WateringTimesWatering plan, $19
Corymbia maculata (Eucalyptus maculata), WUCOLS IV

How often to water spotted gum in California

In July on the north-central coast, established spotted gum in loam needs a deep soak only about once a month or less: about 55 gallons each time under a 10 foot canopy. Spotted gum is a tall, long-lived eucalyptus from coastal forests of eastern Australia, often 60 to 100 feet tall with a straight trunk. Its smooth bark flakes in small patches each summer, leaving a mottled pattern of gray, pink and blue-gray. Clusters of white flowers appear from early winter into spring. It needs little summer water near the coast once established.

TreeRated for 4 of 6 zones

How often to water spotted gum, 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 spotted gum 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

  • Spotted gum leaves drooping on a young tree while the soil is dry deep down mean it needs a soak
  • Bark flaking in patches in summer is normal, not stress
  • Yellowing leaves on soil that stays wet point to overwatering
  • Leaf damage after a freeze below about 20 degrees F points to cold

How to water it

  • Water a young tree deeply across the root zone, then let the soil dry before the next soak
  • Plant in full sun in well-drained soil
  • Taper to little summer water once it is established near the coast
  • Give steadier deep soaks in South Inland and the low desert
  • Set it back from the first line of ocean exposure

Through the seasons

Water a young tree regularly through its first summer. Once established, it needs little summer water in coastal gardens. Hotter inland and desert gardens call for steadier deep soaks. It is evergreen, sheds bark in summer and flowers from early winter into spring. WUCOLS rates spotted gum low water on the north-central coast and on the south coast. WUCOLS rates it moderate water in South Inland and in the low desert. WUCOLS marks it as not suited to the Central Valley or the high desert.

In pots

Spotted gum grows into a very large tree, so a pot is only a short stop for a young plant. Use a fast-draining mix in a deep container. Water when the top couple of inches dry, then let it drain. In summer, check every couple of days. Empty the saucer after each watering. Plant it out while small, before roots circle. In winter, water only when the mix dries.

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

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

Monthly water need by climate zone

Spotted Gum: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.15–0.310.78–0.78
Feb0.21–0.320.87–0.93
Mar0.35–0.461.3–1.52
Apr0.47–0.561.61–1.95
May0.58–0.641.95–2.45
Jun0.64–0.692.29–2.79
Jul0.64–0.792.51–2.85
Aug0.6–0.742.33–2.6
Sep0.5–0.61.86–2.08
Oct0.35–0.461.33–1.49
Nov0.19–0.330.9–0.96
Dec0.12–0.260.68–0.68
Year4.8–6.218.41–21.08

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 not suited to this region in the Central Valley, like spotted gum. 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 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 ratingRainbow EucalyptusEucalyptus degluptanot 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 spotted gum, 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 spotted gum in summer?

In July, established spotted gum in loam needs a deep watering about every 27 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 spotted gum need per day?

In July on the north-central coast, established spotted gum needs about 1.6 gallons a day under a 10 foot canopy and about 6.5 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 spotted gum change across California?

Yes. WUCOLS rates spotted gum separately for each of the six California climate zones: low water in the North-Central Coastal zone, not suited to this region in the Central Valley zone, low 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, 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 spotted gum bark peeling?

The smooth bark flakes off in small patches in summer. The mottled old bark contrasts with the paler new bark. That patchwork is its best feature.

How tall does spotted gum get?

It typically reaches 60 to 100 feet. It needs a large lot. Plant it well away from buildings.

How is spotted gum different from lemon-scented gum?

The two are close relatives. Spotted gum has mottled, often dimpled bark and larger, darker leaves. Its leaves lack the lemon scent.

How cold can spotted gum take?

It is hardy to about 19 to 23 degrees F. Hard freezes damage it. Mild coastal and southern gardens suit it.

Can spotted gum grow by the beach?

It suits coastal gardens set back from first exposure. Direct salt wind is too much. Plant it a little inland of the surf.

More plant watering guides

Queensland Bottle TreeSaguaroMoreton Bay ChestnutRed Flowering GumDragon TreeCandelabra TreeMilk BushBoojum

Sources