WateringTimesWatering plan, $19
Castanospermum australe, WUCOLS IV

How often to water Moreton Bay chestnut in California

In July on the north-central coast, established Moreton Bay chestnut in loam needs a deep soak only about once a month or less: about 55 gallons each time under a 10 foot canopy. Moreton Bay chestnut is a slow-growing evergreen tree from coastal rainforests and stream banks of eastern Australia. Its large, glossy leaves are divided into leathery, dark green leaflets. Red and yellow pea flowers bloom in summer, best where summers are warm. Thick seed pods follow, holding large, chestnut-like seeds that are poisonous raw.

TreeRated for 3 of 6 zones

How often to water Moreton Bay chestnut, 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 Moreton Bay chestnut 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

  • Glossy leaflets on Moreton Bay chestnut dulling or drooping while the soil is dry deep down mean it needs a soak
  • Leaves yellowing and dropping in soggy soil point to overwatering
  • Sparse summer bloom near the coast can reflect cool weather, not thirst
  • Leaf scorch after a freeze below about 25 degrees F points to cold damage

How to water it

  • Water deeply at the edge of the canopy, then let the soil dry before the next soak
  • Plant in full sun to light shade in well-drained soil
  • Keep it away from old clay sewer lines and septic leach fields
  • Give occasional deep summer soaks in the north and steady deep soaks in the south
  • Widen the watered area as the canopy spreads

Through the seasons

Water a young tree regularly through its first few summers. Once established, it needs only occasional summer water on the north-central coast and steady deep soaks in the south. It is evergreen and flowers in summer. The pods dry in fall and split to drop seeds in early winter. WUCOLS rates Moreton Bay chestnut low water on the north-central coast. The south coast and South Inland carry the same moderate water rating. WUCOLS marks it as not suited to the Central Valley, the high desert or the low desert.

In pots

Moreton Bay chestnut is a large tree, but seedlings are sometimes grown in pots as a curiosity, even indoors in bright light. Use a well-drained mix in a deep pot. Water when the top couple of inches dry, until it drains out. Outdoors in summer, check every few days. Empty the saucer. Plant it out before roots circle the pot. Keep pots above freezing in winter and water sparingly.

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

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

Monthly water need by climate zone

Moreton Bay Chestnut: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.15–0.780.78––
Feb0.21–0.810.87––
Mar0.35–1.151.3––
Apr0.47–1.41.61––
May0.58–1.611.95––
Jun0.64–1.742.29––
Jul0.64–1.982.51––
Aug0.6–1.862.33––
Sep0.5–1.491.86––
Oct0.35–1.151.33––
Nov0.19–0.840.9––
Dec0.12–0.650.68––
Year4.8–15.518.41––

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 Moreton Bay chestnut. 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 Moreton Bay chestnut, 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 Moreton Bay chestnut in summer?

In July, established Moreton Bay chestnut 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 Moreton Bay chestnut need per day?

In July on the north-central coast, established Moreton Bay chestnut 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 Moreton Bay chestnut change across California?

Yes. WUCOLS rates Moreton Bay chestnut 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, 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.

Are Moreton Bay chestnut seeds edible?

No, the raw seeds are poisonous. Keep children and pets away from fallen seeds. Pick them up after the pods split in early winter.

Will Moreton Bay chestnut roots lift paving?

Its roots do not lift pavement, so it works as a patio or street tree. They do seek water. Keep it away from old leaky sewer lines and septic fields.

Does Moreton Bay chestnut attract hummingbirds?

Yes, the flowers make plenty of nectar and draw hummingbirds. Bloom is best with summer heat. Coastal trees still flower in many years.

How big does Moreton Bay chestnut get?

It grows slowly to about 25 to 40 feet tall in gardens. Old trees can pass 45 feet. The crown is rounded to flat-topped.

How cold can Moreton Bay chestnut take?

It is hardy to about 25 degrees F. Young trees need frost protection. Hard freezes in colder valleys damage it.

More plant watering guides

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Sources