O'Conner's legumeTrifolium fragiferum O'Connor (revegetation use)Ground cover- NCL
- CVL
- SCL
- SIL
- HD×
- LD×
Plants starting with O: water needs by California climate zone
Each plant shows its water use rating for each of the six California climate zones. Minutes opens the sprinkler calculator with the plant and a climate city preset.
O'Conner's legumeTrifolium fragiferum O'Connor (revegetation use)Ground cover
O'Connor's legumeTrifolium fragiferum O'Connor (landscape use)Ground cover- NCM
- CVM
- SCM
- SIM
- HD×
- LD×
oak of TaborQuercus ithaburensisTree- NC?
- CVL
- SC?
- SI?
- HD?
- LD?
oakleaf hydrangeaHydrangea quercifoliaShrub- NCM
- CVM
- SCM
- SIM
- HD×
- LD×
obedient plantPhysostegia virginianaPerennial- NCM
- CVH
- SCM
- SIM
- HD?
- LD?
Ocahui Century PlantAgave ocahuiSucculent- NCVL
- CVVL
- SCL
- SIVL
- HDVL
- LDVL
ocotilloFouquieria splendensShrub, Succulent, California native- NC×
- CV×
- SCVL
- SIVL
- HDVL
- LDVL
Octopus AgaveAgave vilmoriniana- NCVL
- CVVL
- SCL
- SIVL
- HDVL
- LDVL
Okame-Zaza bambooShibataea kumasasaGround cover, Shrub, Bamboo- NCM
- CV?
- SCM
- SI?
- HD?
- LD?
Okinawan hollyIlex dimorphophyllaShrub- NCM
- CVM
- SCM
- SIM
- HD×
- LD?
Oklahoma RedbudCercis reniformis texensis 'Oklahoma'Tree- NCL
- CVL
- SCL
- SIL
- HDM
- LDM
old man cactusCephalocereus spp.Shrub- NCVL
- CV×
- SCVL
- SIL
- HDL
- LDL
Old Man of the AndesOreocereus spp. & cvs.- NCVL
- CV?
- SC?
- SIVL
- HD?
- LD?
old man of the mountainTetraneuris grandifloraPerennial- NCL
- CV?
- SC?
- SI?
- HD?
- LD?
oleanderNerium oleander ssp. & cvs.Shrub- NCL
- CVVL
- SCL
- SIL
- HDM
- LDM
oliveOlea europaea ssp. & cvs.Tree, Shrub- NCL
- CVL
- SCL
- SIL
- HDL
- LDL
- NC?
- CVL
- SCL
- SI?
- HD?
- LD?
olympic hypericumHypericum olympicumShrub- NCL
- CV?
- SC?
- SI?
- HD×
- LD×
omeo gumEucalyptus neglectaTree- NCL
- CV?
- SCL
- SI?
- HD?
- LD?
oniongrassMelica californicaOrnamental grass, California native- NC?
- CVVL
- SCL
- SI?
- HD?
- LD?
oracle oakQuercus x morehusTree, California native- NCVL
- CV?
- SC?
- SIL
- HD?
- LD?
orange bellsTecoma x smithiiShrub- NCL
- CV?
- SCM
- SIL
- HD?
- LD?
orange cestrumCestrum auranticumShrub, Vine- NCM
- CVM
- SCM
- SIM
- HD?
- LD?
orange clock vineThunbergia gregoriiVine- NCM
- CV×
- SCM
- SIM
- HD×
- LDM
orange flame vineCombretum fruticosumVine- NC×
- CV×
- SCM
- SIM
- HD×
- LD×
Orange GumEucalyptus pravaTree- NCL
- CV?
- SC?
- SI?
- HD?
- LD?
orange honeysuckleLonicera ciliosaVine, California native- NCM
- CV?
- SC?
- SIM
- HD?
- LD?
orange jessamineMurraya exoticaShrub- NC×
- CV×
- SCM
- SIM
- HD?
- LDM
orange jessamineMurraya paniculataShrub- NC?
- CV×
- SCM
- SIM
- HD×
- LDM
Orange Jubilee tecomaTecoma fulva spp. guarume (Tecoma "Orange Jubilee")Shrub- NCM
- CVM
- SCL
- SIL
- HDM
- LDM
orange lechenaultiaLechenaultia formosa orangeShrub- NCL
- CV?
