WateringTimesWatering plan, $19
Leptospermum scoparium, WUCOLS IV

How often to water New Zealand tea tree in California

In July in the Central Valley, established New Zealand tea tree 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. New Zealand tea tree is an upright, twiggy evergreen shrub with small, needle-like leaves. It puts on a heavy show of five-petaled flowers in white, pink or red. Most garden selections come from New Zealand and grow into dense shrubs, some 8 to 10 feet tall. It likes full sun, seaside air and well-drained, slightly acid soil, and young plants do not forgive drying out.

ShrubTreeRated for 4 of 6 zones

How often to water New Zealand tea tree, 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 New Zealand tea tree 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 several inches down around a young plant calls for water right away, since tea tree is unforgiving of drying out
  • Needles browning after a dry spell show the roots went too dry for this shrub
  • Yellowing and dieback in soggy, poorly drained soil point to too much water
  • A sudden decline of an established shrub can point to Armillaria root rot rather than thirst
  • Pale, yellowing leaves in alkaline ground point to a soil problem, since it prefers slightly acid soil

How to water it

  • Water young plants deeply and regularly until established, never letting the root ball dry out
  • Once established, soak about a foot down and let the upper soil dry before watering again
  • Plant in full sun in well-drained, slightly acid soil, near the coast if you can
  • Prune occasionally to thin and shape the shrub
  • Widen the watered area as the shrub fills out

Through the seasons

Water new plants regularly through their first summer or two, since they do not forgive drying out. Established shrubs need less, especially in the Central Valley and on the south coast. Many selections flower heavily in spring, and some bloom again in fall. Winter rain usually covers it on the coast and in the Central Valley. WUCOLS rates New Zealand tea tree moderate water on the north-central coast and in South Inland. It rates low water in the Central Valley and on the south coast. WUCOLS marks it as not suited to the high desert or the low desert.

In pots

A young New Zealand tea tree can grow in a large container in full sun for a few years. Pick a pot with open drainage holes and fill it with a well-drained, slightly acid potting mix. When the weather turns hot, test the mix daily with a finger and water as soon as the top inch dries. Never let the whole root ball go dry. Let water drain through, then empty the saucer. In winter, water less but keep the mix lightly moist.

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
0.631.31.92.50.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.631.31.92.50.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

New Zealand Tea Tree: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.160.310.78––
Feb0.530.260.320.87––
Mar0.870.430.461.3––
Apr1.180.610.561.61––
May1.460.830.641.95––
Jun1.610.990.692.29––
Jul1.611.070.792.51––
Aug1.490.950.742.33––
Sep1.240.720.61.86––
Oct0.870.470.461.33––
Nov0.470.220.330.9––
Dec0.310.140.260.68––
Year126.846.218.41––

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 low water in the Central Valley, like New Zealand tea tree. Plants that drink alike can share one valve and one schedule.

LavenderLavandula spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRosemaryRosmarinus officinalislow water, Central Valley1.07 gal/sq ft in JulyBougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyOlive 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 JulyLantanaLantana camara ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria 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 JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySagebrushArtemisia spp. (shrubby)low 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 New Zealand tea tree, 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 New Zealand tea tree in summer?

In July, established New Zealand tea tree 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 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 New Zealand tea tree need per day?

In July in the Central Valley, established New Zealand tea tree 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 New Zealand tea tree change across California?

Yes. WUCOLS rates New Zealand tea tree separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, low water 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, 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 did my tea tree die suddenly?

Young plants often fail after the root ball dries out once, since tea tree is unforgiving of drought before it is established. In older shrubs, Armillaria root rot can cause a sudden decline. Check soil moisture first.

Can New Zealand tea tree grow near the ocean?

Yes. It does well in seacoast conditions and full sun. Coastal plantings still need regular water until established.

Should I prune New Zealand tea tree?

Prune occasionally to thin and shape the shrub. Long branches also make good cut flowers.

How cold hardy is New Zealand tea tree?

It is hardy to about 20 degrees F. Colder snaps can damage it, so protect young plants during a freeze.

Can you overwater New Zealand tea tree?

Yes. It needs well-drained soil, and soggy ground leads to decline. The trick is balance: soak deeply, let the top dry, and never let a young plant dry out completely.

More plant watering guides

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Sources