| P |
| Pachysandra procumbens, Allegheny spurge |
| Pachysandra terminalis, Pachysandra |
| Paeonia hybrids, Peony |
| Pandorea pandorana, Pandora vine; Wonga-wonga vine |
| Panicum virgatum 'Cloud Nine', Tall switch grass |
| Panicum virgatum 'Hamelin', Hamelin; Dwarf fountain grass |
| Panicum virgatum 'Heavy Metal', Heavy Metal; Blue switch grass |
| Panicum virgatum 'Moudry', Moudry |
| Panicum virgatum, Switch grass |
|
Papaver somniferum, Opium poppy |
|
Papaver spp., Poppy |
| Parnassia asarifolia, Grass-of-parnassus; Kidney-leaf grass-of-parnassus |
| Paronychia kapela, Nailwort |
| Parrotia persica, Persian parrotia |
| Parrotiopsis jacquemontiana -- |
| Parthenium integrifolium, Wild quinine |
| Parthenocissus quinquefolia, Virginia creeper |
| Parthenocissus tricuspidata, Boston ivy; Japanese creeper |
| Passiflora incarnata, Passion flower; Maypops |
| Passiflora incarnata, Passion vine; Maypop |
| Paulownia tomentosa, Empress tree; Princess tree |
| Pedicularis canadensis, Lousewort; Wood betony |
| Pelargonium peltatum, Ivy geranium |
| Pelargonium spp., Scented geranium |
| Pelargonium x hortorum, Geranium |
| Pellaea falcata, Sickle fern |
| Pennisetum alopecuroides, Fountain grass |
| Pennisetum alopecuroides, Fountain grass |
| Pennisetum orientale, Oriental fountain grass |
| Pennisetum setaceum, Annual fountain grass; Crimson fountain grass |
| Pennisetum setaceum; P. macrostachynum, Purple fountain grass; Dwarf red fountain grass |
| Penstemon canescens, Beard-tongue; Penstemon |
| Penstemon cobaea, Cobaea beardtongue |
| Penstemon digitalis, Foxglove beardtongue; White beardtongue |
|
Penstemon spp., Bearded tongue |
| Pentas lanceolata, Pentas; Star cluster |
| Perilla frutescens, Perilla |
|
Perovskia atriplicifolia, Russian sage |
| Perovskia atriplicifolia, Russian sage |
| Persea borbonia, Redbay |
| Persea palustris, Swamp redbay |
| Petroselinum crispum, Parsley |
| Petunia x hybrida, Petunia |
| Phacelia bipinnatifida, Purple phacelia; Loose-flowered phacelia |
| Phacelia purshii, Miami mist, Scorpionweed |
| Phalaris arundarinacea, Ribbon grass |
| Phalaris arundinaera, Ribbon grass; Gardener's garters; Reed canary grass |
| Phaseolus coccineus, Scarlet runner bean |
| Phegopteris hexagonoptera; Thelypteris hexagonoptera, Broad beech fern; Southern beech fern |
| Phellodendron chinese, Chinese corktree |
| Phellodendron sachalinense, Sakhalin corktree |
| Phelloendro amurense, Amur corktree |
| Philadelphus coronarius, Sweet mockorange; Fragrant mock orange |
| Philadelphus delavayi, Mockorange |
| Philadelphus inodorus; P. hirsutus, Mock orange |
| Philadelphus inodorus; P. hirsutus, Mockorange |
| Philadelphus x 'Polar Star', Polar Star mockorange |
| Philadelphus x 'Snow Velvet', Snow Velvet mockorange |
| Philadelphus x lemoinei, Lemoinei mockorange |
| Philadelphus x virginalis, Virginal mockorange |
| Phlox carolina, Carolina phlox |
| Phlox divaricata, Blue phlox |
| Phlox glaberrima, Smooth phlox; Appalachian smooth phlox; Marsh phlox |
| Phlox paniculata, Fall phlox |
|
Phlox paniculata, Garden phlox |
| Phlox spp., Phlox |
| Phlox stolonifera, Creeping phlox |
| Phlox subulata, Moss-pink; Moss phlox |
| Phlox subulata, Thrift; Moss pink |
| Phormium texax, New Zeland flax |
