WateringTimesWatering plan, $19
Washingtonia robusta, WUCOLS IV

How often to water Mexican fan palm in California

In July in the Central Valley, established Mexican 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. Mexican fan palm is a fast, very tall palm with a slender trunk topped by bright green fans on spiny leaf stalks. Dead fronds hang on as a brown skirt unless they are removed. Like other palms, it grows new roots from the trunk base instead of a taproot, and it is sensitive to poor drainage around them.

TreePalm or cycadRated for 6 of 6 zones

How often to water Mexican 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 Mexican 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

  • Soil dry 6 inches down in the root zone of a young Mexican fan palm means it needs a deep watering
  • New fronds that stay small on a young palm can follow a root ball that dried out during establishment
  • Older fronds yellowing evenly can point to a nitrogen shortage rather than a watering problem
  • Yellow mottling on older fronds suggests potassium deficiency, which water alone will not correct
  • A rotting spear leaf at the crown after sprinkler spray points to bud rot from water sitting in the crown

How to water it

  • Build a low berm around a new Mexican fan palm's root ball and fill it slowly so the whole ball is wetted
  • Water established palms deeply, to about 2 feet, instead of the light, frequent cycles used for lawn
  • Keep a mulched, plant-free strip at least a foot wide around the trunk so turf sprinklers do not hit it
  • Plant at the same depth it grew before, in soil that drains, since palms are sensitive to poor drainage
  • Spread water over a wider area as the palm ages and its fibrous roots range out from the trunk base

Through the seasons

Supplemental water matters most for a newly planted Mexican fan palm until its roots establish. Planting from late spring to early fall matches its season of fastest root growth. Established palms take deep soakings with dry periods between. The palm is evergreen and grows all its new fronds from a single bud at the crown. Winter rain usually covers the coast and the Central Valley, while desert palms need checks in dry winters. WUCOLS rates Mexican fan palm low water on the north-central coast, on the south coast and in South Inland. It rates moderate water in the Central Valley, the high desert and the low desert.

In pots

A young Mexican fan palm can live in a large container for a few years before its fast growth outpaces it. Use a heavy pot with drainage holes and a coarse, fast-draining mix. In summer heat, check 2 inches down every few days and water when that layer is dry. Water until it drains out, then empty the saucer. In winter, water lightly and only when the mix has dried, since soggy roots invite trouble in a pot.

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

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.40.310.310.740.78
Feb0.210.650.320.350.930.93
Mar0.351.090.460.521.461.52
Apr0.471.520.560.641.891.95
May0.582.080.640.782.392.45
Jun0.642.480.690.922.852.79
Jul0.642.670.7913.042.85
Aug0.62.390.740.932.792.6
Sep0.51.80.60.742.142.08
Oct0.351.180.460.531.461.49
Nov0.190.560.330.360.930.96
Dec0.120.340.260.270.650.68
Year4.817.116.27.3721.2721.08

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 Mexican 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 Mexican 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 Mexican 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 Mexican fan palm in summer?

In July, established Mexican fan palm in loam needs a deep watering about every 8 days in the Central Valley, about every 27 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 Mexican fan palm need per day?

In July in the Central Valley, established Mexican 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 Mexican fan palm change across California?

Yes. WUCOLS rates Mexican 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, low 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.

Should I remove the dead fronds on my Mexican fan palm?

Many people do, since dead fronds can shelter rodents and add fire risk. On this palm they also tend to break loose on their own and fall without warning. Never cut green fronds, and never prune from below a hanging frond bundle.

Why are the lower fronds on my palm turning yellow?

Older fronds that yellow evenly often signal a nitrogen shortage, while yellow mottling points to potassium. Palm fertilizer spread under the canopy helps, followed by a deep watering. Discolored fronds do not recover, so judge progress by new growth.

Can Mexican fan palm grow in a lawn?

It can, but give it a mulched, grass-free strip around the trunk. Lawn sprinklers water too often and too shallowly for a palm and can wet the crown. Run separate, deeper watering for the palm.

How tall does Mexican fan palm get?

It grows fast and can reach 40 to 100 feet over its life, on a slender trunk. Plant it where the crown will stay clear of wires and roofs.

Is Mexican fan palm invasive?

It self-sows and can become weedy where soil stays moist. Pull seedlings while they are small, and avoid keeping the beds around the palm soggy.

Can you overwater Mexican fan palm?

Yes. Palms are sensitive to poor drainage, and water sprayed into the crown can rot the bud. Water the root zone deeply, then let the top several inches dry.

More plant watering guides

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Sources