WateringTimesWatering plan, $19
Hibiscus rosa-sinensis, WUCOLS IV

How often to water hibiscus in California

In July in the Central Valley, established hibiscus in loam needs a deep watering about every 8 days: about 8.8 gallons each time for a plant 4 feet across, about 7.6 gallons a week. Chinese hibiscus is a tropical evergreen shrub that flowers in warm weather with steady soil moisture. Let the ground dry slightly between soakings rather than keeping it saturated. Bud drop can follow moisture swings, but insects, heat and cold can cause the same loss.

ShrubRated for 6 of 6 zones

How often to water hibiscus, month by month

Your city
Plant width
4 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 hibiscus 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 the plant covers, 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 plant width

A shrub with its width marked from one side to the other and the circle under it shaded blue

Measure across the plant, from the tips of the leaves on one side to the tips on the other.

Water the whole area the plant covers, shown in blue. The gallons here cover that area.

A wider plant means more gallons each watering, not more waterings. While it is young, measure again each spring.

How to tell it needs water

  • Soil dry 2 inches down beneath mulch while hibiscus is budding or blooming signals that it needs water
  • Leaves still limp in the morning over dry soil can indicate thirst
  • Yellow buds dropping before opening warrant both a soil check and inspection inside a fallen bud for insects
  • Yellow lower leaves falling while soil stays wet can indicate overwatering or poor drainage
  • Wilting over wet soil can indicate damaged roots, so check drainage before giving hibiscus another soak

How to water it

  • Water around the hibiscus root zone with drip emitters or a slow hose beneath the flowers
  • Soak a foot or more down, then let the top inch or two dry before watering again
  • Spread wood-chip mulch beneath the branches to protect shallow roots, keeping it clear of the stems
  • Use freely draining ground, with a mound or raised bed where heavy clay holds water around the crown
  • Add emitters and widen coverage as the hibiscus branches spread

Through the seasons

Keep a new hibiscus root ball evenly moist through its first summer and expand coverage as roots spread. Established shrubs need deeper soakings with slight drying between them. Water matters most during warm-season growth and flowering. Chinese hibiscus stays evergreen in mild weather and uses less moisture as temperatures fall. Coastal and Central Valley rain can supply winter moisture; check both deserts through dry gaps. WUCOLS rates hibiscus moderate water in all six climate zones. That rating does not describe cold hardiness: a hard freeze can kill Chinese hibiscus, so shelter movable pots before freezing weather.

In pots

Check potted hibiscus daily in summer heat, and more often when a small pot dries quickly in valley or desert sun. Feel the top inch of mix and water when it is dry. Soak until excess leaves the drainage holes, then empty the saucer. Shade a crowded container on hot afternoons and plan repotting for spring. In winter, reduce irrigation as growth slows and move pots under cover or to a bright indoor position before freezing weather.

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

Hibiscus: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.780.740.78
Feb0.530.650.810.870.930.93
Mar0.871.091.151.31.461.52
Apr1.181.521.41.611.891.95
May1.462.081.611.952.392.45
Jun1.612.481.742.292.852.79
Jul1.612.671.982.513.042.85
Aug1.492.391.862.332.792.6
Sep1.241.81.491.862.142.08
Oct0.871.181.151.331.461.49
Nov0.470.560.840.90.930.96
Dec0.310.340.650.680.650.68
Year1217.1115.518.4121.2721.08

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 hibiscus. Plants that drink alike can share one valve and one schedule.

RosesRosa hybrids..bushmoderate water, Central Valley2.67 gal/sq ft in JulyAzaleasRhododendron spp. (CA native and non-native spp.)moderate water, Central Valley2.67 gal/sq ft in JulyCamelliasCamellia japonica (SHADE IN DESERT)moderate water, Central Valley2.67 gal/sq ft in JulyGardeniasGardenia spp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBird of ParadiseStrelitzia reginae (shade in desert)moderate water, Central Valley2.67 gal/sq ft in JulySago PalmCycas revolutamoderate water, Central Valley2.67 gal/sq ft in JulyStar JasmineTrachelospermum jasminoides and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyArborvitaeThuja occidentalis ssp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBambooBambusa spp.moderate water, Central Valley2.67 gal/sq ft in JulyLilacsSyringa hybrids (including Descanso hybrids)moderate water, Central Valley2.67 gal/sq ft in JulySpireaSpiraea spp. (CA native and non native spp.)moderate water, Central Valley2.67 gal/sq ft in JulyButterfly BushBuddleja davidii and hybridsmoderate water, Central Valley2.67 gal/sq ft in JulySageSalvia officinalis and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyRed BuckeyeAesculus paviamoderate water, Central Valley2.67 gal/sq ft in JulyWestern ServiceberryAmelanchier alnifoliamoderate water, Central Valley2.67 gal/sq ft in JulyJapanese AucubaAucuba japonica (SHADE)moderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

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

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 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 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 JulyWild PrivetLigustrum vulgarelow water, Central Valley1.07 gal/sq ft in JulyCoralberrySymphoricarpos orbiculatus (SHADE)low water, Central Valley1.07 gal/sq ft in JulySydney Golden WattleAcacia longifolialow water, Central Valley1.07 gal/sq ft in JulyBlue Leaf WattleAcacia salignalow 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 hibiscus, 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 hibiscus in summer?

In July, established hibiscus 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 hibiscus need per day?

In July in the Central Valley, established hibiscus needs about 1.1 gallons a day for a plant 4 feet across and about 4.3 gallons a day for a plant 8 feet across. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for hibiscus change across California?

Yes. WUCOLS rates hibiscus separately for each of the six California climate zones: moderate 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 water run past my potted hibiscus?

Check whether the root ball has dried and pulled away from the pot wall. Water slowly in more than one pass so moisture reaches the center. A crowded root ball also deserves attention before the next hot season.

How do I water a tree-form hibiscus?

It is the same shrub trained to one trunk. Spread water across the area beneath its leafy head instead of keeping one wet spot against the trunk. Check beneath the mulch while it is growing and flowering.

How do I water hibiscus indoors?

Lower light can slow drying compared with a patio. Give the plant a bright window and check the mix before another soaking. Dry heated air can also drop buds, so extra water in the pot is not always the remedy.

Why does hibiscus wilt every afternoon?

In full sun, leaves can lose moisture faster than roots replace it. Compare their appearance later in the evening and the next morning. If the plant recovers and soil remains damp, another soak is not automatically needed.

Can you overwater hibiscus?

Yes. After cold causes hibiscus leaf loss, its root ball may stay wet much longer. Check that ball before continuing the irrigation used during flowering.

Why are my hibiscus buds dropping?

Check fallen hibiscus buds for feeding scars or thrips. If buds are clean, compare recent temperature changes and root ball moisture before adjusting irrigation.

More plant watering guides

Peach TreesPersimmon TreesGrapevinesArborvitaeBambooCalla LiliesCannasClematis

Sources