| Lamiastrum 'Herman's Pride' | False Lamium |
| Lamium 'Beacon Silver' | Dead Nettle |
| Lamium 'Golden Anniversary' | Dead Nettle |
| Lamium 'Orchid Frost' | Dead Nettle |
| Lamium 'White Nancy' | Dead Nettle |
| Lathyrus latifolius | Everlasting Sweet Pea |
| Lathyrus vernus | Everlasting Sweet Pea |
| Laurus nobilis | Bay Tree |
| Lavandula a. 'Buena Vista' | Lavender |
| Lavandula a. 'Hidcote Superior' | Lavender |
| Lavandula a. 'Jean Davis' | Lavender |
| Lavandula a. 'Martha Roderick' | Lavender |
| Lavandula a. 'Munstead' | Lavender |
| Lavandula a. 'Richard Grey' | Lavender |
| Lavandula a. 'Twickle Purple' | Lavender |
| Lavandula a. 'Vera' | Lavender |
| Lavandula dentata 'Lambikins' | Lavender |
| Lavandula s. 'Kew Red' | Lavender |
| Lavandula s. 'Quasti' | Lavender |
| Lavandula 'Sawyers' | Lavender |
| Lavandula 'Silver Edge' | Lavender |
| Lavandula x i. 'Alba' | Lavender |
| Lavandula x i. 'Grosso' | Lavender |
| Lavandula x i. Provence' | Lavender |
| Lavatera arborea 'Variegata' | Mallow |
| Lavatera 'Bredon Springs' | Mallow |
| Lavatera 'Red Rum' | Mallow |
| Lavatera thuringiaca 'Barnsley' | Mallow |
| Lavatera thuringiaca 'Barnsley Baby' | Mallow |
| Leontopodium alpinum | Edelweiss |
| Leptinella squalida 'Platt's Black' | New Zealand Brass Buttons |
| Lespedeza bicolor | Bush Clover |
| Leucanthemum s. 'Aglaia' | Shasta Daisy |
| Leucanthemum s. 'Becky' | Shasta Daisy |
| Leucanthemum s. 'Marconi' | Shasta Daisy |
| Leucanthemum s. 'Snowcap' | Shasta Daisy |
| Leucanthemum s. 'Summer Snowball' | Shasta Daisy |
| Leucothoe fontanesiana 'Rainbow' | Leucothoe |
| Lewisia columbiana v. rupicola | Lewisia, Quill-leaf |
| Lewisia cotyledon 'George Henley' | Bitterroot |
| Lewisia cotyledon 'Hybrid Mix' | Bitterroot |
| Lewisia cotyledon 'Regenbogen' | Bitterroot |
| Lewisia longipetala 'Little Plum' | Bitterroot |
| Liatris spic. 'Floristan Violet' | Blazing Star |
| Liatris spic. 'Floristan Weiss' | Blazing Star |
| Liatris spic. 'Kobold' | Blazing Star |
| Ligularia d. 'Dark Beauty' | Ligularia |
| Ligularia d. 'Desdemona' | Ligularia |
| Ligularia dentata 'Britt-Marie Crawford' | Ligularia |
| Ligularia dentata 'Othello' | Ligularia |
| Ligularia palmatiloba | Ligularia |
| Ligularia przewalskii | Ligularia |
| Ligularia s. 'The Rocket' | Ligularia |
| Ligularia tussilaginea 'aureomaculata' | Leopard Plant |
| Limonium latifolium | Statice |
| Lindernia grandiflora | Blue Moneywort |
| Liriope muscari 'Big Blue' | Lily-turf |
| Liriope muscari 'Okina' | Frosted Monkey Grass |
| Liriope spicata | Lily-turf |
| Lithodora d. 'Grace Ward' | Lithodora |
| Lobelia c. | Cardinal Flower |
| Lobelia cardinalis | Cardinal Flower |
| Lobelia 'Crown Royal' | Cardinal Flower |
| Lobelia f. 'Queen Victoria' | Cardinal Flower |
| Lobelia 'Monet Moment' | Cardinal Flower |
| Lonicera n. 'Baggesen's Gold' | Box Honeysuckle |
| Lonicera nitida 'Lemon Beauty' | Box Honeysuckle |
| Lunaria annua | Money Plant |
| Lupinus 'Gallery Blue' | Lupine |
| Lupinus 'Gallery Mix' | Lupine |
| Lupinus 'Gallery Yellow' | Lupine |
| Lupinus 'Minarette Mix' | Lupine |
| Lupinus 'Morello Cherry' | Lupine |
| Lupinus 'Russell Hybrids' | Lupine |
| Lychnis 'Gardener's World' | Rose Campion |
| Lychnis 'Jenny' | Rose Campion |
| Lycopodium obscurum | Princess Pine |
| Lysimachia atropurpurea 'Beaujolais' | Loosestrife |
| Lysimachia cil. 'Firecracker' | Loosestrife |
| Lysimachia clethroides | Gooseneck Loosestrife |