| Photinia davidiana, Chinese photinia |
| Photinia glabra, Japanese photinia |
| Photinia serrulata, Chinese photinia; Oriental photinia |
| Photinia serrulata, Chinese photonia |
| Photinia villosa, Oriental photinia |
| Photinia x fraseri, Fraser photinia |
| Physocarpus opulifolius, Ninebark |
| Physocarpus opulifolius, Ninebark; Eastern ninebark |
|
Physostegia virginiana, Obedient plant |
| Physostegia virginianum, Obedient plant; False dragonhead |
| Phytolacca americana, Poke; Pokeweed |
| Picea abies 'Maxwellii', Maxwell's Norway spruce; Maxwell spruce |
| Picea abies 'Nidiformis', Birdsnest spruce |
| Picea abies 'Pumila Glauca' -- |
| Picea abies 'Pumila', Pumila Norway spruce |
| Picea abies cranstonii, Cranston spruce |
| Picea abies, Norway spruce |
| Picea asperata, Dragon spruce |
| Picea glauca 'Conica', Dwarf Alberta white spruce |
| Picea glauca 'Rainbow's End', Rainbow's End white spruce |
| Picea glauca, White spruce |
| Picea likiangensis var. purpurea, Likiang spruce |
| Picea mariana 'Nana', Dwarf black spruce; Blue nest spruce |
| Picea mariana, Black spruce |
| Picea omorika 'Nana', Dwarf Serbian spruce |
| Picea omorika, Serbian spruce |
| Picea orientalis 'Nana', Dwarf Norway spruce |
| Picea orientalis, Oriental spruce |
| Picea pungens 'Compacta', Dwarf spruce |
| Picea pungens 'Fat Albert', Fat Albert spruce |
| Picea pungens 'Mission Blue', Mission Blue spruce |
| Picea pungens, Colorado blue spruce |
| Picea rubens, Red spruce |
| Picea smithiana, Himalayan spruce; Morinda spruce |
| Picrasma ailanthoides, Indian quassiawood |
| Pieris floribunda, Fetter-bush; Mountain andromeda |
| Pieris floribunda, Mountain pieris |
| Pieris formosa var. forresti, Himalayan pieris |
| Pieris formosa, Himalayan pieris |
| Pieris japonica, Japanese pieris |
| Pieris x 'Bent Chandler', Bent Chandler pieris |
| Pieris x 'Brouwer's Beauty', Brouwer's Beauty pieris |
| Pilosella officinarum, Mouse-ear hawkweed |
| Pimpinella anisum, Anise |
| Pinckneya braceata, Fever tree; Poinsettia tree |
| Pinguicula spp., Butterwort |
| Pinguicula caerulea, Violet butterwort |
| Pinus aristata, Bristlecone pine |
| Pinus armandii, David's pine |
| Pinus banksiana, Jack pine |
| Pinus bungeana, Lacebark pine |
| Pinus cembra, Arolla pine; Swiss stone pine |
| Pinus densiflora 'Oculusdraconis', Dragon's-eye pine |
| Pinus densiflora 'Pendula', Weeping Japanese red pine |
| Pinus densifolia, Japanese red pine |
| Pinus echinata, Shortleaf pine |
| Pinus edulis,Pinyon pine |
| Pinus elliotii, Slash pine |
| Pinus flexilis, Limber pine |
| Pinus glabra, Walter's pine; Spruce pine |
| Pinus heldreichii var. leucodermis, Bosnian pine |
| Pinus heldreichii, Bosnian pine |
| Pinus korariensis 'Compact Glaucua', Compact Bosian pine |
| Pinus korariensis, Korean pine |
| Pinus monticola, Western white pine |
| Pinus mugo 'Mops', Mops mugo pine |
| Pinus mugo var. pumilio, Little mugo pine; Dwarf Swiss mountain pine |
| Pinus mugo, Mugo pine; Swiss mountain pine |
| Pinus nigra 'Hornibrookiana' -- |
| Pinus nigra, Austrian pine |
| Pinus palustris, Longleaf pine |
| Pinus parviflora, Japanese white pine |
| Pinus peucea, Balen pine; Macedonian pine |
| Pinus piaster, Cluster pine; Maritime pine |
