WateringTimesWatering plan, $19
Pittosporum tobira and cvs., WUCOLS IV

How often to water mock orange in California

In July in the Central Valley, established mock orange in loam needs a deep watering about every 8 days: about 55 gallons each time under a 10 foot canopy, about 47 gallons a week. This mock orange is Pittosporum tobira, also called tobira, a dense evergreen shrub or small tree with leathery, glossy leaves. Clusters of small white flowers in spring smell like orange blossoms and age to creamy yellow. Seed capsules later split to show sticky orange seeds. It tolerates salt spray and heat, but root rot is likely in wet, poorly drained soil.

ShrubTreeRated for 6 of 6 zones

How often to water mock orange, 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 mock orange 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 inches down at the drip line in summer means mock orange is ready for a deep soak
  • Leaves losing their gloss and curling slightly in an inland heat wave can show the roots are dry
  • Yellowing leaves and thinning branches in soil that stays wet point to root rot
  • Sticky leaves, sooty mold or cottony clusters point to aphids, scale or mealybugs rather than thirst
  • Leaf, flower and fruit drop under the shrub is normal litter, not a water signal

How to water it

  • Water mock orange along its drip line with drip or a soaker rather than overhead spray
  • Soak about 12 inches deep, then let the top several inches dry before the next watering
  • Plant in well-drained soil, avoiding low, wet spots where root rot can start
  • Mulch beneath the branches with bark, leaving the main stems clear
  • Shift emitters outward as the shrub broadens, and space them along both sides of a hedge

Through the seasons

Water a new mock orange regularly through its first summer while roots spread beyond the nursery ball. Established shrubs stay evergreen and take deeper, less frequent soakings. Fragrant flowers open in spring, and seed capsules ripen later and split to release sticky orange seeds. Irrigation matters most from late spring through fall. Coastal and Central Valley winter rain usually covers the cool months. On the north-central coast, WUCOLS rates mock orange low water. The Central Valley, the south coast, South Inland, the high desert and the low desert all carry a moderate water rating.

In pots

Dwarf forms such as 'Wheeler's Dwarf' stay 2 to 3 feet tall, so they suit pots and planters for years. Use a container with drainage holes and a free-draining mix. In hot weather, check the mix 2 inches down every few days, and water once it has dried there. Pour out the saucer after watering so roots never stand in water. In winter, water only when the top inches are dry, since soggy mix invites root rot.

1 Your climate zone six WUCOLS zones, each from its own reference city
2.67gal per sq ft in JulyModerate water use in the Central Valley zone
A year
17.11 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.761.52.33.00.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.761.52.33.00.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Mock Orange: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.40.780.780.740.78
Feb0.210.650.810.870.930.93
Mar0.351.091.151.31.461.52
Apr0.471.521.41.611.891.95
May0.582.081.611.952.392.45
Jun0.642.481.742.292.852.79
Jul0.642.671.982.513.042.85
Aug0.62.391.862.332.792.6
Sep0.51.81.491.862.142.08
Oct0.351.181.151.331.461.49
Nov0.190.560.840.90.930.96
Dec0.120.340.650.680.650.68
Year4.817.1115.518.4121.2721.08

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 moderate water in the Central Valley, like mock orange. Plants that drink alike can share one valve and one schedule.

Similar plants that need less water 16

Rated lower than mock orange in the Central Valley. Worth a look for a new bed or a lawn replacement.

Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes mock orange, 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 mock orange in summer?

In July, established mock orange in loam needs a deep watering about every 8 days in the Central Valley, 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 mock orange need per day?

In July in the Central Valley, established mock orange needs about 6.8 gallons a day under a 10 foot canopy and about 27 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 mock orange change across California?

Yes. WUCOLS rates mock orange separately for each of the six California climate zones: low water in the North-Central Coastal zone, moderate water in the Central Valley zone, moderate water in the South Coastal zone, moderate water in the South Inland zone, moderate water 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 does my mock orange smell like orange blossoms?

Its small spring flowers are strongly fragrant, with a scent like sweet orange blossom. They open white and turn yellow after pollination. The fragrance has no link to watering.

Can mock orange grow near the beach?

Yes. It tolerates salt spray and suits sandy coastal sites. Sandy soil drains fast, so check moisture there before each soak.

Why is my mock orange dying in clay soil?

Wet, poorly drained soil invites root rot in this shrub. Water less often and improve drainage, or replant on a raised mound. Heavy clay that stays soggy after rain is the usual culprit.

Do deer eat mock orange?

Yes, deer frequently damage it. Browsed shoots are not a sign of thirst. Protect young plants until they are large enough to withstand feeding.

How big does mock orange get?

The species grows roughly 8 to 15 feet tall and 8 to 10 feet wide, so it works as a screen. Dwarf forms stay 2 to 3 feet. A large shrub needs emitters spread over a wider area.

More plant watering guides

Sources