Common names: H
- habanero
- hackberry
- hair grass
- hairgrass
- hairpin banksia
- hairy alpen rose
- hairy alumroot
- hairy beard tongue
- hairy lungwort
- hairy mountain mint
- hairy poppy
- hakea wattle
- Halberd willow
- Hamilton's spindle tree
- handkerchief tree
- hard fern
- hard shield fern
- hardneck garlic
- hardy begonia
- hardy Chinese orchid
- hardy cranesbill
- hardy dwarf broom
- hardy fuchsia
- hardy ice plant
- hardy impatiens
- hardy kiwi
- hardy summer gloxinia
- hardy swamp lily
- hare's ear
- Hare's foot clover
- Harison's yellow rose
- harlequin blueflag
- harlequin flower
- harlequin glory bower
- Harry Lauder's walking stick
- hart's tongue fern
- Hartweg's beard tongue
- Hawkesbury daisy
- hawksbeard
- hawkweed
- hawkweed oxtongue
- hawthorn
- hawthorn-leaf maple
- hay-scented orchid
- hazel
- hazelwort
- head lettuce
- heart leaf bergenia
- heart's ease
- heartleaf iceplant
- heartsease
- heath
- heath aster
- heath dog violet
- heath speedwell
- heath spotted orchid
- heath-leaved chaetopappa
- heather
- heavenly bamboo
- heavenly blue speedwell
- hedge bindweed
- hedge hyssop
- hedgerow cranesbill
- Helen Wilson's rose
- heliotrope
- hellebore
- hemlock
- hemp
- hemp agrimony
- hen and chicken fern
- henbane
- henbane bell
- Henry's honeysuckle
- Henry's lily
- Henry's lime
- herb gerard
- herb of grace
- herb of immortality
- herb paris
- herb robert
- Hercules all heal
- heron's bill
- herring bone cotoneaster
- hiba
- hickory
- Highland doghobble
- hill cherry
- Himalayan balsam
- Himalayan bergenia
- Himalayan birch
- Himalayan blue poppy
- Himalayan cedar
- Himalayan cotoneaster
- Himalayan creeper
- Himalayan hazel
- Himalayan honeysuckle
- Himalayan indigo
- Himalayan knotweed
- Himalayan mayapple
- Himalayan meadow primrose
- Himalayan peony
- Himalayan tree cotoneaster
- Himalayan viburnum
- Hinoki cypress
- hoarhound
- hoary alyssum
- hoary cress
- hoary mugwort
- hoary plantain
- hoary stock
- hog peanut
- hog's fennel
- Hokkaido squash
- holly
- holly oak
- holly olive
- holly osmanthus
- hollyhock
- hollyleaf sweetspire
- hollyleaved barberry
- holy basil
- holy flax
- Hondo spruce
- honesty
- honey locust
- Honey-scented heath
- honeypot dryandra
- honeysuckle
- hooded-leaf pelargonium
- hoof fungus
- hop
- hop clover
- hop hornbeam
- hop tree
- horehound
- hornbeam
- hornbeam maple
- horned maple
- horned pansy
- horned poppy
- horned spurge
- hornpoppy
- horse chestnut
- horse mint
- horseradish
- horseshoe vetch
- horsestail
- hosta
- hot pepper
- hound's tongue
- Houpu magnolia
- houseleek
- Howell's violet
- Huangshan magnolia
- hulled wheat
- hummingbird fuchsia
- Hungarian blue grass
- Hungarian clover
- Hungarian daisy
- Hungarian lilac
- Hungarian oak
- Hungarian thyme
- Hungarian widow flower
- hyacinth
- hyacinth bean
- hybrid black poplar
- hydrangea
- hyssop