Helleborus foetidus
Stinking Hellebore
Helleborus viridis
Green Hellebore
Helminthotheca echioides
Bristly Oxtongue
Helosciadium inundatum
Lesser Marshwort
Helosciadium nodiflorum
Fool's-water-cress
Heracleum mantegazzianum
Giant Hogweed
Heracleum sphondylium
Hogweed
Hesperis matronalis
Dame's-violet
Hevea brasiliensis
Pará Rubber Tree
Hibiscus tiliaceus
Sea Hibiscus
Hieracium argillaceum
Southern Hawkweed
Hieracium daedalolepioides
Petite-leaved Hawkweed
Hieracium inspissatum
Crass-leaved Hawkweed
Hieracium repandulare
Repand-leaved Hawkweed
Hieracium sect. Hieracioides
Hieracium sect. Oreadea
Hieracium sect. Sabauda
Hieracium sect. Stelligera
Hawkweed (Stelligera)
Hieracium subbritannicum
Hippeastrum puniceum
Amaryllis Lily
Hippophae rhamnoides
Sea-buckthorn
Hippuris vulgaris
Mare's-tail
Hirschfeldia incana
Hoary Mustard
Honckenya peploides
Sea Sandwort