigue rose, Rosa 'JACum' |
| Iris, African, Dietes spp. |
| Iris, Bearded, Iris germanica |
| Iris, Butterfly, Dietes spp. |
| Iris, Butterfly, Moraea |
| Iris, Crested dwarf, Iris cristata |
| Iris, Dixie, Iris hexagona |
| Iris, Dutch, Iris hollandica |
| Iris, Dwarf, Iris reticulata |
| Iris, Dwarf, Iris reticulata, I. danfordiae, I. histroides |
| Iris, Dwarf; Crested dwarf iris, Iris spp. |
| Iris, English, Iris xiphiodes, I. angelica, I. latifolia |
| Iris, Iris cristata |
| Iris, Japanese roof, Iris tectorum |
| Iris, Japanese water, Iris ensata; I. kaempferi |
| Iris, Lamance; Short-stemmed iris, Iris brevicaulis |
| Iris, Larger blue flag, Iris versicolor |
| Iris, Roof; Wall iris, Iris tectorum |
| Iris, Southern blue flag, Iris virginica |
| Iris, Southern blue flag, Iris virginica |
| Iris, Species, Iris reticulata |
| Iris, White crested dwarf, Iris cristata alba |
| Ironweed, Tall; New York ironweed, Veronica noveboracensis |
| Ironwood, Carpinus betulus |
| Ironwood, Carpinus caroliniana |
| Isabelle Pring water lily, Nymphaea 'Isabelle Pring' |
| Ismene, Hymenocallis |
| Ispahan rose, Rosa 'Ispaham' |
| Italian bellflower, Campanula isophylla |
| Itea, Itea virginica |
| Ivy, Algerian, Hedera canariensis |
| Ivy, Algerian; Coney Island ivy, Hedera canariensis |
| Ivy, Boston, Parthenocissus tricuspidata |
| Ivy, Chochis, Hedera colchica |
| Ivy, Colchis; Persian ivy, Hedera colchica |
| Ivy, English, Hedera helix |
| Ivy, English, Hedera helix |
| Ixiolirion, Ixiolirion montanum (I. pallasii) |
| Ixora; Flame of the woods; Jungle flame, Ixora coccinea |