WateringTimesWatering plan, $19
Washingtonia filifera, WUCOLS IV

How often to water California fan palm in California

In July in the Central Valley, established California fan palm in loam needs a deep watering about every 8 days: about 55 gallons each time under a 10 foot canopy, about 47 gallons a week. California fan palm is the only palm native to California, found wild around springs, seeps and streams in the southeastern deserts. It builds a massive, columnar trunk 30 to 60 feet tall, crowned with waxy gray-green fans on spiny stalks. Dead fronds hang on as a dense brown skirt. It needs sun, soil that drains and deep watering through the dry months.

TreePalm or cycadCalifornia nativeRated for 6 of 6 zones

How often to water California fan palm, month by month

Your city
Canopy width
10 ft
Your soil

Type your city above and the days between waterings and the gallons appear here, worked out from your city's climate table. Or read the figures by climate zone further down.

Every month, on your water days. The personal plan prints this for California fan palm and the rest of your yard, on the days your water supplier allows.Get the plan for $19

How this is worked out: established roots fill the top 1.5 feet of soil, and you water again when that soil has dried halfway. Loam soil holds about 1.5 inches of water per foot. Water the whole area under the branches, and skip a watering after a good soaking rain.

Which soil do you have?

Dig down a few inches, take a handful of moist soil and squeeze it.

  • Sandy: gritty, falls apart when you open your hand, will not form a ball.
  • Loam: forms a soft ball that crumbles when you poke it.
  • Clay: forms a firm, sticky ball and squeezes out into a ribbon between thumb and finger.

Still not sure? Pick loam. Most garden beds sit between sand and clay.

How to measure canopy width

A tree with its canopy width marked across the widest branches and the circle under it shaded blue

Measure across the branches, from the tips of the outer leaves on one side to the tips on the other. A tape works, or pace it out.

Water the whole circle under the branches, shown in blue. The gallons here cover that circle.

A wider canopy means more gallons each watering, not more waterings. While the tree is young, measure again each spring.

How to tell it needs water

  • On a young palm, a probe that meets dry soil a few inches below the mulch means the root ball needs a deep watering
  • Lower fans yellowing early and dotted with shiny black, diamond-shaped specks point to diamond scale, a fungal disease, not thirst
  • New fans damaged each late spring, scattered among healthy ones and sometimes dusted pink, signal pink rot, which soggy soil makes worse
  • Fan segments dying in a wedge pattern above a dark streak on the leaf stalk point to a blight, not a water shortage
  • A thick brown skirt of dead fronds hugging the trunk is this palm's natural thatch, not drought damage

How to water it

  • Water a newly set palm inside a 4 to 6 inch earth ring, keeping the root ball moist but not saturated
  • Run a separate, deep cycle that wets the soil down to 2 feet, rather than relying on turf sprinklers
  • Keep sprinkler spray off the trunk and crown, since a wet bud can rot and salts can crust on the trunk
  • Set the root ball at its original depth in soil that drains, and backfill with the same soil you dug out
  • Mulch 3 to 4 inches deep over a plant-free circle around the trunk, and widen the watered area as the palm matures

Through the seasons

Set new palms out between late spring and early fall, when roots grow fastest, and keep them steadily watered until they establish. Creamy white flower clusters hang from the crown in spring or early summer, and small reddish black fruits follow. Cool, moist winters and springs favor pink rot and diamond scale near the coast, so skip irrigation while rain keeps the ground damp. WUCOLS rates California fan palm moderate water in the Central Valley, on the south coast, in the high desert and in the low desert. On the north-central coast and in South Inland, it rates low water.

In pots

California fan palm grows a heavy trunk, so a container is only a nursery stage for a young plant. Use a wide, weighty pot with open drainage holes and a coarse, gritty mix. In summer heat, dig a finger 2 inches into the mix every few days and water when it is dry at that depth. Let water pour from the base, and keep the pot raised above any standing water. Plant it out between late spring and early fall. In winter, water only after the mix has dried.

1 Your climate zone six WUCOLS zones, each from its own reference city
2.67gal per sq ft in JulyModerate water use in the Central Valley zone
A year
17.11 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.761.52.33.00.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.761.52.33.00.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

California Fan Palm: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.40.780.310.740.78
Feb0.210.650.810.350.930.93
Mar0.351.091.150.521.461.52
Apr0.471.521.40.641.891.95
May0.582.081.610.782.392.45
Jun0.642.481.740.922.852.79
Jul0.642.671.9813.042.85
Aug0.62.391.860.932.792.6
Sep0.51.81.490.742.142.08
Oct0.351.181.150.531.461.49
Nov0.190.560.840.360.930.96
Dec0.120.340.650.270.650.68
Year4.817.1115.57.3721.2721.08

How this is worked out: the WUCOLS water rating for each zone times that zone’s climate for the month. A dash means WUCOLS does not rate the plant there. The figures are what the plant uses, before sprinkler losses.

Plants with the same water needs 16

Rated moderate water in the Central Valley, like California fan palm. Plants that drink alike can share one valve and one schedule.