- SCL
- SIM
- HD?
- LD?
orange milkweedAsclepias tuberosaPerennial- NCM
- CVM
- SCM
- SIM
- HDM
- LDM
orange New Zealand sedgeCarex testaceaPerennial- NCM
- CVM
- SCM
- SIM
- HD?
- LD?
orange peel cestrumCestrum x 'Orange Peel'Shrub- NCM
- CV?
- SCM
- SI?
- HD?
- LDM
orange puffsKleinia amaniensis (Senecio amaniensis)Perennial, Succulent- NC?
- CV?
- SCL
- SI?
- HD?
- LD?
orange sneezeweedHymenoxys hoopesii (Helenium hoopesii)Perennial, California native- NCM
- CV?
- SC?
- SIH
- HD?
- LD?
orange thornCitriobatus spinescensShrub- NC×
- CV?
- SCM
- SI?
- HD?
- LD?
Orange Trumpet BushTecoma 'Sun Trumpets Orange'Shrub- NCL
- CVL
- SCL
- SIL
- HD?
- LDM
Orange Vanilla Popsicle Dwarf PokerKniphofia 'Orange Vanilla Popsicle' PP24292Perennial- NCL
- CVM
- SCM
- SIM
- HDM
- LD?
orange, lemon etc.Citrus spp.Tree- NCM
- CVM
- SCM
- SIM
- HD×
- LDM
Oregon ashFraxinus latifoliaTree, California native- NCM
- CVM
- SCM
- SI×
- HD×
- LD×
Oregon fleabaneErigeron speciosusPerennial- NCM
- CV?
- SC?
- SIM
- HD?
- LD?
Oregon grapeBerberis aquifolium (Mahonia)Shrub, California native- NCL
- CVL
- SCL
- SIL
- HDL
- LDM
Oregon Mist ceanothusCeanothus thyrsiflorus 'Oregon Mist'Shrub, California native- NCL
- CV?
- SC?
- SI?
- HD×
- LD×
Oregon white oakQuercus garryanaTree, California native- NCL
- CVL
- SCL
- SI×
- HD?
- LD?
organ pipe cactusStenocereus thurberi (Lemaireocereus thurberi)Shrub, Succulent- NC×
- CV×
- SCVL
- SIL
- HD×
- LDVL
oriental arborvitaePlatycladus orientalis (Thuja orientalis)Shrub- NCM
- CVM
- SCM
- SIM
- HD?
- LDM
oriental bush cherryPrunus japonicaShrub, Tree- NC?
- CVM
- SC?
- SI?
- HD?
- LD?
oriental chain fernWoodwardia orientalisPerennial- NC?
- CV?
- SCH
- SIH
- HD×
- LD×
oriental gold giant reedArundo formosana 'Oriental Gold'Ornamental grass- NCH
- CV?
- SCM
- SIM
- HD?
- LD?
oriental ostrich fernMatteuccia orientalisPerennial- NC?
- CV?
- SC?
- SI?
- HD?
- LD?
Oriental Pearl Indian hawthornRhaphiolepis indica 'Parhap' Oriental PearlShrub- NC?
- CVL
- SCL
- SI?
- HD?
- LD?
oriental poppyPapaver orientalePerennial- NCM
- CVM
- SCM
- SIM
- HD×
- LD×
oriental sprucePicea orientalisTree- NC?
- CV?
- SC?
- SI×
- HD?
- LD×
origanilloAloysia wrightiiShrub, California native- NC?
- CV?
- SCL
- SI?
- HD?
- LD?
ornamental rhubarbRheum palmatum var. tanguticumPerennial- NCM
- CVH
- SC?
- SI?
- HD?
- LD?
ornithogalumOrnithogalum regale (Galtonia regalis)Bulb- NC?
- CV?
- SCL
- SI?
- HD?
- LD?
oronoAzara dentataTree- NCM
- CV×
- SCM
- SI?
- HD×
- LD×
orthrosantusOrthrosanthus var. chimboracensis centroamericanus now O. monadelphusPerennial- NCL
- CV?
- SCM
- SI?
- HD?
- LD?
Oso Easy Double Pink roseRosa Oso Easy® Double PinkGround cover, Shrub- NC?
- CVL
- SCL
- SI?
- HD?
- LD?
