WateringTimesWatering plan, $19
Eucalyptus cladocalyx, WUCOLS IV

How often to water sugar gum in California

In July on the north-central coast, established sugar gum in loam needs a deep soak only about once a month or less: about 55 gallons each time under a 10 foot canopy. Sugar gum is a tall, fast-growing evergreen eucalyptus from South Australia. As it grows, the lower branches fall away and leave a long, clean trunk with shedding bark. Creamy flowers open in summer. An established tree gets by on little water, but a drought-stressed one draws borers, so deep soaks spaced well apart serve it better than frequent light ones.

TreeRated for 3 of 6 zones

How often to water sugar 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 sugar 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

  • Soil dry a foot down under the outer canopy of a young sugar gum during a long dry spell means it is ready for a deep soak
  • Leaves that discolor and wilt while limbs die back can mean borers have found a water-stressed tree
  • Holes in the bark with stains or oozing liquid on the trunk or limbs point to longhorned borers, which favor stressed trees
  • Ground that stays soggy around the trunk base after watering is a warning, since eucalyptus is prone to Armillaria and Phytophthora root rots
  • Shedding bark and dropped lower branches are normal for sugar gum and do not signal thirst

How to water it

  • Apply water to the ground below the outer edge of the canopy rather than close to the trunk
  • Run drip emitters slowly for long sessions so the water reaches a foot or more into the soil
  • Skip frequent shallow watering of the kind lawns get, which favors root disease in eucalyptus
  • Keep the root crown out of standing water, and plant in clay, loam or sand that drains freely
  • Move the emitters outward as the crown widens so the wet band stays under the canopy edge

Through the seasons

Give a new sugar gum deep, slow soakings through its first summers, widening the wet area as roots spread. Established trees benefit from a deep soak during long dry periods, especially after a winter with below-normal rain. Sugar gum stays evergreen and blooms in summer, when heat stress and borer activity peak. Winter rain covers the cool months on the north-central coast and the south coast. In South Inland, check the soil a foot down during dry winter spells. WUCOLS rates sugar gum low water on the north-central coast, on the south coast and in South Inland. WUCOLS marks it as not suited to the Central Valley, the high desert or the low desert.

In pots

Sugar gum grows into a very large tree, so a pot only holds it while it is young, before planting out. Check a nursery can 2 inches down every few days in summer, and daily in South Inland heat. Water until it runs from the drainage holes, then empty the saucer so the roots do not sit in water. A dark can on hot paving dries and heats fast, so shade the container itself. In winter the young tree grows slowly, so let the mix dry a little more between soakings.

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

WUCOLS lists Sugar 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

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.15–0.310.31––
Feb0.21–0.320.35––
Mar0.35–0.460.52––
Apr0.47–0.560.64––
May0.58–0.640.78––
Jun0.64–0.690.92––
Jul0.64–0.791––
Aug0.6–0.740.93––
Sep0.5–0.60.74––
Oct0.35–0.460.53––
Nov0.19–0.330.36––
Dec0.12–0.260.27––
Year4.8–6.27.37––

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 sugar 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 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 ratingRainbow EucalyptusEucalyptus degluptanot rated, Central Valleyno Central Valley ratingRoxburgh FigFicus auriculatanot rated, Central Valleyno Central Valley ratingIndian BanyanFicus benghalensisnot 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 sugar 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 sugar gum in summer?

In July, established sugar gum in loam needs a deep watering 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 sugar gum need per day?

In July on the north-central coast, established sugar 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 sugar gum change across California?

Yes. WUCOLS rates sugar 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, low 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 sugar gum shedding bark?

Shedding bark is normal for this eucalyptus. Its lower branches also fall away as it grows, which leaves a tall, clean trunk. Neither one is a sign of thirst on its own.

Does sugar gum get eucalyptus borers?

It can, but UC research lists sugar gum among the species more resistant to the common eucalyptus longhorned borer. These beetles favor trees under drought stress. A deep soak during a long dry spell keeps the tree less attractive to them.

Should I stop watering an older sugar gum?

Not suddenly. A tree that has been watered regularly becomes stressed when irrigation stops, and that stress invites borer attack. If you cut back, do it gradually and avoid long gaps in summer.

When should I prune a sugar gum?

Do routine pruning in December and January, when adult borer beetles are not flying. Freshly cut wood attracts them, and adults emerge from spring through fall. Remove infested limbs right away at any time of year.

What do I do with cut sugar gum wood?

Fresh eucalyptus wood draws egg-laying borers until it dries. Chip it, or split it and strip the bark so it dries faster. Chipped eucalyptus makes a good mulch.

Can sugar gum spread on its own?

Yes. It has gone wild in disturbed coastal areas of California, and its tiny seeds travel on the wind. Pull seedlings that come up nearby, and think twice before planting it next to open land.

More plant watering guides

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Sources