WateringTimesWatering plan, $19
Brachychiton populneus, WUCOLS IV

How often to water bottle tree in California

In July in the Central Valley, established bottle 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. Bottle tree, also called kurrajong, is a fast-growing Australian shade tree with a dense, evergreen crown of glossy, poplar-like leaves. Its stout green trunk is thick, though less swollen than some of its relatives. Small cream to pale pink bells, speckled red inside, give way to leathery, canoe-shaped seed pods. Once settled it needs little water in most of California.

TreeRated for 6 of 6 zones

How often to water bottle 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 bottle 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

  • When dryness reaches 4 to 6 inches deep at the outer edge of a young bottle tree's root ball, a deep soak is due
  • Dull, drooping leaves on a young tree during a heat wave, with dry soil below, point to a thirsty root zone
  • Yellowing leaves and a thinning crown while the soil stays wet for days point to root rot, which this tree is prone to
  • Tiny, perfectly round holes in the trunk or branches, sometimes with wet stains, call for a shothole borer check rather than more water

How to water it

  • Direct water onto a young bottle tree's root ball and a collar of soil just past it, enlarging the collar as the crown grows
  • Water slowly enough that moisture sinks about 18 inches deep, then hold the next soak until the top several inches are dry
  • For an older tree, lay a soaker ring or drip emitters beneath the outer canopy, and keep the trunk itself dry
  • Choose a well-drained site with loam or sandy soil, never a hollow where rainwater collects and stands
  • Mulch the root zone with wood chips, leaving a few inches of bare soil around the green trunk

Through the seasons

For the first two or three summers after planting, soak a young bottle tree deeply, and let the wetted area grow outward with the roots. Mature trees manage on fewer, deeper waterings. As an evergreen it holds its crown year round, blooms in spring and summer, and forms its dry seed pods in summer and fall. It is native to a summer rain climate, yet it grows well where California's rain falls in winter. On the coast and in the Central Valley, that winter rain does the cool-season watering. WUCOLS rates it low water on the north-central coast and the south coast, and also in the Central Valley and South Inland. Both the high desert and the low desert carry a moderate water rating, and summer soil checks matter more there.

In pots

Fast growth and eventual size mean a bottle tree cannot stay in a container for long. Until planting, a young tree can live in a large, deep nursery can. In summer heat, test the mix 2 to 3 inches deep every few days, and daily through desert heat waves. Water until the excess flows out the bottom, then empty the saucer, because this tree is prone to root rot. Dark cans sitting on hot paving warm up fast, so put the pot itself in shade. Through winter, allow the mix to get slightly drier 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

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.310.310.740.78
Feb0.210.260.320.350.930.93
Mar0.350.430.460.521.461.52
Apr0.470.610.560.641.891.95
May0.580.830.640.782.392.45
Jun0.640.990.690.922.852.79
Jul0.641.070.7913.042.85
Aug0.60.950.740.932.792.6
Sep0.50.720.60.742.142.08
Oct0.350.470.460.531.461.49
Nov0.190.220.330.360.930.96
Dec0.120.140.260.270.650.68
Year4.86.846.27.3721.2721.08

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 bottle 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 bottle 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 bottle tree in summer?

In July, established bottle tree in loam needs a deep watering about every 20 days in the Central Valley, about every 27 days on the south coast and about every 22 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 bottle tree need per day?

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

Yes. WUCOLS rates bottle 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, low water in the South Coastal zone, low 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.

Is a bottle tree a good street tree?

It is widely used as a street and screen tree, and it tolerates a range of soils. Its root damage potential is rated moderate, so give it room from paving. The branches are rated medium weak, so prune a young tree to build a sturdy frame.

Are bottle tree seed pods dangerous?

The tree is listed as an irritant, and the pods hold its seeds. Wear gloves when you open pods or rake them up. Fallen pods are dry litter, so keep them off drip emitters and paths.

Does a bottle tree grow in the desert?

Yes. It does well in mild desert climates and is a common street tree in southern Arizona. In the California deserts it needs more summer water than near the coast. Check the soil deeply there in summer.

Do shothole borers attack bottle tree?

UC lists kurrajong as a tree in which invasive shothole borers can breed in California, though not one they usually kill. Look for tiny, round holes in the bark. Healthy trees are attacked too, so watering alone will not prevent it.

How tall does a bottle tree get?

It grows fast and can reach about 40 to 50 feet, often less, with a spread of up to about 30 feet. Its dense crown makes deep shade. Plan the watered area to grow with that crown.

Can a bottle tree grow near the coast?

Yes. It is listed as adapted to the Southern California coast and has moderate salt tolerance. It also grows wild in coastal areas of eastern Australia.

More plant watering guides

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Sources