Gambelia (Galvezia) juncea 'Grand Canon' Grand Canon Bush Snapdragon (Horticultural)
Gambelia (Galvezia) juncea 'Punta Banda' Punta Banda Bush Snapdragon (Horticultural)
Gambelia (Galvezia) speciosa Island Bush Snapdragon (Southern)
Gambelia (Galvezia) speciosa ‘Firecracker’ Firecracker Island Bush Snapdragon (Horticultural)
Garrya elliptica Coast Tassel Bush (Northern, Central)
Garrya elliptica 'Evie' Evie Silktassel (Horticultural)
Garrya elliptica 'James Roof' James Roof Silktassel (Horticultural)
Gilia capitata Globe Gilia (Statewide)
Gilia tricolor Tricolored Gilia (Southern, Northern)
Grindelia camporum Great Valley Gumplant (Southern, Central)
Grindelia camporum var. bracteosa Rayless Gumplant (Southern, Central, Baja California)
Grindelia stricta var. platyphylla Coast Gumplant (Central, Channel Islands, Northern)
Grindelia stricta var. venulosa Coast Gumplant (Central, Channel Islands, Northern)
Gutierrezia californica California Matchweed (Southern, Central, Baja California)
Gutierrezia sarothrae Matchweed, Snakeweed (Southern, Central)
Hazardia cana San Clemente Island Hazardia (San Clemente Island & Guadalupe Island)
Hazardia detonsa Island Bristleweed (Channel Islands)
Hazardia squarrosa Sawtooth Goldenbush (Southern, Central, Baja California)
Helianthemum scoparium Peak Rush-Rose (Statewide)
Helianthus gracilentus Slender Sunflower (Statewide, Baja)
Heliotropium curassavicum Salt Heliotrope (Statewide)
Hesperoyucca whipplei Chaparral Candle (Southern, Baja California)
Heteromeles arbutifolia Toyon (Statewide)
Heuchera 'Canyon Duet' Canyon Duet Coral Bells (Hybrid)
Heuchera 'Canyon Pink' Canyon Pink Coral Bells (Hybrid)
Heuchera hirsutissima 'Santa Rosa' Santa Rosa Coral Bells (Horticultural selection from Santa Rosa Island)
Heuchera maxima Island Alum Root (Southern, Islands)
Holodiscus discolor Oceanspray (Pacific Northwest to Los Angeles area)
Hosackia crassifolius Buck Lotus (San Diego-Otay Mountain)
Hyptis emoryi 'Silver Lining' Silver Lining Desert Lavender (Horticultural)
Iris douglasiana Douglas Iris (Northern, Central)
Iris 'Canyon Snow' Canyon Snow Iris (Horticultural)
Iris 'Pacific Coast' Pacific Coast Iris (Hybrid)
Isocoma menziesii Goldenbush (Statewide)
Isomeris (Peritoma) arborea Bladderpod (Southern)
Iva hayesiana San Diego Marsh-Elder (Southern)