Hippeastrum puniceum
Amaryllis Lily
Hippobroma longiflora
Star of Bethlehem
Holmskioldia sanguinea
Chinese Hat Plant
Homalanthus populifolius
Bleeding Heart
Hopea ferrea
Malut
Hordeum distichon
Two-rowed Barley
Hordeum murinum
Wall Barley
Hordeum secalinum
Meadow Barley
Hornungia alpina
Perrenial Hutchinsia
Hornungia petraea
Hutchinsia
Humulus lupulus
Hop
Hyacinthoides hispanica
Spanish Bluebell
Hyacinthoides italica
Italian Bluebell
Hyacinthoides non-scripta
Bluebell
Hyacinthoides x massartiana
Garden Bluebell
Hydrangea macrophylla
Hydrangea
Hydrocotyle hirta
Hydrocotyle vulgaris
Marsh Pennywort
Hylotelephium telephium
Orpine
Hymenocallis fragrans
Spider Lily
Hymenocallis littoralis
Beach Spider Lily
Hypericum elodes
Marsh St John's-wort
Hypericum hirsutum
Hairy St John's-wort
Hypericum humifusum
Trailing St John's-wort
Hypericum maculatum
Imperforate St John's-wort
Hypericum perforatum
Perforate St John's-wort
Hypericum pulchrum
Slender St John's-wort
Hypochaeris maculata
Spotted Cat's-ear
Hypochaeris radicata
Cat's-ear
Hypopitys monotropa
Yellow Bird's-nest
Hyptis capitata
False Ironwort
Iberis amara
Wild Candytuft
Illecebrum verticillatum
Coral-necklace
Impatiens balsamina
Garden Balsam
Impatiens glandulifera
Indian Balsam
Impatiens noli-tangere
Touch-me-not Balsam
Indigofera hirsuta
Hairy Indigo
Ipomoea carnea
Pink Morning Glory
Iris foetidissima
Stinking Iris
Iris pseudacorus
Yellow Iris
Isatis tinctoria
Woad
Isolepis setacea
Bristle Club-rush
Ixora chinensis
Chinese Ixora
Jacobaea aquatica
Marsh Ragwort
Jacobaea vulgaris
Common Ragwort
Jasione montana
Sheep's-bit
Jatropha integerrima
Peregrina
Juglans regia
Walnut
Juncus acutus
Sharp Rush
Juncus articulatus
Jointed Rush
Juncus bufonius
Toad Rush
Juncus compressus
Round-fruited Rush
Juncus effusus
Soft-rush
Juncus gerardii
Saltmarsh Rush
Juncus inflexus
Hard Rush
Juncus squarrosus
Heath Rush
Juncus tenuis
Slender Rush
Justicia brandegeeana
Shrimp Plant
Justicia croceochlamys
Water-willow
Justicia fulvicoma
Mexican Plume
Kickxia elatine
Sharp-leaved Fluellen
Kleinhovia hospita
Guest Tree
Knautia arvensis
Field Scabious
Koenigia polystachya
Himalayan Knotweed
Laburnum anagyroides
Laburnum
Lactuca saligna
Least Lettuce
Lactuca serriola
Prickly Lettuce
Lactuca virosa
Great Lettuce
Lagerstroemia speciosa
Giant Crepe-myrtle
Lamiastrum galeobdolon
Yellow Archangel