WateringTimesWatering plan, $19
Styphnolobium japonicum (Sophora japonica), WUCOLS IV

How often to water Japanese pagoda tree in California

In July in the Central Valley, established Japanese pagoda tree in loam needs a deep watering about every 20 days: about 55 gallons each time under a 10 foot canopy, about 19 gallons a week. Japanese pagoda tree is a broad, deciduous shade tree in the pea family, with sprays of fragrant, creamy white flowers in late summer. A young tree needs deep soakings while its roots spread. Once established it handles heat and short dry spells well, and it flowers best after a hot summer.

TreeRated for 6 of 6 zones

How often to water Japanese pagoda tree, 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 Japanese pagoda tree 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

  • Dry soil 4 inches down at the edge of a young tree's root ball means it is time for a deep soak
  • Drooping, pale leaflets on a young tree during a heat wave point to a dry root zone
  • Leaves browning and dropping in midsummer, well before the brief yellow fall color, can follow a long dry spell
  • Leaves that wilt and yellow while the soil stays soggy for days point to poor drainage rather than thirst
  • Wilting on one side of the crown while the soil is moist can mean verticillium wilt, which watering will not cure

How to water it

  • Water a young pagoda tree over its root ball and a band of soil beyond it, then widen that band as the crown spreads
  • Apply water slowly until it reaches about 18 inches down, then let the top few inches dry before the next soak
  • Set drip emitters or a soaker ring under the outer canopy of an older tree, keeping water off the trunk
  • Spread a wide ring of wood chip mulch over the root zone, pulled a few inches back from the trunk
  • Plant in loam or sandy soil that drains well, and avoid low spots where winter water stands

Through the seasons

Give a new pagoda tree deep soakings through its first two or three summers, widening the wet area as roots spread. Established trees need fewer, deeper waterings. Leaves emerge in spring and the tree blooms in July and August, so summer soil checks matter most. Leaves hold green late into fall, then drop, and the bare tree rests through winter. Winter rain covers the cool months on the north-central coast and in the Central Valley, where WUCOLS rates it low water. It rates moderate water on the south coast, in South Inland, in the high desert and in the low desert. In both deserts, check the soil during long dry winter spells.

In pots

A pagoda tree only belongs in a container while it is young, before it goes in the ground. Check a nursery can 2 to 3 inches down every few days in summer, and daily during valley or desert heat waves. Water until it runs from the drainage holes, then empty the saucer so the roots are not left standing in water. A dark plastic can on hot paving heats quickly, so shade the pot itself. In winter the leafless tree uses little water, so let the mix dry a little more between soakings.

1 Your climate zone six WUCOLS zones, each from its own reference city
1.07gal per sq ft in JulyLow water use in the Central Valley zone
A year
6.84 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.761.52.33.00.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.761.52.33.00.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.780.780.740.78
Feb0.210.260.810.870.930.93
Mar0.350.431.151.31.461.52
Apr0.470.611.41.611.891.95
May0.580.831.611.952.392.45
Jun0.640.991.742.292.852.79
Jul0.641.071.982.513.042.85
Aug0.60.951.862.332.792.6
Sep0.50.721.491.862.142.08
Oct0.350.471.151.331.461.49
Nov0.190.220.840.90.930.96
Dec0.120.140.650.680.650.68
Year4.86.8415.518.4121.2721.08

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 low water in the Central Valley, like Japanese pagoda tree. Plants that drink alike can share one valve and one schedule.

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 Japanese pagoda tree, 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 pagoda tree in summer?

In July, established Japanese pagoda tree in loam needs a deep watering about every 20 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 Japanese pagoda tree need per day?

In July in the Central Valley, established Japanese pagoda tree needs about 2.7 gallons a day under a 10 foot canopy and about 11 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 Japanese pagoda tree change across California?

Yes. WUCOLS rates Japanese pagoda tree separately for each of the six California climate zones: low water in the North-Central Coastal zone, low 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.

Why is my pagoda tree not flowering?

Age is the usual reason. A young tree can take up to ten years to bloom, and the heaviest flowering comes on much older trees. Hot summers and full sun improve the display, so keep up normal deep soakings and wait.

Are pagoda tree pods poisonous?

Yes. The seeds and pods are reported to be toxic and should not be eaten. The pods hang on through winter and then fall, so rake them up where children or pets play.

Can a pagoda tree grow in a lawn?

Yes, it is often planted as a lawn, street or park tree. Lawn sprinklers wet only the top few inches, so give the tree its own deep soak during long dry spells. Keep turf and its spray a few feet back from the trunk.

Why do pagoda tree branches break?

The wood is fairly weak, so wind can split long or poorly attached limbs. Prune a young tree to space its main branches and build a sturdy frame. Watering does not change wood strength.

Why is one side of my pagoda tree wilting?

Verticillium wilt often shows first on one side of a tree or in scattered branches. Damage tends to appear in warm weather, when the tree is under the most stress. Keep the tree on deep, spaced soakings and have a branch sample checked before blaming water.

When does a pagoda tree drop its flowers?

The creamy white flowers fall in late summer and can carpet the ground under the tree. Keep the litter off drip emitters and paths. Seed pods follow and stay on the branches into winter.

More plant watering guides

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Sources