| Angels Gilia | Gilia angelensis | Polemoniaceae | Phlox | Native, Common, Annual herb, typically blooms from February to April, Oak Woodland FebruaryMarchApril |
| Annual Coreopsis | Leptosyne bigelovii | Asteraceae | Sunflower | Endemic, Common, Annual herb, typically blooms from February to June, Oak Woodland FebruaryMarchAprilMayJune |
| Ashy Leaved Buckwheat | Eriogonum cinereum | Polygonaceae | Buckwheat | Native, Common, Shrub woody, typically blooms from June to October, coastal scrub and chaparral JuneJulyAugustSeptemberOctober |
| Baby Blue Eyes | Nemophila menziesii | Boraginaceae | Borage | Native, Uncommon, Annual herb, typically blooms from February to June, shady canyon slopes, meadows FebruaryMarchAprilMayJune |
| Beach Evening Primrose | Camissoniopsis cheiranthifolia | Onagraceae | Evening Primrose | Native, Common, Perennial , typically blooms from March to July, Coastal Strand MarchAprilMayJuneJuly |
| Bee Plant | Scrophularia californica | Scrophulariaceae | Figwort | Native, Uncommon, Perennial , typically blooms from April to July, sage, chaparral AprilMayJuneJuly |
| Big Pod Ceanothus | Ceanothus megacarpus | Rhamnaceae | Buckthorn | Endemic, Common, Shrub or Tree , typically blooms from January to March, Chaparral JanuaryFebruaryMarch |
| Bigberry Manzanita | Arctostaphylos glauca | Ericaceae | Heath | Native, Common, Shrub , typically blooms from December to March, woodland chapparal - northern slopes DecemberJanuaryFebruaryMarch |
| Birds Beak | Cordylanthus rigidus | Orobanchaceae | Broomrape | Native, Common, Annual herb, typically blooms from May to August, open chaparral, coastal sage MayJuneJulyAugust |
| Black Sage | Salvia mellifera | Lamiaceae | Mint | Native, Common, Shrub , typically blooms from April to July, Coastal Sage AprilMayJuneJuly |
| Bladderpod | Peritome arborea | Cleomaceae | Spider Flower | Native, Common, Shrub , typically blooms from January to December, Coastal Bluffs, hillsides, oak woodlands JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
| Blue Dicks | Dipterostemon capitatus | Themidaceae | Brodiaea | Native, Common, Perennial , typically blooms from December to May, Grasslands, Sage Scrub, open places in Chaparral DecemberJanuaryFebruaryMarch |
| Blue Larkspur | Delphinium parryi | Ranunculaceae | Buttercup | Native, Common, Perennial , typically blooms from March to May, Grasslands, edges or open spaces of Chaparral and Oak Woodland MarchAprilMay |
| Blue-Eyed Grass | Sisyrinchium bellum | Iridaceae | Iris | Native, Common, Perennial , typically blooms from March to June, Grasslands, Coastal Scrub or Woodlands MarchAprilMayJune |
| Brodiaea | Brodiaea terrestris | Themidaceae | Brodiaea | Native, Uncommon, Perennial , typically blooms from May to June, clay soils, grassy meadows MayJune |
| Bush Mallow | Malacothamnus fasciculatus | Malvaceae | Mallow | Native, Common, Shrub , typically blooms from January to December, Chaparral, Coastal Sage Scrub, disturbed soil JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
| Bush Poppy, Tree Poppy | Dendromecon rigida | Papaveraceae | Poppy | Native, Uncommon, Perennial , typically blooms from February to June, Chaparral FebruaryMarchAprilMayJune |
| Bush Sunflower | Encelia californica | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from December to August, Chaparral and Coastal Sage Scrub DecemberJanuaryFebruaryMarch |
| Calabazilla | Cucurbita foetidissima | Cucurbitaceae | Gourd | Native, Common, Perennial Vine , typically blooms from June to August, Sandy soil JuneJulyAugust |
| California Aster | Corethrogyne filaginifolia | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to November, chaparral, sage scrub, grasslands, oak woodlands MayJuneJulyAugustSeptemberOctoberNovember |
| California Brickellbush | Brickellia californica | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from July to November, open chaparral, coastal sage JulyAugustSeptemberOctoberNovember |
| California Buckwheat | Eriogonum fasciculatum | Polygonaceae | Buckwheat | Native, Common, Perennial , typically blooms from January to December, Chaparral, Coastal Sage Scrub, Desert Scrub JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
| California Buttercup | Ranunculus californicus | Ranunculaceae | Buttercup | Endemic, Uncommon, Perennial , typically blooms from February to May, Chaparral, Oak Woodland FebruaryMarchAprilMay |
| California Coffeeberry | Frangula californica | Rhamnaceae | Buckthorn | Native, Common, Shrub , typically blooms from May to July, Chaparral and coastal sage scrub MayJuneJuly |
| California Dodder | Cuscuta californica | Convolvulaceae | Morning Glory | Native, Common, Annual Vine herb, typically blooms from April to October, Chaparral AprilMayJuneJulyAugustSeptemberOctober |