Oso Easy Urban Legend roseRosa Oso Easy® Urban Legend®Shrub- NC?
- CVL
- SC?
- SI?
- HD?
- LD?
osoberryOemleria cerasiformisShrub, California native- NCM
- CV?
- SCL
- SIL
- HD?
- LD?
ostrich fernMatteuccia struthiopterisPerennial- NCM
- CVM
- SCM
- SIH
- HD?
- LD?
Otay manzanitaArctostaphylos otayensisShrub, California native- NC?
- CV?
- SCVL
- SIVL
- HD×
- LD×
Otay Mountain lotusHosackia crassifolia var. otayensis (Lotus crassifolius var. otayensis)Perennial, California native- NCL
- CVM
- SCVL
- SIL
- HD?
- LD?
otter bushGomphostigma virgatumPerennial- NCL
- CV?
- SCM
- SI?
- HD?
- LD?
otterbossieGossypium harknessiiShrub- NC?
- CV?
- SC?
- SI?
- HD?
- LDL
Outback Senna, Outback CassiaSenna oliogophyllaShrub- NCL
- CV?
- SC?
- SIL
- HDL
- LDL
ovens wattleAcacia pravissimaTree- NCL
- CVL
- SCL
- SI?
- HD?
- LD?
Owlswood Blue CeanothusCeanothus 'Owlswood Blue'Shrub, California native- NCL
- CVL
- SCL
- SIL
- HD×
- LD×
oxbaneBoophone distichaBulb- NC?
- CV?
- SCL
- SI?
- HD?
- LD?
oyama magnoliaMagnolia sieboldiiShrub, Tree- NCM
- CVM
- SCM
- SI?
- HD?
- LD?
Photo credits, 71 images from Wikimedia Commons
- O'Conner's legume: Christian Fischer, CC BY-SA 3.0 (licence)
- O'Connor's legume: Christian Fischer, CC BY-SA 3.0 (licence)
- oak of Tabor: Offer.s.z, CC BY-SA 4.0 (licence)
- oakleaf hydrangea: Eric in SF, CC BY-SA 3.0 (licence)
- obedient plant: LinBow, CC BY-SA 2.0 (licence)
- Ocahui Century Plant: Stan Shebs, CC BY-SA 3.0 (licence)
- ocotillo: Ricraider at English Wikipedia, Public domain
- Octopus Agave: Stan Shebs, CC BY-SA 3.0 (licence)
- Okame-Zaza bamboo: KENPEI, CC BY-SA 3.0 (licence)
- Okinawan holly: Daderot, CC0 (licence)
- Oklahoma Redbud: Famartin, CC BY-SA 4.0 (licence)
- old man cactus: Rosario, CC BY 4.0 (licence)
- Old Man of the Andes: Stan Shebs, CC BY-SA 3.0 (licence)
- old man of the mountain: Stan Shebs, CC BY-SA 3.0 (licence)
- oleander: Alvesgaspar, CC BY 2.5 (licence)
- olive: Hans Hillewaert, CC BY-SA 3.0 (licence)
- olympic hypericum: Karelj, Public domain
- omeo gum: Ian Brooker and David Kleinig, CC BY 3.0 au (licence)
- oniongrass: Robert Steers/NPS, CC0 (licence)
- oracle oak: Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0 (licence)
- orange bells: Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0 (licence)
- orange cestrum: Kurt Stüber, CC BY-SA 3.0 (licence)
- orange clock vine: Jon Sullivan, Public domain
- orange flame vine: Noel Leindekar, CC BY 3.0 (licence)
- Orange Gum: Jayn Hobba, CC BY 3.0 au (licence)
- orange honeysuckle: Walter Siegmund, CC BY 2.5 (licence)
- orange jessamine: KENPEI, CC BY-SA 3.0 (licence)
- orange jessamine: Forest & Kim Starr, CC BY 3.0 (licence)
- Orange Jubilee tecoma: anniesannuals, CC BY 2.0 (licence)
- orange lechenaultia: Melburnian, CC BY-SA 3.0 (licence)
- orange milkweed: Ragesoss, CC BY-SA 3.0 (licence)
- orange New Zealand sedge: UC Davis Arboretum and Public Garden, CC BY 2.0 (licence)
- orange peel cestrum: Photo by David J. Stang, CC BY-SA 4.0 (licence)
- orange puffs: Pieter Pelser, CC BY 3.0 (licence)
- orange sneezeweed: JerryFriedman, CC BY-SA 3.0 (licence)
- orange thorn: Raffi Kojian, CC BY-SA 3.0 (licence)