| Pinus ponderosa var. scopulorum, Ponderosa pine |
| Pinus ponderosa, Ponderosa pine; Western yellow pine |
| Pinus rigida, Pitch pine |
| Pinus serotina, Pond pine |
| Pinus strobus 'Nana', Dwarf eastern white pine |
| Pinus strobus 'Ontario', Ontario white pine |
| Pinus strobus 'Pendula', Weeping white pine |
| Pinus strobus 'Radiata', Radiata white pine |
| Pinus strobus, Eastern white pine |
| Pinus sylvestris 'Abyns', Abyns Scotch pine |
| Pinus sylvestris 'Glauca Nana', Dwarf blue Scotch pine |
| Pinus sylvestris 'Hillside Creeper', Hillside Creeper pine |
| Pinus sylvestris 'Nana', Dwarf Scotch pine |
| Pinus sylvestris 'Watereri', Walter's pine |
| Pinus sylvestris, Scotch pine |
| Pinus taeda 'Dixie', 'Nana', Dwarf loblolly pine |
| Pinus taeda, Loblolly pine |
| Pinus thunbergiana 'Thunderhead', Thunderhead pine |
| Pinus thunbergiana, Japanese black pine |
| Pinus virginiana, Virginia pine |
| Pinus wallichiana, Himalayan pine; Butan pine |
| Pinus yunnanensis, Yunnan pine |
| Pistacia chinensis, Chinese pistache |
| Pistia stratiotes, Water lettuce |
| Pittosporum tobira, Japanese pittosporum |
| Platanthera (Habenaria) psycodes, Purple fringed orchid |
| Platanthera ciliaris = Habenaria ciliaris, Yellow fringed orchid |
| Platanthera orbiculata var. orbiculata, Large round-leaf orchid; Round-leaved orchis |
| Platanus occidentalis, Sycamore |
| Platanus orientalis (var. digitata), Oriental planetree |
| Platanus x acerifolia, London plane tree |
|
Platycodon grandiflorus, Balloon flower |
| Plectranthus argentatus, Silver plectranthus |
| Plectranthus fosteri 'Marginatus', Spur flower |
| Pleioblastus auricoma, Kanuro-zasa; Compact golden-striped bamboo |
| Pleiodlastus variegatus, Compact white-striped bamboo |
| Plumbago auriculata = P. capensis, Cape leadwort |
| Plumbago auriculata, Cape leadwort |
| Podocarpus macrophyllus var. maki, Shrubby podocarpus |
| Podophyllum peltatum, May-apple; Mandrake |
| Pogonia ophioglossoides, Rose crested orchid; Rose pogonia |
|
Polemonium spp., Jacob's ladder |
| Polianthes, Tuberose; Polyanthus lily |
| Poliothyrsis sinensis, Poliothyrsi |
| Polygala curtissii, Polygala; Curtiss' milkwort |
| Polygala lutea, Yellow milkwort; Orange milkwort |
| Polygonatum biflorum, Solomon's seal |
| Polygonatum humile, Dwarf Solomon's seal |
| Polygonella cuspidatum, Japanese knotweed |
| Polygonum aubertii, Silverlace vine; Fleece vine |
| Polygonum hydropiper, Smartweed; Water-pepper |
| Polygonum japonica, Low Japanese fleeceflower |
| Polygonum orientale, Gardengate; Kiss-me-over-the-garden-gate |
| Polygonum pennsylvanicum, Pennsylvania smartweed; Pink knotweed |
|
Polygonum spp., Knotweed |
| Polypodium polypodioides, Resurrection fern |
| Polystichum acrostichoides, Christmas fern |
| Polystichum braunii, Braum's holly fern |
| Polystichum polyblepharum, Korean tassel fern; Tassel fern; Japanese tassel fern; Bristle fern |
| Polystichum setiferum, Soft shield fern; Hedge fern |
| Polystichum tsus-simense, Tsu-sima holly fern; Korean rock fern |
| Poncirus trifoliata, Hardy orange; Trifoliate orange |
| Pontederia cordata alba, White pickerel weed |
| Pontederia cordata, Pickerel weed |
| Pontederia cordata, Pickerel weed |
| Populus deltoides, Eastern cottonwood; Eastern poplar |