| California Everlasting | Pseudognaphalium californicum | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from January to July, sage scrub JanuaryFebruaryMarchAprilMayJuneJuly |
| California Fuchsia | Epilobium canum | Onagraceae | Evening Primrose | Native, Common, Perennial , typically blooms from June to December, dry and/or rocky areas on slopes and in sage scrub JuneJulyAugustSeptemberOctoberNovemberDecember |
| California Goldenrod | Solidago velutina | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from July to November, coastal sage scrub, chaparral, oak woodlands JulyAugustSeptemberOctoberNovember |
| California Goldfields | Lasthenia californica | Asteraceae | Sunflower | Endemic, Common, Annual herb, typically blooms from March to May, meadows, hillsides MarchAprilMay |
| California Laurel | Umbellularia californica | Lauraceae | Laurel | Native, Common, Shrub or Tree , typically blooms from November to March, riparian NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJulyAugust |
| California Milkweed | Asclepias californica | Apocynaceae | Dogbane | Native, Common, Perennial , typically blooms from April to June, chaparral, open slopes AprilMayJune |
| California Plantain | Plantago erecta | Plantaginaceae | Plantain | Native, Common , Annual herb, typically blooms from March to April, Coastal Scrub, Open Areas MarchApril |
| California Poppy | Eschscholzia californica | Papaveraceae | Poppy | Endemic, Common, Annual herb, typically blooms from February to September, meadows, coastal sage scrub, sandy riparian areas FebruaryMarchAprilMayJuneJulyAugustSeptember |
| California Saxifrage | Micranthes californica | Saxifragaceae | Saxifrage | Endemic, Uncommon, Perennial , typically blooms from February to April, Coastal Sage FebruaryMarchApril |
| California Thistle | Cirsium occidentale var. californ | Asteraceae | Sunflower | Endemic, Common, Perennial , typically blooms from April to August, Chaparral, Woodlands, Coastal Sage Scrub AprilMayJuneJulyAugust |
| California Walnut | Juglans californica | Juglandaceae | Walnut | Endemic, Common, Shrub or Tree , typically blooms from February to April, Oak Woodland FebruaryMarchApril |
| Canchalagua | Zeltnera venusta | Gentianaceae | Gentian | Native, Uncommon, Annual herb, typically blooms from May to August, open chaparral, coastal sage MayJuneJulyAugust |
| Canyon Dodder | Cuscuta subinclusa | Convolvulaceae | Morning Glory | Native, Common, Perennial Vine , typically blooms from March to October, Chaparral MarchAprilMayJuneJulyAugustSeptemberOctober |
| Canyon Sunflower | Venegasia carpesioides | Asteraceae | Sunflower | Native, Common, Shrub , typically blooms from December to July, shady places in Oak Woodland, Sage Scrub and Chaparral DecemberJanuaryFebruaryMarch |
| Castor Bean | Ricinis communis | Euphorbiaceae | Spurge | Invasive, Common, Shrub , typically blooms from January to December, Streambeds, roadsides, disturbed soil; JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
| Ceanothus | Ceanothus Species | Rhamnaceae | Buckthorn | Native, Common, Shrub , typically blooms from November to March, Chaparral, ridges, slopes, woodland, coastal scrub NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJulyAugust |
| Chalk Live-Forever | Dudleya pulverulenta | Crassulaceae | Stonecrop | Native, Common, Perennial , typically blooms from June to August, Rocky cliffsides in chaparral and coastal sage scrub JuneJulyAugust |
| Chamise | Adenostoma fasciculatum | Rosaceae | Rose | Native, Common, Shrub , typically blooms from February to September, dry slopes in Chaparral and Sage Scrub FebruaryMarchAprilMayJuneJulyAugustSeptember |
| Chaparral Currant | Ribes malvaceum | Grossulariaceae | Gooseberry | Native, Common, Perennial , typically blooms from December to April, Oak Woodland DecemberJanuaryFebruaryMarch |
| Chaparral Honeysuckle | Lonicera subspicata | Caprifoliaceae | Honeysuckle | Endemic, Common, Shrub , typically blooms from April to August, Chaparral AprilMayJuneJulyAugust |
| Checker Bloom | Sidalcea sparsifolia | Malvaceae | Mallow | Native, Uncommon, Perennial , typically blooms from March to July, Coastal Sage MarchAprilMayJuneJuly |
| Chia, Golden Chia | Salvia columbariae | Lamiaceae | Mint | Native, Common, Annual herb, typically blooms from March to June, Coastal Sage, Chaparral MarchAprilMayJune |
| Chinese Houses | Colinsia heterophylla | Plantaginaceae | Plantain | Native, Uncommon, Annual herb, typically blooms from February to May, Oak Woodland FebruaryMarchAprilMay |
| Chocolate Lily | Fritillaria biflora | Liliaceae | Lily | Endemic, Uncommon, Perennial , typically blooms from January to March, Heavy clay soil JanuaryFebruaryMarch |
| Cliff Aster | Malacothrix saxatilis | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from January to December, coastal sage/or chaparral JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