- Orange Trumpet Bush: Enziee, CC BY-SA 4.0 (licence)
- Orange Vanilla Popsicle Dwarf Poker: Varsenik Danielyan, CC BY-SA 4.0 (licence)
- orange, lemon etc.: Ellen Levy Finch (Elf), CC BY-SA 3.0 (licence)
- Oregon ash: Jean-Pol GRANDMONT, CC BY 3.0 (licence)
- Oregon fleabane: Kor!An (Андрей Корзун), CC BY-SA 3.0 (licence)
- Oregon grape: Ellyne Geurts, CC0 (licence)
- Oregon Mist ceanothus: Aethonatic, CC0 (licence)
- Oregon white oak: David Stanley from Nanaimo, Canada, CC BY 2.0 (licence)
- organ pipe cactus: The original uploader was Pretzelpaws at English Wikipedia., CC BY-SA 3.0 (licence)
- oriental arborvitae: yeowatzup at Flickr, CC BY 2.0 (licence)
- oriental bush cherry: Vincent Ignace, CC BY-SA 3.0 (licence)
- oriental chain fern: Kor!An (Корзун Андрей), CC BY-SA 3.0 (licence)
- oriental gold giant reed: Shih-Shiuan Kao, CC BY-SA 2.0 (licence)
- oriental ostrich fern: Daderot, CC0 (licence)
- Oriental Pearl Indian hawthorn: Dave Whitinger, CC BY-SA 3.0 (licence)
- oriental poppy: Paolobon140, CC BY-SA 3.0 (licence)
- oriental spruce: Karduelis, Public domain
- origanillo: Stan Shebs, CC BY-SA 3.0 (licence)
- ornamental rhubarb: H. Zell, CC BY-SA 3.0 (licence)
- ornithogalum: Onderwijsgek, CC BY-SA 2.5 nl (licence)
- orono: Burkhard Mücke, CC BY-SA 3.0 (licence)
- orthrosantus: Gnangarra, CC BY 3.0 au (licence)
- Oso Easy Double Pink rose: Laitche, CC BY 3.0 (licence)
- Oso Easy Urban Legend rose: Captain-tucker, CC BY-SA 4.0 (licence)
- osoberry: Walter Siegmund, CC BY 2.5 (licence)
- ostrich fern: Borealis55, CC0 (licence)
- Otay manzanita: Stan Shebs, CC BY-SA 3.0 (licence)
- Otay Mountain lotus: Justin Paulin, CC BY 4.0 (licence)
- otter bush: Denis.prévôt, CC BY-SA 3.0 (licence)
- otterbossie: H. Zell, CC BY-SA 3.0 (licence)
- Outback Senna, Outback Cassia: Hugo Hulsberg, CC0 (licence)
- ovens wattle: Bidgee, CC BY-SA 3.0 (licence)
- Owlswood Blue Ceanothus: Sergei Gussev, CC BY 2.0 (licence)
- oxbane: Paul venter, CC BY-SA 3.0 (licence)
- oyama magnolia: Sten Porse, CC BY-SA 3.0 (licence)
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Zones: NC North-Central Coastal, CV Central Valley, SC South Coastal, SI South Inland, HD High and Intermediate Desert, LD Low Desert. Ratings: VL very low water, L low, M moderate, H high, ? not rated for that zone, × not suited to that zone. Ratings are the University of California WUCOLS IV list.
How to use this list
- MinutesOpen the calculator with this plant set. The preset city is in a zone where WUCOLS rates the plant. Set your sprinkler type and watering days.
- GuideRead a plant watering guide. Links appear for plants covered by our 1023 written guides.
- PlanBuild your personal watering plan. Put your plants and city together for monthly sprinkler minutes on a printable sheet.
Sources
- WUCOLS IV plant list, University of California, snapshot of the live databaseRead August 23, 2026 on ucanr.edu/sites/WUCOLS
- Appendix C reference evapotranspiration table behind the six zonesRead August 23, 2026 on water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Water-Use-And-Efficiency/MWELO-Rulemaking/Final-MWELO-Text-and-Appendices_20250103.pdf