| M |
| Maackia amuremsis, Amur maackia |
| Maclura pomifera, Osage orange; Hedgeapple |
| Magnolia x loebneri, Loebner magnolia |
| Magnolia acuminata, Cucumbertree magnolia |
| Magnolia cylindrica, Cylindrical magnolia |
| Magnolia denudata = Magnolia heptapeta, Yulan magnolia |
| Magnolia fraseri, Fraser magnolia |
| Magnolia grandiflora 'Little Gem', Little Gem magnolia |
| Magnolia grandiflora, Southern magnolia |
| Magnolia hybrids, Hybrid magnolias |
| Magnolia kobus, Kobus magnolia |
| Magnolia liliflora, Lily magnolia |
| Magnolia macrophylla, Bigleaf magnolia |
| Magnolia sieboldii, Oyama magnolia |
| Magnolia stella, Star magnolia |
| Magnolia tripetala, Umbrella magnolia |
| Magnolia virginiana, Sweetbay magnolia; Swamp magnolia |
| Magnolia x 'Freeman', Freeman magnolia |
| Magnolia x soulangiana, Saucer magnolia |
| Magnolia zenii, Zen magnolia |
| Mahonia aquifolium, Oregon grape holly |
| Mahonia bealei, Leatherleaf mahonia |
| Mahonia fortunei, Chinese mahonia |
| Mahonia repens, Creeping mahonia |
| Mahonia repens, Creeping mahonia |
| Mahonia x media, Media mahonia |
| Mahonia x wagneri, Wagner mahonia |
| Maianthemum canadense, Canadian mayflower; False lily-of-the-valley |
| Majorana hortensis, Marjoram |
| Malope trifida, Mallow |
| Malus angustifolia, Southern crabapple |
| Malus halliana var. parkmanii, Parkman crabapple |
| Malus hupehensis, Tea crabapple |
| Malus hybrids, Crabapples |
| Malus sieboldii, Siebold crabapple |
| Malus yunnanensis, Yunnan crabapple |
| Malva moschata, Musk mallow |
|
Malvaviscus arboreus, Turk's turban |
| Mandevilla splendens, Mandevilla |
| Mandevilla x amabalis, Mandevilla |
| Marrubium vulgare, Horehound |
| Marshallia graminifolia, Marshallia; Grass-leaf Barbara's button |
| Marsilea mutica 'Variegata', Variegated water clover |
| Matelea carolinensis, Climbing milkweed |
| Matricaria recutita, Chamomile |
| Matteuccia struthiopteris; M. pennsylvanica; Pteris nodulosa, Ostrich fern |
|
Meconopsis betonicifolia, Blue poppy |
| Medeola virginiana, Indian cucumber-root |
| Melampodium paludosum, Melampodium |
| Melampyrum lineare, Cow wheat |
| Melampyrum pratense, Cow wheat |
| Melia azadarach, Chinaberry |
| Melica ciliata, Hairy melic grass |
| Melissa officinalis, Lemon balm |
| Mentha spicata, Spearmint |
| Mentha x piperita, Peppermint |
|
Mertensia virginica, Virginia bluebells |
| Mertensia virginica, Virginia cowslip; Mertensia; Virginia bluebells |
| Metasequoia glyptostroboides, Dawn redwood |
| Michelia figo, Banana shrub |
| Michelia yunnanensis, Yunnan banana shrub |
| Microbiota decussata, Cypress; Siberian cypress; Russian arborvitae |
| Microbiota decussata, Russian arborvitae |
| Milla, Mexican star; Starlikes |
| Mimulus ringens var. ringens, Monkey flower |
| Mimulus ringens, Lavender musk |
| Mimulus x hybridus, Monkey flower |
| Mina lobata, Ipomoea lobata, Firecracker vine; Spanish flag |
| Minuartia verna spp. caespitosa, Moss sandwort |
| Minuartia verna ssp. caespitosa, Moss sandwort |
| Mirabilis jalapa, Four-o'clock |
| Miscanthus floridulus, Giant miscanthus |
| Miscanthus sinensis 'Goliath', Goliath miscanthus |
| Miscanthus sinensis 'Gracillimus', Maiden grass |
| Miscanthus sinensis 'Morning Light', Morning Light miscanthus |
| Miscanthus sinensis 'Sarbonde', Sarbonde miscanthus |
| Miscanthus sinensis 'Silberfeder', Silver feather miscanthus |
| Miscanthus sinensis 'Strictus', Porcupine grass |
| Miscanthus sinensis 'Yaku Jima', Dwarf miscanthus; Yaku Jima miscanthus |
| Miscanthus sinensis 'Zebrinus', Zebra grass |
| Miscanthus sinensis var. condensatus 'Cabaret', Cabert miscanthus |
| Miscanthus sinensis var. condensatus 'Cosmopolitan', Cosmopolitan miscanthus |
| Miscanthus sinensis, Variegatus, Variegated miscanthus |
| Miscanthus sisnensis Hinjo (Little Mickey), Compact zebra grass; Little Mickey miscanthus |
| Miscanthus sisnesis 'Adagio', Adagio miscanthus |
| Miscanthus transmorrisonensis, Taiwanese miscanthus |
| Mitchella repens, Partridge berry; Twinberry |
| Mitella diphylla, Bishops cap; Miterwort; Two-leaf miterwort |
| Molina caerulea subsp. arundinacea, Tall purple moor grass |
| Molina caerulea, Purple moor grass |
| Molucella laevis, Bells-of-Ireland |
| Momordica balsamina, Bitter melon; Balsam apple |
| Monarda didyma, Bee balm |
| Monarda didyma, Crimson bee-balm |
| Monarda media, Purple bergamont |
| Monarda punctata, Spotted horsemint |
| Monarda spp., Bee-balm; Oswego tea |
| Monotropa spp., Indian-pipe; Pinesap |
| Moraea, Peacock flower; Butterfly iris |
| Morus australis 'Unryo', Contorted mulberry |
| Muhlenbergia capillaris, Gulf muhly; Pink hair grass; Pink muhly; Mule grass |
| Muhlenbergia lindherimeri, Lindheimer's muhly |
|
Muscari armeniacum, Grape hyacinth |
|
Muscari azureum (Hyacinthella azurea), Grape hyacinth |
| Muscari botryoides 'Album', Grape Hyacinth |
|
Muscari comosum 'Plumosum', Grape Hyacinth |
| Myosotis scorpioides, Forget me not |
| Myosotis scorpioides, Water forget-me-not |
| Myosotis sylvatica, Forget-me-not |
| Myrica cerifera, Southern waxmyrtle |
| Myrica cerifera, Southern waxmyrtle |
| Myrica heterophylla, Swamp bayberry |
| Myrica pensylvanica, Northern bayberry |
| Myrica pensylvanica, Northern bayberry |
| Myriophyllum aquaticum, Parrot feather |