| Coast Cholla | Cylindropuntia prolifera | Cactaceae | Cactus | Native, Common, Shrub , typically blooms from April to June, dry slopes and grasslands at low elevations near the coast or in Sage Scrub AprilMayJune |
| Coastal Live Oak | Quercus agrifolia | Fagaceae | Beech | Native, Common, Tree , typically blooms from February to May, open woodlands FebruaryMarchAprilMay |
| Cobweb Thistle | Cirsium occidentale | Asteraceae | Sunflower | Native, Uncommon, Perennial , typically blooms from March to July, Coastal sage MarchAprilMayJuneJuly |
| Coffee Fern | Pellaea andromedifolia | Pteridaceae | Brake | Native, Common, Perennial , typically blooms from January to April, Chaparral and coastal sage scrub JanuaryFebruaryMarchApril |
| Collarless Poppy | Eschscholzia caespitosa | Papaveraceae | Poppy | Native, Common, Annual herb, typically blooms from March to July, Coastal Sage MarchAprilMayJuneJuly |
| Common Fiddleneck | Amsinckia intermedia | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from February to May, grassy hillsides, burned areas FebruaryMarchAprilMay |
| Common Sunflower | Helianthus annus | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from January to December, fields, roadsides and trailsides JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
| Common Vervain | Verbena lasiostachys | Verbenaceae | Vervain | Native, Common, Perennial , typically blooms from December to August, open areas, dry or moist DecemberJanuaryFebruaryMarch |
| Common Yarrow | Achillea millefolium | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from March to June, Chaparral MarchAprilMayJune |
| Cottonwood | Populus fremontii | Salicaceae | Willow | Native, Common, Tree , typically blooms from January to March, lower streambeds in riparian woodlands JanuaryFebruaryMarch |
| Coyote Brush | Baccharis pilularis | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to December, Sage Scrub, Oak Woodland, Chaparral and Grassland MayJuneJulyAugustSeptemberOctoberNovemberDecember |
| Cream Cups | Platystemon californicus | Papaveraceae | Poppy | Native, Uncommon, Annual herb, typically blooms from March to May, Open areas MarchAprilMay |
| Creek Monkey Flower | Erythranthe guttata | Phrymaceae | Lopseed | Native, Common, Annual herb, typically blooms from March to July, creeks, damp areas MarchAprilMayJuneJuly |
| Crimson Pitcher Sage | Salvia spathacea | Lamiaceae | Mint | Native, Common, Perennial , typically blooms from February to June, Lightly-shaded areas - Chaparral, Coastal Scrub FebruaryMarchAprilMayJune |
| Datura | Datura species | Solanaceae | Nightshade | Native, Common, Annual herb, typically blooms from March to November, full sun by roadsides, sandy or gravelly places MarchAprilMayJuneJulyAugustSeptemberOctoberNovember |
| Deerweed | Acmispon glaber | Fabaceae | Legume | Native, Common, Perennial , typically blooms from January to August, Chaparral JanuaryFebruaryMarchAprilMayJuneJulyAugust |
| Douglas Nightshade | Solanum douglasii | Solanaceae | Nightshade | Native, Common, Perennial , typically blooms from February to October, Shady hillsides, canyons, coastal scrubland FebruaryMarchAprilMayJuneJulyAugustSeptemberOctober |
| Downy Monkey Flower | Erythranthe pilosus | Phrymaceae | Lopseed | Native, Common, Annual herb, typically blooms from April to August, riparian AprilMayJuneJulyAugust |
| Eastwood Manzanita | Arctostaphylos glandulosa | Ericaceae | Heath | Native, Common, Shrub , typically blooms from November to February, Chaparral, rocky slopes and ridges NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptember |
| Elderberry | Sambucus nigra subsp. caerulea | Adoxaceae | Muskroot | Native, Common, Tree , typically blooms from April to August, woodlands, open areas and chaparral AprilMayJuneJulyAugust |
| Elegant Clarkia | Clarkia unguiculata | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from April to July, Sun or shade in grasslands, woodlands, and chaparral AprilMayJuneJuly |
| Eucrypta | Eucrypta chrysanthemifolia | Boraginaceae | Waterleaf | Native, Common, Annual herb, typically blooms from January to June, woodland, sage scrub, chaparral JanuaryFebruaryMarchAprilMayJune |
| Farewell-to-Spring | Clarkia bottae | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from April to July, Coastal Sage, open slopes AprilMayJuneJuly |
| Fern-Leaf Phacelia | Phacelia distans | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from March to June, dry slopes in Oak Woodland and Coastal Sage MarchAprilMayJune |
| Fiesta Flower | Pholistoma auritum | Boraginaceae | Waterleaf | Native, Common, Annual herb, typically blooms from March to May, shady areas, common throughout most plant communities MarchAprilMay |
| Fire Heart, Bleeding Heart | Ehrendorferia ochroleuca | Papaveraceae | Poppy | Native, Uncommon, Perennial , typically blooms from April to December, Chaparral, Oak Woodland AprilMayJuneJulyAugustSeptemberOctoberNovemberDecember |
