Plants: R
- Rabbiteye Blueberry Vaccinium virgatum Berry
- Radicchio Cichorium intybus Leafy
- Radish Raphanus sativus Root
- Ragged Robin Lychnis flos-cuculi Wildflower
- Railroad Vine Ipomoea pes-caprae Creeping perennial
- Rainbow Carrot Daucus carota subsp. sativus Root
- Rainier Cherry Prunus avium Tree fruit
- Ramps Allium tricoccum Allium
- Rangoon Creeper Quisqualis indica Vine
- Raspberry Rubus idaeus Berry
- Rattlesnake Master Eryngium yuccifolium Wildflower
- Red Barrenwort Epimedium × rubrum Creeping perennial
- Red Buckeye Aesculus pavia Flowering tree
- Red Buckwheat Eriogonum grande var. rubescens Wildflower
- Red Clover Trifolium pratense Legume
- Red Columbine Aquilegia canadensis Wildflower
- Red Currant Ribes rubrum Berry
- Red Elderberry Sambucus racemosa Flowering shrub
- Red Fescue Festuca rubra Grass
- Red Flag Bush Mussaenda erythrophylla Flowering shrub
- Red Ginger Alpinia purpurata Garden perennial
- Red Hot Poker Kniphofia uvaria Garden perennial
- Red Huckleberry Vaccinium parvifolium Berry
- Red Larkspur Delphinium nudicaule Wildflower
- Red Maple Acer rubrum
- Red Mulberry Morus rubra Tree fruit
- Red Osier Dogwood Cornus sericea Flowering shrub
- Red Passionflower Passiflora coccinea Fruiting
- Red Ribbons Clarkia concinna Wildflower
- Red Spider Lily Lycoris radiata Bulb
- Red Trillium Trillium erectum Wildflower
- Red Turtlehead Chelone obliqua Wildflower
- Red Valerian Centranthus ruber Garden perennial
- Red Yucca Hesperaloe parviflora Succulent
- Red-Flowering Currant Ribes sanguineum Flowering shrub
- Redbay Persea borbonia
- Redleaf Rose Rosa glauca Flowering shrub
- Redstem Ceanothus Ceanothus sanguineus Flowering shrub
- Redtop Agrostis gigantea Creeping perennial
- Redvein Enkianthus Enkianthus campanulatus Flowering shrub
- Redwood Ivy Vancouveria planipetala Creeping perennial
- Redwood Sorrel Oxalis oregana Creeping perennial
- Regal Geranium Pelargonium × domesticum Garden perennial
- Regal Lily Lilium regale Bulb
- Resinous Skullcap Scutellaria resinosa Garden perennial
- Reticulata Camellia Camellia reticulata Flowering shrub
- Reticulated Iris Iris reticulata Bulb
- Rhubarb Rheum rhabarbarum Leafy
- Rice Oryza sativa Grain
- Riddell's Goldenrod Oligoneuron riddellii Wildflower
- River Birch Betula nigra
- Riverbank Lupine Lupinus rivularis Wildflower
- Robb's Spurge Euphorbia amygdaloides var. robbiae Creeping perennial
- Robin's Plantain Erigeron pulchellus Creeping perennial
- Rock Cotoneaster Cotoneaster horizontalis Creeping perennial
- Rock Cress Aubrieta deltoidea Creeping perennial
- Rock Penstemon Penstemon rupicola Wildflower
- Rock Purslane Cistanthe grandiflora Succulent
- Rock Rose Pavonia Pavonia lasiopetala Garden perennial
- Rock Soapwort Saponaria ocymoides Creeping perennial
- Rocket Candytuft Iberis amara Garden annual
- Rocket Larkspur Consolida ajacis Garden annual
- Rocky Mountain Beeplant Cleome serrulata Wildflower
- Rocky Mountain Columbine Aquilegia coerulea Wildflower
- Rocky Mountain Iris Iris missouriensis Wildflower
- Rocky Mountain Penstemon Penstemon strictus Wildflower
- Roman Chamomile Chamaemelum nobile Herb
- Roof Iris Iris tectorum Garden perennial
- Rose Campion Lychnis coronaria Garden perennial
- Rose Clover Trifolium hirtum Legume
- Rose Hip Rosa rugosa Fruiting
- Rose Mallow Hibiscus moscheutos Wildflower
- Rose of Sharon Hibiscus syriacus Flowering shrub
- Rose Spirea Spiraea douglasii Flowering shrub
- Rose Verbena Glandularia canadensis Garden perennial
- Rosea Ice Plant Drosanthemum floribundum Succulent
- Rosebay Rhododendron Rhododendron maximum Flowering shrub
- Roseleaf Sage Salvia involucrata Garden perennial
- Rosemary Salvia rosmarinus Herb
- Rosemary Grevillea Grevillea rosmarinifolia Flowering shrub
- Roseshell Azalea Rhododendron prinophyllum Flowering shrub
- Rosinweed Silphium integrifolium Wildflower
- Rosy Pussytoes Antennaria rosea Creeping perennial
- Rosy Sedge Carex rosea Grass sedge
- Rough Blazing Star Liatris aspera Wildflower
- Rough-Leaved Hydrangea Hydrangea aspera Flowering shrub
- Roughleaf Dogwood Cornus drummondii Flowering tree
- Roundhead Bushclover Lespedeza capitata
- Roundhead Prairie Clover Dalea multiflora
- Roundleaf Ragwort Packera obovata Creeping perennial
- Royal Azalea Rhododendron schlippenbachii Flowering shrub
- Royal Catchfly Silene regia Wildflower
- Royal Penstemon Penstemon speciosus Wildflower
- Royal Poinciana Delonix regia Flowering tree
- Rubber Rabbitbrush Ericameria nauseosa Flowering shrub
- Rue Ruta graveolens Flowering shrub
- Rue Anemone Thalictrum thalictroides Wildflower
- Runner Bean Phaseolus coccineus Legume
- Rupturewort Herniaria glabra Creeping perennial
- Rush Milkweed Asclepias subulata
- Russet Buffaloberry Shepherdia canadensis Berry
- Russian Sage Perovskia atriplicifolia Garden perennial
- Rusty Blackhaw Viburnum rufidulum Flowering shrub
- Rusty Foxglove Digitalis ferruginea Garden perennial
- Rutabaga Brassica napus Root
- Rydberg's Penstemon Penstemon rydbergii Wildflower
- Rye Secale cereale Grain