Citrus TreesCitrus spp.moderate water, Central Valley2.67 gal/sq ft in JulyJapanese MapleAcer palmatummoderate water, Central Valley2.67 gal/sq ft in JulyAvocado TreesPersea americanamoderate water, Central Valley2.67 gal/sq ft in JulyMagnolia TreesMagnolia grandiflora ssp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyPalm TreesSyagrus romanzoffiana (Arecastrum romanzoffianum)moderate water, Central Valley2.67 gal/sq ft in JulySago PalmCycas revolutamoderate water, Central Valley2.67 gal/sq ft in JulyApple TreesMalus spp. (edible) e.g, 'Anna' (low chill variety for low desert)moderate water, Central Valley2.67 gal/sq ft in JulyPeach TreesPrunus spp. ediblemoderate water, Central Valley2.67 gal/sq ft in JulyPersimmon TreesDiospyros kakimoderate water, Central Valley2.67 gal/sq ft in JulyAmur MapleAcer ginnalamoderate water, Central Valley2.67 gal/sq ft in JulyFernleaf MapleAcer japonicummoderate water, Central Valley2.67 gal/sq ft in JulyBox ElderAcer negundomoderate water, Central Valley2.67 gal/sq ft in JulyNorway MapleAcer platanoidesmoderate water, Central Valley2.67 gal/sq ft in JulyRed MapleAcer rubrummoderate water, Central Valley2.67 gal/sq ft in JulyChinese MapleAcer truncatummoderate water, Central Valley2.67 gal/sq ft in JulyRed BuckeyeAesculus paviamoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

Rated lower than California fan palm in the Central Valley. Worth a look for a new bed or a lawn replacement.

Olive TreesOlea europaea ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyFig TreesFicus carica ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyCrape MyrtleLagerstroemia spp., hybrids & cvs.low water, Central Valley1.07 gal/sq ft in JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyPomegranate TreesPunica granatumlow water, Central Valley1.07 gal/sq ft in JulyEucalyptusEucalyptus polyanthemoslow water, Central Valley1.07 gal/sq ft in JulyPine TreesPinus canariensislow water, Central Valley1.07 gal/sq ft in JulyJunipersJuniperus spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyTexas Red OakQuercus buckleyilow water, Central Valley1.07 gal/sq ft in JulyPortuguese OakQuercus faginealow water, Central Valley1.07 gal/sq ft in JulySoapbark TreeQuillaja saponarialow water, Central Valley1.07 gal/sq ft in JulyNecklace TreeSophora affinislow water, Central Valley1.07 gal/sq ft in JulyBailey AcaciaAcacia baileyanalow water, Central Valley1.07 gal/sq ft in JulySilver WattleAcacia dealbatalow water, Central Valley1.07 gal/sq ft in JulyGreen WattleAcacia decurrenslow water, Central Valley1.07 gal/sq ft in JulySydney Golden WattleAcacia longifolialow water, Central Valley1.07 gal/sq ft in July
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes California fan palm, your sprinkler type and the month, and gives the minutes per water day for that supplier's schedule. Or put it in a zone of the personal watering plan and get all twelve months printed.

Questions people ask

How often should I water California fan palm in summer?

In July, established California fan palm in loam needs a deep watering about every 8 days in the Central Valley, about every 11 days on the south coast and about every 22 days in the South Inland zone. Sandy soil holds less water, so waterings come closer together. Clay stretches them. Check the soil before each watering and skip one after a soaking rain.

How much water does California fan palm need per day?

In July in the Central Valley, established California fan palm needs about 6.8 gallons a day under a 10 foot canopy and about 27 gallons a day under a 20 foot canopy. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for California fan palm change across California?

Yes. WUCOLS rates California fan palm separately for each of the six California climate zones: low water in the North-Central Coastal zone, moderate water in the Central Valley zone, moderate water in the South Coastal zone, low water in the South Inland zone, moderate water in the High and Intermediate Desert zone, moderate water in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Is California fan palm native to California?

Yes. It is the only palm native to the state, growing wild at desert springs, seeps and streams in southeastern California and Baja California. Scattered populations also grow in Arizona and southern Nevada.

Should I trim the skirt on a California fan palm?

That is a matter of taste. The skirt is natural and some people prize it, but it can shelter rodents and raises fire risk near buildings. If you trim, cut only dead fronds and leave the leaf bases until they dry.

What are the black spots on my California fan palm leaves?

Shiny black, diamond-shaped specks are the fruiting bodies of diamond scale, a fungus rather than an insect. It is common near the coast and rare in the Central Valley and the deserts. Keep the palm vigorous with regular summer irrigation and a deep soak in dry winters.

How big does California fan palm get?

It reaches 30 to 60 feet tall, with a crown 10 to 20 feet wide and a very heavy trunk. It can overwhelm a small garden, so it suits parks, streets and large properties best.

Can you overwater California fan palm?

Yes. Palms are sensitive to poor drainage, and excess irrigation sets up pink rot, which hits this palm often. Let the upper soil dry between deep waterings.

Is California fan palm cold hardy?

Yes, for a palm. It takes lows of about 10 degrees F where it grows wild in the desert. Freeze damage can still stress it and open the way to pink rot.

More plant watering guides

Spider PlantYaupon HollyRed Hot PokerSunshine Chinese PrivetMugo PineCamphor TreeCreeping FigWhite Forsythia

Sources