WateringTimesWatering plan, $19
Berberis thunbergii & ssp. & cvs., WUCOLS IV

How often to water Japanese barberry in California

In July in the Central Valley, established Japanese barberry 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. Japanese barberry is a dense, thorny deciduous shrub from Japan, usually 3 to 6 feet tall, with small rounded leaves on arching, spiny stems. Pale yellow spring flowers hide under the foliage, bright red berries follow, and the leaves turn red, orange or yellow in fall. Its many cultivars range from red, gold or green 1-foot mounds to narrow 8-foot columns.

ShrubRated for 6 of 6 zones

How often to water Japanese barberry, 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 Japanese barberry 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

  • When the soil under the canopy is dry a few inches down in summer, give the shrub a deep soak
  • Wilting and dieback in soggy, poorly drained soil can point to root rot
  • Leaf spots and blackened shoots in wet weather point to anthracnose or bacterial leaf spot rather than thirst
  • Seedlings appearing away from the shrub come from bird-spread berries, not from irrigation
  • In the deserts, leaves crisping in summer heat mean the shrub needs deeper, more regular water

How to water it

  • Water at the base with drip, wetting the root zone about 12 inches deep
  • Let the top couple of inches dry between soakings, except in the deserts, where it needs regular deep water
  • Plant in sun to part shade in well-drained soil
  • Choose a sterile or less invasive cultivar, and pull seedlings that appear nearby
  • Wear thick gloves when pruning, since the stems carry a spine at each node

Through the seasons

Water new shrubs regularly through their first summer. Leaves and flowers emerge in spring, color red, orange or yellow in fall and drop for winter, leaving red berries on bare stems. Winter rain usually covers dormant shrubs on the coast and in the Central Valley. Desert plantings need deep, regular summer water. WUCOLS rates Japanese barberry moderate water on the north-central coast, in the Central Valley and in South Inland. It rates low water on the south coast. The high desert and the low desert rate high water.

In pots

Dwarf barberries such as 'Crimson Pygmy' stay 1 to 2 feet tall, a good size for containers. Use a well-drained mix in a pot with drainage holes, in sun to part shade. In warm weather, feel the mix every few days and water when the top 2 inches are dry, checking more often in desert heat. Let excess drain, then empty the saucer. After leaf drop, water only when the mix dries.

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
1.22.43.64.90.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC1.22.43.64.90.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Japanese Barberry: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.310.781.191.24
Feb0.530.650.320.871.491.49
Mar0.871.090.461.32.332.43
Apr1.181.520.561.613.033.12
May1.462.080.641.953.823.92
Jun1.612.480.692.294.564.46
Jul1.612.670.792.514.864.56
Aug1.492.390.742.334.464.17
Sep1.241.80.61.863.423.32
Oct0.871.180.461.332.332.38
Nov0.470.560.330.91.491.54
Dec0.310.340.260.681.041.09
Year1217.116.218.4134.0333.73

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 Japanese barberry. 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 JulyArborvitaeThuja occidentalis ssp. & 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 July

Similar plants that need less water 16

Rated lower than Japanese barberry 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 Japanese barberry, 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 Japanese barberry in summer?

In July, established Japanese barberry 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 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 Japanese barberry need per day?

In July in the Central Valley, established Japanese barberry 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 Japanese barberry change across California?

Yes. WUCOLS rates Japanese barberry separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, moderate water in the Central Valley zone, low water in the South Coastal zone, moderate water in the South Inland zone, high water in the High and Intermediate Desert zone, high 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 Japanese barberry invasive?

It is invasive in parts of eastern North America, spreading by root suckers and by seed that birds carry. Some cultivars may also have invasive potential, while others are sterile. Choose a sterile selection and pull stray seedlings.

Which Japanese barberry stays small?

'Crimson Pygmy' and 'Bagatelle' stay 1 to 2 feet tall with deep red leaves, and 'Bogozam' is a gold-leaved form of the same size. 'Helmond Pillar' grows 6 to 8 feet tall but only 1 to 2 feet wide.

Why are my barberry leaves spotted?

Anthracnose and bacterial leaf spot can mark the leaves, especially in wet weather. In poorly drained soil, root rot can also cause wilting and dieback.

Is Japanese barberry safe around children?

Its stems carry sharp spines, so keep it away from play areas and paths. Wear gloves when pruning or pulling seedlings.

Can you overwater Japanese barberry?

Yes. It needs well-drained soil, and ground that stays soggy can lead to root rot. Let the upper soil dry between soakings outside the deserts.

More plant watering guides

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Sources