| Fire Poppy | Papaver californicum | Papaveraceae | Poppy | Endemic, Uncommon, Annual herb, typically blooms from April to July, Chaparral AprilMayJuneJuly |
| Foothill Penstemon | Penstemon heterophyllus | Plantaginaceae | Plantain | Endemic, Uncommon, Perennial , typically blooms from April to July, dry hillsides in Oak Woodland and Chaparral AprilMayJuneJuly |
| Fringed Indian Pink | Silene laciniata | Caryophyllaceae | Pink | Native, Common, Perennial , typically blooms from April to July, shaded woodlands, sage scrub, chaparral AprilMayJuneJuly |
| Fringed Linanthus | Linanthus dianthiflorus | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from January to March, Coastal Sage, Chaparral JanuaryFebruaryMarch |
| Fuchsia-Flowered Gooseberry | Ribes speciosum | Grossulariaceae | Gooseberry | Native, Common, Shrub , typically blooms from January to May, shaded canyons in Sage Scrub and Chaparral JanuaryFebruaryMarchAprilMay |
| Giant Coreopsis | Coreopsis gigantea | Asteraceae | Sunflower | Endemic, Common, Perennial , typically blooms from November to June, Coastal areas, especially where fog is common NovemberDecemberJanuaryFebruaryMarchAprilMay |
| Globe Gilia | Gilia capitata | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from March to June, Chaparral MarchAprilMayJune |
| Globe Lily | Calochortus albus | Liliaceae | Lily | Native, Uncommon, Perennial , typically blooms from April to June, Oak Woodland AprilMayJune |
| Golden Currant | Ribes aureum | Grossulariaceae | Gooseberry | Native, Common, Shrub , typically blooms from January to March, stream beds, meadows JanuaryFebruaryMarch |
| Golden Star | Bloomeria crocea | Themidaceae | Brodiaea | Native, Common, Perennial , typically blooms from April to June, Coastal Sage, Chaparral AprilMayJune |
| Golden Yarrow | Eriophyllum confertiflorum | Asteraceae | Sunflower | Native, Common, Shrub , typically blooms from December to July, open places, dry slopes in Chaparral and Sage Scrub, rocky places at the base of cliffs DecemberJanuaryFebruaryMarch |
| Greenbark Ceanothus | Ceanothus spinosus | Rhamnaceae | Buckthorn | Native, Common, Shrub or Tree , typically blooms from February to April, Chaparral FebruaryMarchApril |
| Gum Plant | Grindelia camporum | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to September, open chaparral, coastal sage MayJuneJulyAugustSeptember |
| Hairy Leaved Ceanothus | Ceanothus oliganthus | Rhamnaceae | Buckthorn | Endemic, Common, Shrub or Tree , typically blooms from February to April, chaparral FebruaryMarchApril |
| Heart Leaved Penstemon | Keckiella cordifolia | Plantaginaceae | Plantain | Native, Common, Perennial , typically blooms from March to August, Coastal Sage, Oak Woodlands MarchAprilMayJuneJulyAugust |
| Hedge Nettle | Stachys bullata | Lamiaceae | Mint | Native, Common, Perennial , typically blooms from February to July, Chaparral, Woodlands, Sage Scrub FebruaryMarchAprilMayJuneJuly |
| Hillside Gooseberry | Ribes californicum | Grossulariaceae | Gooseberry | Endemic, Common, Shrub , typically blooms from January to March, woodland chapparal - northern slopes JanuaryFebruaryMarch |
| Hoary Leaved Ceanothus | Ceanothus crassifolius | Rhamnaceae | Buckthorn | Native, Common, Shrub or Tree , typically blooms from February to April, Chaparral FebruaryMarchApril |
| Holly Leaf Red Berry | Rhamnus ilicifolia | Rhamnaceae | Buckthorn | Native, Common, Shrub , typically blooms from February to April, coastal sage and chaparral FebruaryMarchApril |
| Holly-Leaved Cherry | Prunus ilicifolia | Rosaceae | Rose | Native, Common, Perennial Shrub , typically blooms from November to June, Chaparral, canyons, moist and/or north-facing NovemberDecemberJanuaryFebruaryMarchAprilMay |
| Humboldt Lily | Lilium humboldtii | Liliaceae | Lily | Native, Uncommon, Perennial , typically blooms from May to July, Chaparral and Oak Woodland, near streams MayJuneJuly |
| Indian Paintbrush | Castilleja affinis | Orobanchaceae | Broomrape | Native, Common, Perennial , typically blooms from February to May, Coastal Sage Scrub, Grassland, Chaparral FebruaryMarchAprilMay |
| Indian Warrior | Pedicularis densiflora | Orobanchaceae | Broomrape | Native, Uncommon, Perennial , typically blooms from February to April, Chaparral FebruaryMarchApril |
| Johnny-jump-up | Viola pedunculata | Violaceae | Violet | Native, Uncommon, Perennial , typically blooms from January to May, open grassy areas in woodlands, chaparral, sage scrub JanuaryFebruaryMarchAprilMay |
| Large-Flowered Phacelia | Phacelia grandiflora | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from January to June, woodlands, chaparral, coastal sage scrub JanuaryFebruaryMarchAprilMayJune |
