WateringTimesWatering plan, $19
Eucalyptus deglupta, WUCOLS IV

How often to water rainbow eucalyptus in California

In July on the south coast, established rainbow eucalyptus in loam needs a deep watering about every 11 days: about 55 gallons each time under a 10 foot canopy, about 35 gallons a week. Rainbow eucalyptus, also called Mindanao gum, is a fast-growing tropical eucalyptus from the Philippines, Indonesia and New Guinea. Its smooth bark peels in summer to reveal spectacular multicolored streaks. Unlike many eucalyptus species, it needs ample water to thrive and does not take drought well.

TreeRated for 2 of 6 zones

How often to water rainbow eucalyptus, 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 rainbow eucalyptus 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 to 6 inches down under the canopy in summer signals that a rainbow eucalyptus needs a deep soak
  • Leaves wilting or dropping during a dry spell point to drought stress, which this tropical tree handles poorly
  • Holes in the bark with oozing sap point to borers, which go after stressed eucalyptus
  • Wilting over wet soil, or honey-colored mushrooms at the trunk base, warns of root rot in poorly drained ground
  • Bark peeling away in long strips each summer is normal and shows the fresh color beneath

How to water it

  • Run drip emitters or a slow hose over a young tree's root ball and the soil just past it
  • Wet the soil to a depth of about 18 inches, and soak again once the top several inches have dried
  • Plant in loam or sandy soil that drains well, never in a low spot where water stands
  • Keep the trunk base dry, placing water under the outer canopy as the tree grows
  • Widen the watered zone as the canopy spreads, since the tree can reach 60 feet across

Through the seasons

Give a newly planted rainbow eucalyptus deep, regular soakings through its first summers while roots spread. Established trees keep needing steady water through the dry months, since this tropical species needs ample water to thrive. The bark sheds in summer, and growth runs fast in warm weather. Coastal winter rain usually does the job from late fall into spring; farther inland, check the soil whenever a dry spell stretches on. For the south coast and South Inland, WUCOLS gives rainbow eucalyptus a moderate water rating. It is marked not suited to the north-central coast, the Central Valley, the high desert and the low desert.

In pots

Rainbow eucalyptus grows fast, so it suits a container only while young. Use a large, deep pot with a free-draining mix. Check the mix 2 inches down every few days in summer, and soak it until water drains from the holes. Empty the saucer so the roots never sit in water. Plant it out before the roots circle, and keep watering in winter dry spells, since this tropical evergreen keeps its leaves all year.

1 Your climate zone six WUCOLS zones, each from its own reference city
Not ratedWUCOLS does not rate Rainbow Eucalyptus for the Central Valley zone
A year
no figure
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses

WUCOLS lists Rainbow Eucalyptus as not suited to this region for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Rainbow Eucalyptus: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan––0.780.78––
Feb––0.810.87––
Mar––1.151.3––
Apr––1.41.61––
May––1.611.95––
Jun––1.742.29––
Jul––1.982.51––
Aug––1.862.33––
Sep––1.491.86––
Oct––1.151.33––
Nov––0.840.9––
Dec––0.650.68––
Year––15.518.41––

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 not suited to this region in the Central Valley, like rainbow eucalyptus. Plants that drink alike can share one valve and one schedule.

Sugar MapleAcer saccharumnot rated, Central Valleyno Central Valley ratingQueensland KauriAgathis robustanot rated, Central Valleyno Central Valley ratingCherimoyaAnnona cherimolanot rated, Central Valleyno Central Valley ratingPurple Orchid TreeBauhinia variegata (purpurea)not rated, Central Valleyno Central Valley ratingToogBischofia javanicanot rated, Central Valleyno Central Valley ratingClustered Fishtail PalmCaryota mitisnot rated, Central Valleyno Central Valley ratingWhite SapoteCasimiroa edulisnot rated, Central Valleyno Central Valley ratingFilbertCorylus maximanot rated, Central Valleyno Central Valley ratingSpotted GumCorymbia maculata (Eucalyptus maculata)not rated, Central Valleyno Central Valley ratingDove TreeDavidia involucratanot rated, Central Valleyno Central Valley ratingRoyal PoincianaDelonix regianot rated, Central Valleyno Central Valley ratingTriangle PalmDypsis decaryinot rated, Central Valleyno Central Valley ratingMountain White GumEucalyptus dalrympleananot rated, Central Valleyno Central Valley ratingRoxburgh FigFicus auriculatanot rated, Central Valleyno Central Valley ratingIndian BanyanFicus benghalensisnot rated, Central Valleyno Central Valley ratingWeeping Chinese BanyanFicus benjaminanot rated, Central Valleyno Central Valley rating
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes rainbow eucalyptus, 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 rainbow eucalyptus in summer?

In July, established rainbow eucalyptus in loam needs a deep watering 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 rainbow eucalyptus need per day?

In July on the south coast, established rainbow eucalyptus needs about 5.0 gallons a day under a 10 foot canopy and about 20 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 rainbow eucalyptus change across California?

Yes. WUCOLS rates rainbow eucalyptus separately for each of the six California climate zones: not suited to this region in the North-Central Coastal zone, not suited to this region in the Central Valley zone, moderate water in the South Coastal zone, moderate water in the South Inland zone, not suited to this region 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.

Why is my rainbow eucalyptus bark peeling?

Peeling is normal. The smooth bark sheds in summer and exposes fresh, multicolored bark beneath. It is not a sign of thirst or disease.

Is rainbow eucalyptus drought tolerant?

No. Unlike many eucalyptus, it needs ample water to thrive. Plan on deep soakings through the dry season, with the trunk base kept dry.

How big does rainbow eucalyptus get?

In California landscapes it can reach about 60 feet tall and wide, and it grows fast. Plant it well away from buildings and paving, since its roots have a moderate chance of lifting hardscape.

Do borers attack rainbow eucalyptus?

Beetle borers are a known pest, and borers favor eucalyptus stressed by drought. Keeping the tree evenly watered through summer lowers that risk.

Is rainbow eucalyptus the same as Mindanao gum?

Yes, Mindanao gum is another common name. Some experts split it into two species and treat most trees grown in California as Eucalyptus binacag. Care is the same either way.

More plant watering guides

Yellow Bell BauhiniaPurple Orchid TreeToogMagic FlowerClustered Fishtail PalmWhite SapoteHawaiian TiFilbert

Sources