WateringTimesWatering plan, $19
Trachycarpus fortunei, WUCOLS IV

How often to water windmill palm in California

In July in the Central Valley, established windmill 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. Windmill palm is a fan palm from the mountain forests of central and southern China, and one of the more cold-hardy palms. A single trunk wrapped in shaggy brown fiber carries a crown of dark green fans up to 3 feet across. It reaches 20 to 30 feet. It needs well-drained soil, shelter from strong wind and soil that dries between waterings.

TreePalm or cycadRated for 6 of 6 zones

How often to water windmill 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 windmill 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

  • Ground dry 4 to 6 inches down within a couple of feet of the trunk signals that a deep watering is due
  • Stunted, spotted new leaves with pinkish spore masses at their bases point to pink rot, which thrives with excess irrigation and poor drainage
  • Yellowing fronds over soil that stays wet can indicate root rot from overwatering
  • Torn, shredded fans come from strong wind rather than a shortage of water
  • A shaggy coat of brown fiber on the trunk is natural for this palm, not a sign of drought or disease

How to water it

  • Run drip or a soaker in a loop that covers the ground for a few feet around the trunk
  • Let water reach about a foot into the soil each time, pausing between short cycles wherever it puddles or runs off
  • Keep lawn, groundcovers and shrubs at least 2 feet from the trunk, and cover that ring with several inches of mulch
  • Plant at the depth it grew in the nursery, in soil that drains, and avoid moving it in fall or winter
  • Keep sprinkler spray off the crown of a young palm, and enlarge the watered loop as the palm grows

Through the seasons

Plant in spring or summer rather than fall or winter. Water a new palm regularly through its first summer while roots grow into the surrounding soil. The palm stays evergreen. Small yellow flowers hang in summer, and female plants bear dark blue fruit. WUCOLS rates windmill palm low water on the north-central coast and in South Inland. In the Central Valley and on the south coast, it rates moderate water. The high desert and the low desert carry a moderate water rating as well. Cool, damp coastal winters favor pink rot, so hold off on irrigation while rain keeps the soil moist.

In pots

Windmill palm is one of the palms that does well in a large patio container. Pick a heavy pot that will not tip in wind, with wide holes in the base and a coarse, well-drained mix. When summer heat arrives, test the mix to the depth of a knuckle or two every few days, and water once it feels dry there. Pour until water flows out below, then tip out the saucer. Park the pot out of strong wind, which shreds the fans. Through winter, water sparingly, since cold, soggy mix leads to rot.

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

Windmill 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 windmill 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 windmill 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 windmill 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 windmill palm in summer?

In July, established windmill 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 windmill palm need per day?

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

Yes. WUCOLS rates windmill 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.

Why are my windmill palm leaves torn?

Strong wind tears the fans. The damage is unsightly but not fatal. Plant it where buildings or trees break the wind, or choose the dwarf Chusan palm, which handles wind better.

Should I remove the fiber from my windmill palm trunk?

No. The fiber is what remains of old leaf bases, and it is part of the palm's look. Pulling leaf bases off early can tear and wound the trunk, which opens the way for pink rot.

Why doesn't my windmill palm have fruit?

Windmill palms are either male or female, and only female plants bear the dark blue fruit. A female also needs a male nearby to set seed.

Can you overwater a windmill palm?

Yes. Excess irrigation, poor drainage and airless soil stress it and invite pink rot and root rot. Let the upper soil dry before the next deep watering.

What is a dwarf Chusan palm?

It is a compact form of windmill palm, sold as 'Wagnerianus', that grows 12 to 20 feet tall. Its leaves are smaller and stiffer, on shorter stalks, and it copes better with wind and coastal conditions.

How cold hardy is windmill palm?

For a palm, its winter hardiness is excellent, which makes it a common choice in cooler gardens. It can still suffer in the coldest locations. Shelter it from cold, drying winds.

More plant watering guides

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Sources