| Leather Root | Hoita macrostachya | Fabaceae | Legume | Native, Uncommon, Perennial , typically blooms from June to September, Chaparral, wetland riparian JuneJulyAugustSeptember |
| Lemonade Berry | Rhus integrifolia | Anacardiaceae | Sumac | Native, Common, Shrub Tree , typically blooms from December to May, Chaparral, North Side DecemberJanuaryFebruaryMarch |
| Lupine | Lupinus Species | Fabaceae | Legume | Native, Common, Annual Perennial , typically blooms from February to June, Chaparral, ridges, slopes, canyons, coastal scrub FebruaryMarchAprilMayJune |
| Lyons Pentachaeta | Pentachaeta lyonii | Asteraceae | Sunflower | Endemic, Rare, Annual herb, typically blooms from May to August, Coastal Sage MayJuneJulyAugust |
| Mariposa Lily | Calochortus species | Liliaceae | Lily | Endemic, Common, Perennial , typically blooms from February to June, grasslands, slopes, chaparral FebruaryMarchAprilMayJune |
| Matilija Poppy | Romneya coulteri | Papaveraceae | Poppy | Endemic, Uncommon, Perennial , typically blooms from April to June, Coastal Sage Scrub AprilMayJune |
| Milkmaids | Cardamine californica | Brassicaceae | Mustard | Native, Uncommon, Perennial , typically blooms from January to March, Shady, moist hillsides or stream banks in riparian areas JanuaryFebruaryMarch |
| Milkwort | Polygala cornuta | Polygalacea | Milkwort | Native, Uncommon, Shrub , typically blooms from May to July, Riparian, Chaparral MayJuneJuly |
| Miners Lettuce | Claytonia perfoliata | Portulacaceae | Purslane | Native, Common, Annual herb, typically blooms from January to May, shady areas in chaparral, woodland, sage scrub JanuaryFebruaryMarchAprilMay |
| Morning Glory | Calystegia macrostegia | Convolvulaceae | Morning Glory | Native, Common, Perennial or Vine , typically blooms from March to August, Sage Scrub, Chaparral MarchAprilMayJuneJulyAugust |
| Mountain Mahogany | Cercocarpus betuloides | Rosaceae | Rose | Native, Common, Shrub , typically blooms from February to May, Chaparral FebruaryMarchAprilMay |
| Mugwort | Artemisia douglasiana | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from July to November, Riparian Woodlands JulyAugustSeptemberOctoberNovember |
| Mule Fat | Baccharis salicifolia | Asteraceae | Sunflower | Native, Common, Shrub , typically blooms from January to December, Riparian JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
| Mustard Evening Primrose | Eulobus californicus | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from March to May, Grassland, Chaparral, Coastal Sage Scrub, often on dry slopes MarchAprilMay |
| Narrow Leaved Milkweed | Asclepias fascicularis | Apocynaceae | Dogbane | Endemic, Common, Perennial , typically blooms from May to September, Grasslands MayJuneJulyAugustSeptember |
| Notable Penstemon | Penstemon spectabilis | Plantaginaceae | Plantain | Native, Common, Perennial , typically blooms from April to June, Sage Chaparral AprilMayJune |
| Owl’s Clover | Castilleja exserta | Orobanchaceae | Broomrape | Native, Common, Annual herb, typically blooms from January to June, Grasslands and Coastal Sage Scrub JanuaryFebruaryMarchAprilMayJune |
| Parry’s Phacelia | Phacelia parryi | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from March to May, Chaparral, Coastal Sage Scrub MarchAprilMay |
| Peak Rush Rose | Crocanthemum scoparium | Cistaceae | Rock Rose | Native, Common, Shrub , typically blooms from March to July, Chaparral and coastal sage scrub MarchAprilMayJuneJuly |
| Peninsular Onion | Allium peninsulare | Alliaceae | Onion | Native, Uncommon, Perennial , typically blooms from April to May, Coastal Sage AprilMay |
| Perezia, Sacapellote | Acourtia microcephala | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to July, Woodland and or Chaparral MayJuneJuly |
| Pin Cushion | Chaenactis artemisiifolia | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from March to June, coastal scrub and chaparral MarchAprilMayJune |
| Pitcher Sage | Lepechinia fragrans | Lamiaceae | Mint | Native, Common, Shrub , typically blooms from April to July, Chaparral AprilMayJuneJuly |
| Poison Oak | Toxicodendron diversilobum | Anacardiaceae | Sumac | Native, Common, Perennial Vine , typically blooms from February to June, oak woodland FebruaryMarchAprilMayJune |
| Prickly Pear | Opuntia oricola | Cactaceae | Cactus | Native, Common, Perennial , typically blooms from May to August, low elevation chaparral and coastal sage scrub MayJuneJulyAugust |
| Prickly Phlox | Linanthus californicus | Polemoniaceae | Phlox | Native, Common, Perennial , typically blooms from March to June, Chaparral MarchAprilMayJune |
| Prickly Popcorn Flower | Cryptantha muricata | Boraginaceae | Borage | Native, Common, Annual herb, typically blooms from January to June, open areas on rocky slopes JanuaryFebruaryMarchAprilMayJune |
