Humulus lupulus
Hop
Hyacinthoides hispanica
Spanish Bluebell
Hyacinthoides italica
Italian Bluebell
Hyacinthoides non-scripta
Bluebell
Hyacinthoides x massartiana
Garden Bluebell
Hydrocotyle vulgaris
Marsh Pennywort
Hylotelephium telephium
Orpine
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
Iberis amara
Wild Candytuft
Illecebrum verticillatum
Coral-necklace
Impatiens glandulifera
Indian Balsam
Impatiens noli-tangere
Touch-me-not Balsam
Iris foetidissima
Stinking Iris
Iris pseudacorus
Yellow Iris
Isatis tinctoria
Woad
Isolepis setacea
Bristle Club-rush