WateringTimesWatering plan, $19
Paulownia tomentosa, WUCOLS IV

How often to water empress tree in California

In July in the Central Valley, established empress tree 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. Empress tree is a very fast-growing deciduous tree from China with huge, velvety, heart-shaped leaves. Big clusters of fragrant lavender flowers open in spring. It prefers deep, moist, well drained sandy loam and full sun. It reseeds freely and resprouts from its roots, so choose its spot with care.

TreeRated for 4 of 6 zones

How often to water empress 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 empress 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

  • Soil dry 4 inches down near the canopy edge of a young empress tree means it is ready for a deep soak
  • Huge leaves hanging limp on hot afternoons and still drooping at dusk point to a dry root zone
  • Leaves yellowing over soil that stays waterlogged point to poor drainage, since it prefers well drained ground
  • Flower buds that brown and drop after a late frost show cold damage, not thirst
  • Shoots rising from the roots after a cut or injury are its normal sprouting habit, not a watering sign

How to water it

  • Water a young tree over the root ball and a wide ring beyond it, enlarging the ring as it races upward
  • Soak to about 18 inches through summer, letting the top few inches dry between waterings
  • Plant in full sun in deep, well drained sandy loam, away from low spots that stay wet
  • Keep a wide mulch ring over the roots, since little grows well in its dense shade
  • Pull the seedlings that sprout in irrigated beds nearby before they root deeply

Through the seasons

Water a new empress tree regularly through its first summer while it puts on very fast growth. Established trees still need deep summer soakings in dry California weather to support their huge leaves. Flower buds form the season before and open in spring, and a late frost can damage them. Woody capsules split in fall to release winged seeds. Winter rain covers the bare months on the coast and in the valley. WUCOLS rates empress tree moderate water in the Central Valley, in South Inland, on the north-central coast and on the south coast. WUCOLS has not evaluated it for the high desert and marks it as not suited to the low desert.

In pots

Empress tree soon outgrows any container, so pot culture only suits a seedling waiting to be planted. Its huge leaves draw water quickly, so check the mix daily in summer heat and water once the top 2 inches are dry. Let it drain thoroughly and empty the saucer each time. Plant it out while it is young, and keep the leafless seedling just barely moist through winter.

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

Empress Tree: 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 empress tree. 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 empress tree 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 empress 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 empress tree in summer?

In July, established empress tree 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 empress tree need per day?

In July in the Central Valley, established empress tree 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 empress tree change across California?

Yes. WUCOLS rates empress tree 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 evaluated 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.

How fast does empress tree grow?

Very fast, adding up to about 15 feet a year when young and reaching about 50 feet in ten years. Give it plenty of room and steady summer water while it establishes.

Is empress tree invasive?

It reseeds freely and is listed as invasive in parts of the eastern United States. Cut trees resprout from roots many feet away. Pull seedlings early, and think twice before planting one.

Why didn't my empress tree flower?

Its flower buds form a season ahead, so a late frost can kill them before they open. Pruning off last year's growth also removes the buds. Watering does not change either cause.

Can anything grow under an empress tree?

Little thrives in its dense shade. Use mulch under the canopy rather than thirsty plants that need extra water there.

Is empress tree wood strong?

No. The wood is weak, so limbs can break in strong wind. Keep it well away from houses, cars and play areas.

More plant watering guides

White ForsythiaPaperbark MapleSilver MapleJapanese BeautyberryEastern DogwoodHeathsBorder ForsythiaAlgerian Ivy

Sources