WateringTimesWatering plan, $19
Eucalyptus leucoxylon, WUCOLS IV

How often to water white ironbark in California

In July in the Central Valley, established white ironbark 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. White ironbark is a fast-growing evergreen eucalyptus from South Australia and Victoria, 30 to 75 feet tall, often multi-trunked or low branching. Its smooth bark is bright white above, grayish brown and shedding near the base. Small clusters of flowers with showy red, white or pink stamens bloom in winter to early spring, then woody capsules form.

TreeRated for 5 of 6 zones

How often to water white ironbark, 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 white ironbark 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 a foot or more down around a young tree in summer means white ironbark needs a long, slow soak
  • Leaves thinning and branch tips dying in a long drought can signal water stress
  • Oozing spots or holes on the trunk point to borer beetles, which favor stressed trees
  • Yellowing and decline in soggy ground point to too much water

How to water it

  • Water a young tree deeply and infrequently so moisture reaches a foot or more down
  • Use drip emitters or a slow hose so water soaks in rather than runs off
  • Keep a steady routine once you start, since a sudden stop stresses the tree
  • Plant in sun to part shade in well-drained soil
  • Remove and properly handle dead limbs and cut wood

Through the seasons

Water a young tree regularly through its first summers. Once established, it needs only infrequent, deep watering, given slowly so it reaches a foot or more down. Avoid suddenly cutting off water to a tree used to irrigation, since stressed eucalyptus attract borer beetles. It blooms from winter into early spring. WUCOLS rates white ironbark low water on the north-central coast, in the Central Valley, on the south coast and in South Inland. The low desert carries a moderate water rating. WUCOLS marks it as not suited to the high desert.

In pots

White ironbark grows too fast and large for a pot beyond its first year, so a container is only a holding stage. Keep a young tree in a deep container with a well-drained mix. Water when the top few inches dry, soaking until it drains from the base. In summer, check every few days. Do not let it sit in water. Plant it out while it is small and the roots are still easy to spread.

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
0.711.42.12.90.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.711.42.12.90.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

White Ironbark: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.310.31–0.78
Feb0.210.260.320.35–0.93
Mar0.350.430.460.52–1.52
Apr0.470.610.560.64–1.95
May0.580.830.640.78–2.45
Jun0.640.990.690.92–2.79
Jul0.641.070.791–2.85
Aug0.60.950.740.93–2.6
Sep0.50.720.60.74–2.08
Oct0.350.470.460.53–1.49
Nov0.190.220.330.36–0.96
Dec0.120.140.260.27–0.68
Year4.86.846.27.37–21.08

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 white ironbark. 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 white ironbark, 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 white ironbark in summer?

In July, established white ironbark 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 white ironbark need per day?

In July in the Central Valley, established white ironbark 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 white ironbark change across California?

Yes. WUCOLS rates white ironbark 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, not suited to this region 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 keep borers out of white ironbark?

Longhorned borers mostly attack stressed or damaged eucalyptus. Water deeply in long dry spells and avoid sudden stops in irrigation. Do not store fresh-cut eucalyptus wood near living trees.

How big does white ironbark get?

It grows fast to 30 to 75 feet tall and 20 to 50 feet wide. It is often multi-trunked. Give it plenty of room.

When does white ironbark bloom?

Flowers open from winter into early spring. Stamens may be red, white or pink. Woody seed capsules follow.

Why is white ironbark bark peeling?

The lower trunk sheds grayish brown bark. Above, the bark is smooth and bright white. Shedding is normal.

How should I water an established eucalyptus?

Water infrequently but deeply, so moisture reaches a foot or more down. Slow drip works best. Keep the routine steady through summer.

More plant watering guides

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Sources