| Prickly Poppy | Argemone munita | Papaveraceae | Poppy | Native, Uncommon, Perennial Annual , typically blooms from April to July, dry, sandy soil or gravel AprilMayJuneJuly |
| Purple Nightshade | Solanum xanti | Solanaceae | Nightshade | Native, Common, Shrub , typically blooms from December to June, Sage, chapparal DecemberJanuaryFebruaryMarch |
| Purple Sage | Salvia leucophylla | Lamiaceae | Mint | Native, Common, Shrub , typically blooms from February to August, Coastal Sage FebruaryMarchAprilMayJuneJulyAugust |
| Rattlesnake Weed | Euphorbia albomarginata | Euphorbiaceae | Spurge | Native, Common, Perennial , typically blooms from April to November, dry slopes and fields AprilMayJuneJulyAugustSeptemberOctoberNovember |
| Red Maids | Calandrinia menziesii | Portulacaceae | Purslane | Native, Uncommon, Annual herb, typically blooms from February to June, grassy areas and woodland edges FebruaryMarchAprilMayJune |
| Red Shank | Adenostoma sparsifolium | Rosaceae | Rose | Native, Uncommon, Shrub or Tree , typically blooms from June to September, dry slopes in rain shadow of coastal slopes JuneJulyAugustSeptember |
| Red Skinned Onion | Allium haematochiton | Alliaceae | Onion | Native, Common, Perennial , typically blooms from March to May, hillsides near water MarchAprilMay |
| Red-Stem Filaree | Erodium cicutarium | Geraniaceae | Geranium | Invasive, Common, Annual herb, typically blooms from November to June, open or grassy areas in dry, disturbed and/or sand NovemberDecemberJanuaryFebruaryMarchAprilMay |
| Rock Daisy | Perityle emoryi | Asteraceae | Sunflower | Native, Uncommon, Annual herb, typically blooms from March to October, Coastal Sage MarchAprilMayJuneJulyAugustSeptemberOctober |
| Rose Snapdragon | Antirrhinum multiflorum | Plantaginaceae | Plantain | Endemic, Uncommon, Annual herb, typically blooms from May to July, Chaparal MayJuneJuly |
| Royal Goldfields | Lasthenia coronaria | Asteraceae | Sunflower | Native, Uncommon, Annual herb, typically blooms from March to May, open areas, hillsides MarchAprilMay |
| Sagebrush | Artemisia californica | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from September to December, Coastal Sage SeptemberOctoberNovemberDecember |
| San Diego Milk-aster | Stephanomeria diegensis | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from July to December, Chaparral, Coastal Scrub JulyAugustSeptemberOctoberNovemberDecember |
| Sand Verbena | Abronia maritima | Nyctaginaceae | Four O'Clock | Native, Common, Perennial , typically blooms from February to October, coastal dunes FebruaryMarchAprilMayJuneJulyAugustSeptemberOctober |
| Sawtooth Goldenbush | Hazardia squarrosa | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from June to October, Chaparral, Coastal Sage Scrub JuneJulyAugustSeptemberOctober |
| Scale Broom | Lepidospartum squamatum | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from August to November, Chaparral, Coastal Sage Scrub AugustSeptemberOctoberNovember |
| Scarlet Bugler | Penstemon centranthifolius | Plantaginaceae | Plantain | Native, Common, Perennial , typically blooms from February to June, Sage Chaparral Oak Woodland FebruaryMarchAprilMayJune |
| Scarlet Larkspur | Delphinium cardinale | Ranunculaceae | Buttercup | Native, Common, Perennial , typically blooms from May to August, chaparral and sage scrub MayJuneJulyAugust |
| Scarlet Monkey Flower | Erythranthe cardinalis | Phrymaceae | Lopseed | Native, Common, Perennial , typically blooms from May to September, wet areas along creeks, seeps MayJuneJulyAugustSeptember |
| Scrub Oak | Quercus berberidifolia | Fagaceae | Beech | Native, Common, Shrub or Tree , typically blooms from March to May, Coastal Sage MarchAprilMay |
| Shooting Star | Primula clevelandii | Primulaceae | Primrose | Native, Common, Perennial , typically blooms from December to March, Open grassy areas DecemberJanuaryFebruaryMarch |
| Skull Caps | Scutellaria tuberosa | Lamiaceae | Mint | Native, Uncommon, Perennial , typically blooms from February to May, Chaparral FebruaryMarchAprilMay |
| Slender Sunflower | Helianthus gracilentus | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from May to October, Chaparral, fields, dry slopes, roadsides MayJuneJulyAugustSeptemberOctober |
| Slender Tarweed | Deinandra fasciculata | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from May to August, Grasslands, Chaparral MayJuneJulyAugust |
| Slimy Monkey Flower | Erythranthe floribunda | Phrymaceae | Lopseed | Native, Common, Annual herb, typically blooms from May to September, Riparian MayJuneJulyAugustSeptember |
| Snowberry | Symphoricarpos mollis | Caprifoliaceae | Honeysuckle | Native, Common, Perennial , typically blooms from March to May, Chaparral MarchAprilMay |
| Soap Plant | Chlorogalum pomeridianum | Agavaceae | Agave | Native, Common, Perennial , typically blooms from May to June, coastal sage, dry grassland MayJune |