| Populus nigra, Lombardy poplar |
| Porteranthus trifoliatus (Gillenia trifoliate), Mountain indian physic; Bowman's root |
| Portulaca grandiflora, Portulaca; Moss rose |
| Potentilla canadensis, Dwarf cinquefoil |
| Potentilla fruticosa, Shrubby potentilla; Shrubby cinquefoil |
| Potentilla fruticosa, Shrubby potentilla; Shrubby cinquefoil |
| Potentilla recta, Rough-fruited cinquefoil |
| Potentilla spp., Cinquefoil; Five fingers; Potentilla |
| Potentilla tridentata, Three toothed cinquefoil |
|
Potentilla x hybrida, Cinquefoil |
| Poterium sanguisorba, Salad burnet |
| Prenanthes altissima, Rattlesnake root; Tall white lettuce |
|
Primula veris, Cowslip primrose |
|
Primula x polyantha, Primrose |
| Prunella vulgaris, Heal all |
|
Prunella x webbiana, Self-heal |
| Prunus 'Okame', Okame cherry |
| Prunus americana, American plum; Wild plum |
| Prunus angustifolia, Chickasaw plum |
| Prunus caroliniana, Carolina cherry laurel |
| Prunus cerasifera, Purple leaf plum |
| Prunus glandulosa, Flowering almond |
| Prunus laurocerasus 'Otto Luken', Otto Luken cherry laurel |
| Prunus laurocerasus 'Zabeliana', Zabel's cherry laurel |
| Prunus laurocerasus, English laurel |
| Prunus lusitonica, Portugal laurel; Portuguese cherry laurel |
| Prunus mume, Flowering apricot |
| Prunus pennsylvanica, Fire cherry; Pin cherry |
| Prunus persica var. nucipersica 'White Glory', 'White Glory' weeping nectarine |
| Prunus persica, Corinthian hybrids |
| Prunus persica, Peach |
| Prunus sargentii, Sargent cherry |
| Prunus serotina, Wild Cherry; Black cherry |
| Prunus serrula, Papperbark cherry |
| Prunus serrulata 'Ukon', Ukon cherry |
| Prunus serrulata, Japanese cherry |
| Prunus subhirtella 'Autumnalis', Autumn blooming cherry |
| Prunus subhirtella, Higan cherry |
| Prunus virginia, Common chokecherry |
| Prunus x 'Whitecomb', Whitecomb cherry |
| Prunus x bilireana, Blireiana plum |
| Prunus x cistena, Purple leaf sand cherry |
| Prunus x cistena, Purple-leaf sand cherry |
| Prunus x yedoensis, Yoshino cherry |
| Pseudocydonia sinensis, Chinese quince |
| Pseudolaria kaempferx, Golden larch |
| Pseudolarix amabilis, Goldenlarch |
| Pseudotsya menziesii, Douglas fir |
| Ptelea trifoliata, Hoptree |
| Pteridium aquilinum var. psedocaudocanudatrum, Tailed bracken fern |
| Pteris nodulosa; Matteuccia pennsylvanica; M. struthiopteris, Ostrich fern |
| Pterocarya stenoptera, Chinese wingnut |
| Pteroceltis tartarinowii, Tara wingceltis |
| Pterostyrax corymbosa, Little epaulettetree |
| Pterostyrax hispidus, Epaulettetree |
|
Pulmonaria saccharata, Lungwort |
| Punica granatum, Pomegranate |
|
Puschkinia libanotica, Striped Squill |
| Pycnanthemum incanum, Hoary mountain-mint |
| Pycnanthemum muticum, Short toothed mountain-mint |
| Pycnanthemum tenuifolium, Narrow-leafed mountain-mint |
| Pyracantha 'Mohave', Mohave pyracantha |
| Pyracantha coccinea, Scarlet firethorn |
| Pyracantha koidzumii, Formosa pyracantha |
|
Pyrethrum roseum = Chrysanthemum coccineum, Pyrethrum |
| Pyrola elliptica, Shinleaf |
| Pyrola rotundifolia, Round-leafed pyrola |
| Pyrrosia hastata; P. tricuspis, Felt fern |
| Pyrrosia lingua, Tongue fern; Felt fern |
| Pyrus calleryana, Callery pear |
| Pyrus pyrifolia, Chinese sand pear |