WateringTimesWatering plan, $19
Thuja occidentalis ssp. & cvs., WUCOLS IV

How often to water arborvitae in California

In July in the Central Valley, established arborvitae in loam needs a deep watering about every 8 days: about 8.8 gallons each time for a plant 4 feet across, about 7.6 gallons a week. Arborvitae forms an evergreen screen of soft, scale-like sprays over shallow, fibrous roots. Dry spells in hot inland gardens can leave lasting brown patches in a hedge. Keep its roots evenly moist without leaving the ground saturated.

ShrubRated for 6 of 6 zones

How often to water arborvitae, month by month

Your city
Plant width
4 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 arborvitae 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 the plant covers, 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 plant width

A shrub with its width marked from one side to the other and the circle under it shaded blue

Measure across the plant, from the tips of the leaves on one side to the tips on the other.

Water the whole area the plant covers, shown in blue. The gallons here cover that area.

A wider plant means more gallons each watering, not more waterings. While it is young, measure again each spring.

How to tell it needs water

  • Soil dry 2 to 3 inches down beneath the hedge signals that arborvitae needs a moisture check across its root strip
  • Dull gray-green sprays with brittle tips can signal thirst when the soil beneath them is dry
  • Brown sprays rarely recover from bare inner wood, so check moisture before the hedge reaches that stage
  • Yellowing inner foliage over soggy ground can indicate poor drainage around the shallow roots
  • Browning on the sunny, wind-facing side can accompany dry soil, so compare moisture along the row

How to water it

  • Water the strip beneath the hedge and beyond its branch tips while keeping trunks dry
  • Soak the top foot of soil slowly, then let the surface dry slightly before watering again
  • Run drip tubing along both sides of the row and expand coverage as the hedge widens
  • Spread wood-chip mulch over the root strip, leaving a gap around each trunk
  • Plant arborvitae on a low berm in heavy clay, and pause watering whenever the soil remains saturated

Through the seasons

Check a new arborvitae root ball often through its first summer, keeping it evenly moist as roots spread. Established screens can take deeper, less frequent soakings. These evergreen hedges still use some moisture in winter, though demand eases with cooler weather. Irrigation matters most from late spring through early fall. Coastal and Central Valley rain often supplies the cool months; check desert plantings through dry winter spells. WUCOLS rates arborvitae moderate water in all six climate zones.

In pots

A container arborvitae has little soil to buffer its shallow roots against California heat. Check the top two inches of mix often as temperatures climb. Water when that layer dries, letting excess drain freely through the holes, then empty the saucer. Keep the mix moist without leaving roots submerged. Winter wind can also dry an exposed pot, so continue checking through cool weather and water on mild days when needed.

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

Arborvitae: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.780.740.78
Feb0.530.650.810.870.930.93
Mar0.871.091.151.31.461.52
Apr1.181.521.41.611.891.95
May1.462.081.611.952.392.45
Jun1.612.481.742.292.852.79
Jul1.612.671.982.513.042.85
Aug1.492.391.862.332.792.6
Sep1.241.81.491.862.142.08
Oct0.871.181.151.331.461.49
Nov0.470.560.840.90.930.96
Dec0.310.340.650.680.650.68
Year1217.1115.518.4121.2721.08

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 arborvitae. Plants that drink alike can share one valve and one schedule.

RosesRosa hybrids..bushmoderate water, Central Valley2.67 gal/sq ft in JulyAzaleasRhododendron spp. (CA native and non-native spp.)moderate water, Central Valley2.67 gal/sq ft in JulyCamelliasCamellia japonica (SHADE IN DESERT)moderate water, Central Valley2.67 gal/sq ft in JulyGardeniasGardenia spp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBird of ParadiseStrelitzia reginae (shade in desert)moderate water, Central Valley2.67 gal/sq ft in JulyHibiscusHibiscus rosa-sinensismoderate water, Central Valley2.67 gal/sq ft in JulySago PalmCycas revolutamoderate water, Central Valley2.67 gal/sq ft in JulyStar JasmineTrachelospermum jasminoides and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBambooBambusa spp.moderate water, Central Valley2.67 gal/sq ft in JulyLilacsSyringa hybrids (including Descanso hybrids)moderate water, Central Valley2.67 gal/sq ft in JulySpireaSpiraea spp. (CA native and non native spp.)moderate water, Central Valley2.67 gal/sq ft in JulyButterfly BushBuddleja davidii and hybridsmoderate water, Central Valley2.67 gal/sq ft in JulySageSalvia officinalis and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyRed BuckeyeAesculus paviamoderate water, Central Valley2.67 gal/sq ft in JulyWestern ServiceberryAmelanchier alnifoliamoderate water, Central Valley2.67 gal/sq ft in JulyJapanese AucubaAucuba japonica (SHADE)moderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

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

LavenderLavandula spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRosemaryRosmarinus officinalislow water, Central Valley1.07 gal/sq ft in JulyBougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyOlive TreesOlea europaea 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 JulyLantanaLantana camara ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyJunipersJuniperus spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySagebrushArtemisia spp. (shrubby)low water, Central Valley1.07 gal/sq ft in JulyWild PrivetLigustrum vulgarelow water, Central Valley1.07 gal/sq ft in JulyCoralberrySymphoricarpos orbiculatus (SHADE)low water, Central Valley1.07 gal/sq ft in JulySydney Golden WattleAcacia longifolialow water, Central Valley1.07 gal/sq ft in JulyBlue Leaf WattleAcacia salignalow 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 arborvitae, 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 arborvitae in summer?

In July, established arborvitae 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 arborvitae need per day?

In July in the Central Valley, established arborvitae needs about 1.1 gallons a day for a plant 4 feet across and about 4.3 gallons a day for a plant 8 feet across. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for arborvitae change across California?

Yes. WUCOLS rates arborvitae 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, 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.

How do I water arborvitae after planting?

Feel the nursery root ball separately from the soil beside it. It can dry faster than the surrounding ground, leaving a new hedge thirsty despite damp soil nearby. Direct water over the ball first, then widen coverage as roots spread.

When should I start watering arborvitae in spring?

Check beneath the mulch when winter storms end. Spring growth helps fill the screen, so begin soaking when the root strip starts to dry rather than waiting for dull sprays.

How do I water arborvitae in clay?

The shallow root mat needs air as well as moisture. Apply water gently and check that the ground drains between soakings. If it stays wet, wait before running the hedge line again.

Why is my arborvitae turning bronze?

Some arborvitae cultivars bronze naturally in winter and green again in spring. Fine stippling or persistent browning warrants a mite inspection and soil check.

Does arborvitae need water in fall?

Continue checking during warm, dry autumn weather, especially on a new hedge. Ease irrigation as days cool and storms moisten the soil. Late heat can still dry a small root ball.

Which parts of an arborvitae hedge need winter checks?

Look beneath eaves and on the sunny side of the row. These spots can remain dry while exposed ground receives rain. Soak only where a check at root depth shows a shortage.

More plant watering guides

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Sources