WateringTimesWatering plan, $19
Thuja plicata, WUCOLS IV

How often to water western red cedar in California

In July in the Central Valley, established western red cedar 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. Western red cedar is a large evergreen conifer native from coastal Alaska south into northern California, with glossy, scale-like leaves in flat, drooping sprays. Grown as a tree it reaches 50 to 70 feet, yet it can be held to a dense hedge as low as 6 feet. It wants consistently moist, well-drained soil and does not tolerate drought or dry winds.

TreeCalifornia nativeRated for 4 of 6 zones

How often to water western red cedar, 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 western red cedar 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 3 inches down at the edge of the root ball signals that western red cedar needs water before it dries further
  • Foliage browning on the windward side after hot, dry wind points to moisture stress
  • A red-brown cast over the foliage in winter is normal seasonal color, not a sign of thirst
  • Yellowing foliage and thinning growth in soggy, airless ground can indicate root rot
  • Spindle-shaped bags hanging from branch tips are bagworms, a pest rather than a watering problem

How to water it

  • Water a young western red cedar over its root ball and nearby soil so the ball never dries out
  • Soak the soil 12 to 18 inches deep, then water again once the top couple of inches dry
  • Spread a thick layer of organic mulch to keep the root zone cool and evenly moist
  • Plant in organic, well-drained, acidic to neutral soil, sheltered from hot, dry winds
  • Run drip along both sides of a hedge so every plant shares the moisture

Through the seasons

Keep a newly planted western red cedar consistently moist through its first summers, since it does not tolerate drought. Established trees still need regular deep soakings through the dry season. The foliage takes on a red-brown green cast in winter and returns to dark green in summer. Hot, dry wind is hard on it, so inland summers call for close soil checks. Across the north-central coast, the Central Valley, the south coast and South Inland, WUCOLS gives western red cedar a moderate water rating. For the high desert and the low desert, WUCOLS marks it as not suited.

In pots

Western red cedar adapts well to containers, and potted plants tend to stay dense and tidy without much pruning. Use a large pot with drainage holes and a rich, slightly acidic mix that holds moisture. In summer heat, check the mix 2 inches down every few days and water before it dries out. Water until excess drains, then empty the saucer. Keep the pot out of hot, drying wind and harsh afternoon sun. In winter, keep the mix lightly moist.

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
0.671.32.02.70.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.671.32.02.70.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Western Red Cedar: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.78––
Feb0.530.650.810.87––
Mar0.871.091.151.3––
Apr1.181.521.41.61––
May1.462.081.611.95––
Jun1.612.481.742.29––
Jul1.612.671.982.51––
Aug1.492.391.862.33––
Sep1.241.81.491.86––
Oct0.871.181.151.33––
Nov0.470.560.840.9––
Dec0.310.340.650.68––
Year1217.1115.518.41––

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 western red cedar. 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 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 JulyRed HorsechestnutAesculus x carneamoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

Rated lower than western red cedar 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 western red cedar, 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 western red cedar in summer?

In July, established western red cedar 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 9 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 western red cedar need per day?

In July in the Central Valley, established western red cedar 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 western red cedar change across California?

Yes. WUCOLS rates western red cedar separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, moderate water in the Central Valley zone, moderate water in the South Coastal zone, moderate water in the South Inland zone, not suited to this region in the High and Intermediate Desert zone, not suited to this region in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Can western red cedar be kept as a hedge?

Yes. Despite its potential to become a very tall tree, regular shearing keeps it as a tight hedge, even one only 6 feet high. Water along the hedge's full length and keep the soil evenly moist.

Why does my western red cedar turn bronze in winter?

Cold weather tints its foliage reddish brown, and dark green returns in summer. That shift is normal. Check the soil only if browning appears during the growing season.

Is western red cedar native to California?

Yes. Its natural range runs from coastal Alaska and Alberta south into northern California.

Does anything grow under western red cedar?

Little grows beneath it, partly because the tree has allelopathic properties that suppress other plants. Cover the root area with mulch rather than trying to plant there. Keep that mulched zone moist along with the tree.

Can you overwater western red cedar?

It handles moist sites such as pond and stream edges, but waterlogged, airless soil can still bring root rot. Keep the soil moist rather than soggy, especially in heavy clay.

More plant watering guides

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Sources