| Southern Tauschia | Tauschia arguta | Apiaceae | Carrot | Native, Common, Perennial , typically blooms from February to June, dry slopes in Sage Scrub, Woodlands and Chaparral FebruaryMarchAprilMayJune |
| Speckled Clarkia | Clarkia cylindrica | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from April to July, Chaparral, slopes, coastal sage, woodlands, grassl AprilMayJuneJuly |
| Star Lily | Toxicoscordion fremontii | Melanthiaceae | Deathcamasus | Native, Uncommon, Perennial , typically blooms from February to June, Coastal Sage FebruaryMarchAprilMayJune |
| Stick Leaf, San Luis Blazingstar | Mentzelia micrantha | Loasaceae | Loasaceae | Native, Uncommon, Annual herb, typically blooms from March to June, Coastal Sage MarchAprilMayJune |
| Sticky Cinquefoil | Drymocallis glandulosa | Rosaceae | Rose | Native, Uncommon, Perennial , typically blooms from April to July, Oak Woodland AprilMayJuneJuly |
| Sticky Gilia, Stinky Gilia | Allophylum glutinosum | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from February to August, Coastal Sage FebruaryMarchAprilMayJuneJulyAugust |
| Sticky Monkey Flower | Diplacus longiflorus | Phrymaceae | Lopseed | Native, Common, Perennial , typically blooms from March to August, Chaparral MarchAprilMayJuneJulyAugust |
| Sticky Phacelia | Phacelia viscida | Boraginaceae | Borage | Native, Uncommon, Annual , typically blooms from March to June, Coastal sage scrub and chaparral MarchAprilMayJune |
| Stream Orchid | Epipactis gigantea | Orchidaceae | Orchid | Native, Uncommon, Perennial , typically blooms from April to July, Riparian AprilMayJuneJuly |
| Sugar Bush | Rhus ovata | Anacardiaceae | Sumac | Native, Common, Shrub , typically blooms from March to June, Chaparral - South facing slopes MarchAprilMayJune |
| Sumac | Malosma laurina | Anacardiaceae | Sumac | Native, Common, Perennial , typically blooms from June to August, Chaparral JuneJulyAugust |
| Sycamore | Platanus racemosa | Platanaceae | Sycamore | Native, Common, Tree , typically blooms from February to April, stream beds FebruaryMarchApril |
| Tejon Milk-Aster | Stephanomeria cichoriacea | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from July to October, Chaparral, Coastal Sage JulyAugustSeptemberOctober |
| Telegraph Weed | Heterotheca grandiflora | Asteraceae | Sunflower | Native, Common, Annual herb, typically blooms from January to December, sand, disturbed soils JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
| Tidy Tips | Layia platyglossa | Asteraceae | Sunflower | Native, Uncommon, Annual , typically blooms from March to June, grasslands MarchAprilMayJune |
| Toyon | Heteromeles arbutifolia | Rosaceae | Rose | Native, Common, Shrub Tree , typically blooms from May to July, Chaparral, ridges, slopes, woodland, coastal scrub MayJuneJuly |
| Tree Tobacco | Nicotiana glauca | Solanaceae | Nightshade | Invasive, Common, Shrub Tree , typically blooms from January to December, streambeds and disturbed soils JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecemberAlways |
| Turkey Mullein | Croton setiger | Euphorbiaceae | Spurge | Native, Common, Annual herb, typically blooms from April to November, Common in open, sandy disturbed places AprilMayJuneJulyAugustSeptemberOctoberNovember |
| Turkish Rugging | Chorizanthe staticoides | Polygonaceae | Buckwheat | Native, Common, Annual herb, typically blooms from April to July, grassy slopes, dry and sandy places in Chaparral AprilMayJuneJuly |
| Twining Snapdragon | Antirrhinum kelloggii | Plantaginaceae | Plantain | Native, Common, Annual or Vine herb, typically blooms from January to May, Coastal Sage Scrub and dry areas in the Chaparral JanuaryFebruaryMarchAprilMay |
| Two Tone Everlasting | Pseudognaphalium biolettii | Asteraceae | Sunflower | Native, Common, Perennial , typically blooms from January to May, coastal scrub and chaparral JanuaryFebruaryMarchAprilMay |
| Valley Oak | Quercus lobata | Fagaceae | Beech | Native, Common, Tree , typically blooms from March to May, open woodlands, riparian forests, valley savannas MarchAprilMay |
| Variable Linanthus | Leptosiphon parviflorus | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from March to May, Coastal Sage MarchAprilMay |
| Vinegar Weed | Trichostema lanceolatum | Lamiaceae | Mint | Native, Common, Annual herb, typically blooms from June to November, dry, sunny fields or low hills
JuneJulyAugustSeptemberOctoberNovember |
| Violet Snapdragon | Antirrhinum nuttallianum | Plantaginaceae | Plantain | Native, Uncommon, Annual herb, typically blooms from March to June, Grassy slopes and canyons MarchAprilMayJune |
| Virgin's Bower | Clematis lasiantha | Ranunculaceae | Buttercup | Endemic, Common, Perennial Vine , typically blooms from January to May, Canyons and Chaparral, open places in Woodlands JanuaryFebruaryMarchAprilMay |
