WateringTimesWatering plan, $19
Hibiscus syriacus, WUCOLS IV

How often to water rose of Sharon in California

In July in the Central Valley, established rose of Sharon 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. Rose of Sharon is an upright deciduous shrub, 8 to 12 feet tall, that can also be trained as a small tree. Its leaves arrive in late spring, and large single or double flowers open in succession from midsummer into fall, each lasting one day. It prefers moist, well-drained soil and adapts to most ground short of very wet or very dry.

ShrubRated for 4 of 6 zones

How often to water rose of Sharon, 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 rose of Sharon 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

  • During bloom, soil dry 3 to 4 inches down beneath the outer branches signals that rose of Sharon needs a soak
  • Leaves still drooping in the evening after a hot day can indicate thirst when the ground is dry
  • Bare branches in early spring are normal for this late leafing shrub and do not call for extra water
  • Yellow leaves over soggy soil can indicate overwatering, since it dislikes ground that stays very wet
  • A steady drop of spent flowers is normal, because each bloom lasts only a day

How to water it

  • Water rose of Sharon in a broad band beneath its outer branches, not just at the stems
  • Soak the soil about 12 inches deep, and wait for the top few inches to dry out before the next soak
  • Use drip or a soaker line that delivers water slowly into the soil
  • Spread a few inches of mulch over the root area to even out moisture through the summer bloom
  • Widen the watered band as the shrub fills out, and pull unwanted seedlings that sprout beneath it

Through the seasons

Give a new rose of Sharon steady moisture through its first summer while roots spread. WUCOLS rates it low water on the north-central coast and moderate water in the Central Valley, on the south coast and in South Inland. It marks the high desert and the low desert as not suited to it. Established shrubs tolerate some neglect, yet they grow best with deep soakings through bloom. Leaves appear late in spring, and flowers run from midsummer into fall, the stretch when irrigation matters most. After leaf fall the shrub is dormant, and winter rain usually covers it on the coast and in the Central Valley.

In pots

Rose of Sharon can live in a large container while young or when trained as a small standard. Use a wide pot with drainage holes and a loam based mix. During summer bloom, check the mix 2 inches down every few days and water when that layer is dry. Water until excess drains, then empty the saucer. After leaf fall, water sparingly, since the leafless shrub uses little. Do not let the mix dry out completely before new leaves return in late spring.

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
0.671.32.02.70.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.671.32.02.70.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Rose of Sharon: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.40.780.78––
Feb0.210.650.810.87––
Mar0.351.091.151.3––
Apr0.471.521.41.61––
May0.582.081.611.95––
Jun0.642.481.742.29––
Jul0.642.671.982.51––
Aug0.62.391.862.33––
Sep0.51.81.491.86––
Oct0.351.181.151.33––
Nov0.190.560.840.9––
Dec0.120.340.650.68––
Year4.817.1115.518.41––

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 moderate water in the Central Valley, like rose of Sharon. 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 JulyHibiscusHibiscus rosa-sinensismoderate 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 July

Similar plants that need less water 16

Rated lower than rose of Sharon 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 rose of Sharon, 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 rose of Sharon in summer?

In July, established rose of Sharon 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 rose of Sharon need per day?

In July in the Central Valley, established rose of Sharon 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 rose of Sharon change across California?

Yes. WUCOLS rates rose of Sharon 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, 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 does my rose of Sharon leaf out so late?

Its leaves naturally appear in late spring. Bare stems in early spring are normal. Scratch a twig to look for green wood before assuming the shrub is dead or dry.

Why are rose of Sharon seedlings coming up everywhere?

It self-sows freely and can become invasive. Pull seedlings while they are small. The seed capsules persist through winter, so clearing them reduces the spread.

When should I prune rose of Sharon?

Prune in spring. Flowers form on new growth, and spring pruning encourages more and larger blooms. Keep the soil moist as the new shoots develop.

Can rose of Sharon grow near the coast?

Yes. It is moderately salt tolerant and is often planted in coastal gardens. Give it full sun and well-drained soil there.

Can you overwater rose of Sharon?

Yes. It handles soil that is occasionally wet but not ground that stays waterlogged. Let the upper soil dry between soakings, especially in heavy clay.

More plant watering guides

Little Leaf LindenChinese ToonPurple Heart SpiderwortChinese Tallow TreeAmerican ElmGarden ValerianWavy-Leafed MulleinVeronica

Sources