| Lysimachia nummularia 'Aurea' | Golden Creeping Jenny |
| Lysimachia p. 'Alexander' | Loosestrife |
| Lysimachia punctata 'Golden Alexander' | Loosestrife |
| Macleaya cordata | Plume Poppy |
| Macleaya microcarpa 'Kelway's Coral Plume' | Plume Poppy |
| Magnolia grandiflora 'Edith Bogue' | Magnolia, Evergreen |
| Magnolia grandiflora 'Ferruguinea' | Magnolia, Evergreen |
| Magnolia grandiflora 'Little Gem' | Magnolia, Evergreen Dwarf |
| Magnolia 'Yellow Lantern' | Magnolia, Yellow |
| Mahonia nervosa | Oregon Grape |
| Mahonia reptans | Creeping Mahonia |
| Maianthemum dilatatum | False Lily of the Valley |
| Malva alcea 'Fastigiata' | Mallow |
| Malva sylvestris mauritiana | Mallow |
| Malva sylvestris 'Zebrina' | Mallow |
| Marshallia grandiflora | Giant Barbara's Button |
| Marsilea mutica | Water Clover, Floating |
| Marsilea quadrifolia | Water Clover, Upright |
| Matteuccia struthiopteris | Ostrich Fern |
| Matteuccia struthiopteris 'The King' | Jumbo Ostrich Fern |
| Mazus reptans | Mazus |
| Mazus reptans 'Albus' | Mazus |
| Meconopsis betonicifolia | Himalayan Blue Poppy |
| Meconopsis grandis | Himalayan Blue Poppy |
| Meehania cordata | Creeping Mint |
| Melinis nerviglumis 'Pink Crystals' | Ruby Grass |
| Mentha requienii | Corsican Mint |
| Menyanthes trifoliata | Bogbean |
| Microlepia strigosa | Lace Fern |
| Mimulus guttatus | Monkey Flower |
| Miscanthus s. 'Zebrinus' | Eulalia Grass |
| Miscanthus var. 'Purpurascens' | Eulalia Grass |
| Molinia arundinacea 'Skyracer' | Purple Moor Grass |
| Molinia caerulea 'Variegata' | Purple Moor Grass, Variegated |
| Monarda d. 'Blue Stocking' | Bee Balm |
| Monarda d. 'Colrain Red' | Bee Balm |
| Monarda d. 'Jacob Cline' | Bee Balm |
| Monarda d. 'Marshall's Delight' | Bee Balm |
| Monarda d. 'Petite Delight' | Bee Balm |
| Monarda d. 'Raspberry Wine' | Bee Balm |
| Monarda didyma 'Pink Supreme' | Bee Balm |
| Monarda f. 'Claire Grace' | Bee Balm |
| Monarda 'On Parade' | Bee Balm |
| Musa basjoo | Banana, Hardy |
| Musa sikkimensis | Banana, Darjeeling |
| Musa sumatrana 'Zebrina' (Rojo) | Banana, Blood |
| Musella lasiocarpa | Banana, Hardy Yellow |
| Myosotis s. 'Victoria Indigo-Blue' | Forget-Me-Not |
| Myosotis scorpioides 'Snowflakes' | Water Forget-Me-Not |
| Nassella tenuissima | Mexican Feather Grass |
| Nepeta f. 'Six Hills Giant' | Catmint |
| Nepeta f. 'Walker's Low' | Catmint |
| Nymphoides crenata | Yellow Snowflake |
| Oenanthe javanica 'Flamingo' | Variegated Water Celery |
| Oenothera berlandieri 'Siskiyou' | Evening Primrose |
| Oenothera fruticosa 'Sonnenwende' | Sundrops |
| Oenothera macrocarpa (syn. Missouriensis) | Ozark Sundrops |
| Oenothera macrocarpa 'Comanche Campfire' | Sundrops |
| Oenothera tetragona 'Fireworks' | Evening Primrose |
| Onoclea sensibilis | Sensitive Fern |
| Ophiopogon japonicus 'Nanus' | Mondo Grass, Dwarf |
| Ophiopogon japonicus 'variegata' | Mondo Grass, Variegated |
| Ophiopogon p. 'Ebony Night' | Mondo Grass, Black |
| Ophiopogon p. 'Nigrescens' | Mondo Grass, Black |
| Origanum l. 'Hopley's Purple' | Oregano, Ornamental |
| Origanum l. 'Rosenkuppel' | Oregano, Ornamental |
| Origanum r. 'Kent Beauty' | Oregano, Ornamental |
| Origanum 'Santa Cruz' | Oregano, Ornamental |
| Origanum 'White Anniversary' | Oregano, Ornamental |
| Orontium aquaticum | Golden Club |
| Osmunda cinnamomea | Cinnamon Fern |
| Osmunda regalis | Royal Fern |
| Oxalis crassipes 'Alba' | Wood Sorrel |