| Wand Buckwheat | Eriogonum elongatum | Polygonaceae | Buckwheat | Native, Common, Perennial , typically blooms from July to November, coastal scrub and chaparral JulyAugustSeptemberOctoberNovember |
| Western Virgins Bower | Clematis ligusticifolia | Ranunculaceae | Buttercup | Native, Common, Perennial Vine , typically blooms from June to September, riparian JuneJulyAugustSeptember |
| Western Wallflower | Erysimum capitatum | Brassicaceae | Mustard | Native, Common, Perennial , typically blooms from January to June, Openings in Chaparral JanuaryFebruaryMarchAprilMayJune |
| Whispering Bells | Emmenanthe penduliflora | Boraginaceae | Borage | Native, Uncommon, Annual herb, typically blooms from February to June, Chaparral, Coastal Sage FebruaryMarchAprilMayJune |
| White Chaparral Currant | Ribes indecorum | Grossulariaceae | Gooseberry | Native, Common, Perennial , typically blooms from November to February, coastal scrub and chaparral NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptember |
| White Hedge Nettle | Stachys albens | Lamiaceae | Mint | Endemic, Common, Perennial , typically blooms from May to September, Grassands Coastal Sage MayJuneJulyAugustSeptember |
| White Sage | Salvia apiana | Lamiaceae | Mint | Native, Common, Shrub , typically blooms from April to July, Coastal Sage AprilMayJuneJuly |
| White Snapdragon | Antirrhinum coulterianum | Plantaginaceae | Plantain | Native, Uncommon, Annual herb, typically blooms from April to July, Sage, Chapparal AprilMayJuneJuly |
| Wild Cucumber | Marah macrocarpus | Cucurbitaceae | Gourd | Native, Common, Perennial Vine herb vine, typically blooms from November to April, woodlands, chaparral, coastal sage scrub NovemberDecemberJanuaryFebruaryMarchAprilMayJuneJuly |
| Wild Heliotrope | Heliotropium curassavicum | Boraginaceae | Borage | Native, Common, Perennial , typically blooms from April to November, Moist to Dry Saline Soils AprilMayJuneJulyAugustSeptemberOctoberNovember |
| Wild Peony | Paeonia californica | Paeoniaceae | Peony | Endemic, Common, Perennial , typically blooms from December to May, Chaparral, meadows & ridges DecemberJanuaryFebruaryMarch |
| Wild Rose | Rosa californica | Rosaceae | Rose | Native, Common, Shrub , typically blooms from March to September, moist places in many plant communities MarchAprilMayJuneJulyAugustSeptember |
| Wild Sweet Pea | Lathyrus vestitus | Fabaceae | Legume | Native, Common, Perennial Vine , typically blooms from March to August, Chaparral, Oak Woodlands MarchAprilMayJuneJulyAugust |
| Wild radish | Raphanus sativus | Brassicaceae | Mustard | Invasive, Common, Annual herb, typically blooms from December to May, fields, meadows, disturbed places DecemberJanuaryFebruaryMarch |
| Willow Herb Clarkia | Clarkia epilobioides | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from April to May, Oak Woodland AprilMay |
| Wind Poppy | Papaver heterophyllum | Papaveraceae | Poppy | Native, Uncommon, Annual herb, typically blooms from April to May, Chaparral, grassy areas AprilMay |
| Wine Cup Clarkia | Clarkia purpurea | Onagraceae | Evening Primrose | Native, Common, Annual herb, typically blooms from March to June, Grassy Openings MarchAprilMayJune |
| Wishbone Bush | Mirabilis laevis | Nyctaginaceae | Four O'Clock | Native, Common, Perennial , typically blooms from November to May, Chaparral and Coastal Sage Scrub NovemberDecemberJanuaryFebruaryMarchAprilMayJune |
| Woodland Star | Lithopragma affine | Saxifragaceae | Saxifrage | Native, Common, Perennial , typically blooms from March to May, Grasslands, mountains MarchAprilMay |
| Woolly Blue Curls | Trichostema lanatum | Lamiaceae | Mint | Native, Common, Perennial , typically blooms from February to June, chaparral, coastal sage scrub FebruaryMarchAprilMayJune |
| Wooly Sapphire | Eriastrum sapphirinum | Polemoniaceae | Phlox | Native, Uncommon, Annual herb, typically blooms from April to July, Chaparral AprilMayJuneJuly |
| Yellow Monkey Flower | Diplacus brevipes | Phrymaceae | Lopseed | Native, Common, Annual herb, typically blooms from April to July, Open Chaparral AprilMayJuneJuly |
| Yellow Throated Phacelia | Phacelia brachyloba | Boraginaceae | Borage | Native, Uncommon, Annual , typically blooms from March to June, coastal sage scrub and chaparral MarchAprilMayJune |
| Yerba Mansa | Anemopsis californica | Saururaceae | Lizard Tail | Native, Uncommon, Perennial , typically blooms from March to July, Moist soils MarchAprilMayJuneJuly |
| Yerba Santa | Eriodichtyon crassifolium | Boraginaceae | Waterleaf | Native, Common, Shrub , typically blooms from January to June, Sandy, rocky areas in chaparral and sage scrub JanuaryFebruaryMarchAprilMayJune |
| Yucca | Hesperoyucca whipplei | Agavaceae | Agave | Native, Common, Perennial , typically blooms from April to June, chaparral or coastal sage scrub
AprilMayJune |