WateringTimesWatering plan, $19
Zantedeschia aethiopica SHADE IN DESERT, WUCOLS IV

How often to water calla lilies in California

In July in the Central Valley, established calla lilies in loam need a deep watering about every 5 days: about 1.5 gallons each time for a plant 2 feet across, about 1.9 gallons a week. White calla lilies grow from thick rhizomes, carrying broad arrow-shaped leaves and flared white flowers. They need steady moisture while leafy and blooming. Their watering changes when the foliage fades, so check both the clump and its soil before adding more.

PerennialRated for 5 of 6 zones

How often to water calla lilies, month by month

Your city
Plant width
2 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 calla lilies 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 foot 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 1 to 2 inches down over the rhizomes signals that a leafy calla clump needs water
  • Leaves flopping outward over dry soil can indicate thirst, but drooping alone does not establish the cause
  • Flower edges browning early can accompany soil drying during bloom
  • Yellowing across the clump after bloom in inland summer heat can accompany dormancy rather than thirst
  • Mushy rhizomes or collapsing stems over soggy soil can indicate rot around the clump

How to water it

  • Water the whole clump at soil level and soak the top foot of soil around its spreading roots
  • Use drip or a slow hose to deliver water around the rhizomes
  • Mulch with a couple of inches of compost, keeping emerging shoots clear
  • Choose a moist, shaded position and check drainage if stems soften in persistently saturated ground
  • Move emitters outward as rhizomes widen the patch so new growth receives water

Through the seasons

Keep a new leafy clump steadily moist through its first growing season as roots and rhizomes establish. Established white callas can stay green near the coast and grow strongly in cool weather. Inland summer heat can bring yellowing and rest; ease water as foliage dies back. Winter rain can supply coastal and Central Valley plants, while low-desert plants need checks during dry spells. WUCOLS rates callas moderate water on the north-central coast, in the Central Valley, on the south coast, in South Inland and in the low desert. WUCOLS marks them as not suited to the high desert. The WUCOLS entry carries a shade note for the deserts.

In pots

A leafy calla can draw moisture quickly from a small pot in California heat. Check the top inch of mix often while it is growing, and water when that layer dries. Let excess escape through the drainage holes, then empty the saucer. Afternoon shade helps protect containers at hot inland sites. In winter, check whether rain has actually reached the mix. If the top growth dies back, keep the mix barely damp until shoots return.

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
0.711.42.12.90.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.711.42.12.90.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Calla Lilies: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.78–0.78
Feb0.530.650.810.87–0.93
Mar0.871.091.151.3–1.52
Apr1.181.521.41.61–1.95
May1.462.081.611.95–2.45
Jun1.612.481.742.29–2.79
Jul1.612.671.982.51–2.85
Aug1.492.391.862.33–2.6
Sep1.241.81.491.86–2.08
Oct0.871.181.151.33–1.49
Nov0.470.560.840.9–0.96
Dec0.310.340.650.68–0.68
Year1217.1115.518.41–21.08

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 calla lilies. Plants that drink alike can share one valve and one schedule.

DahliasDahlia spp.moderate water, Central Valley2.67 gal/sq ft in JulyFernsNephrolepis cordifolia (SHADE IN DESERT)moderate water, Central Valley2.67 gal/sq ft in JulyDayliliesHemerocallis spp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBegoniasBegonia & ssp. & cvs. (shade in the desert)moderate water, Central Valley2.67 gal/sq ft in JulySageSalvia officinalis and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBicolor MonkshoodAconitum cammarummoderate water, Central Valley2.67 gal/sq ft in JulyGarden MonkshoodAconitum napellusmoderate water, Central Valley2.67 gal/sq ft in JulyCarpet BugleAjuga reptans (shade)moderate water, Central Valley2.67 gal/sq ft in JulySnowdrop WindflowerAnemone sylvestrismoderate water, Central Valley2.67 gal/sq ft in JulyMountain SandwortArenaria montanamoderate water, Central Valley2.67 gal/sq ft in JulySwamp MilkweedAsclepias incarnatamoderate water, Central Valley2.67 gal/sq ft in JulyOrange MilkweedAsclepias tuberosamoderate water, Central Valley2.67 gal/sq ft in JulyGreater MasterwortAstrantia majormoderate water, Central Valley2.67 gal/sq ft in JulyHardy BegoniaBegonia grandismoderate water, Central Valley2.67 gal/sq ft in JulyWax BegoniaBegonia semperflorensmoderate water, Central Valley2.67 gal/sq ft in JulyEnglish DaisyBellis perennismoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

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

AgapanthusAgapanthus orientalislow water, Central Valley1.07 gal/sq ft in JulyGeraniumsPelargonium x hortorum and cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyIrisesIris germanicalow water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyYarrowAchillea millefolium (non-native hybrids)low water, Central Valley1.07 gal/sq ft in JulyMountain AlyssumAlyssum montanumlow water, Central Valley1.07 gal/sq ft in JulySilver SageSalvia argentealow water, Central Valley1.07 gal/sq ft in JulyPurple MulleinVerbascum phoeniceumlow water, Central Valley1.07 gal/sq ft in JulySilvery YarrowAchillea clavennaelow water, Central Valley1.07 gal/sq ft in JulyFern Leaf YarrowAchillea filipendulinalow water, Central Valley1.07 gal/sq ft in JulyCalifornia Native YarrowAchillea millefolium (CA native cultivars)low water, Central Valley1.07 gal/sq ft in JulyWoolly YarrowAchillea tomentosalow water, Central Valley1.07 gal/sq ft in JulyPerennial HollyhockAlcea rosea cvs.low water, Central Valley1.07 gal/sq ft in JulyMountain Lady's MantleAlchemilla alpinalow 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 calla lilies, 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 calla lilies in summer?

In July, established calla lilies in loam need a deep watering about every 5 days in the Central Valley, about every 7 days on the south coast and about every 6 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 do calla lilies need per day?

In July in the Central Valley, established calla lilies need about 0.3 gallons a day for a plant 2 feet across and about 1.1 gallons a day for a plant 4 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 calla lilies change across California?

Yes. WUCOLS rates calla lilies 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, not suited to this region 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.

Can you overwater calla lilies?

White callas tolerate damp ground, including pond edges. A soft, smelly rhizome or collapsing stem still deserves inspection rather than more irrigation. Check drainage when a container remains sodden.

How do I water calla rhizomes after planting?

Water once to settle the soil around a newly planted rhizome. Keep the ground barely damp until shoots appear, then increase moisture as leaves expand. A leafless rhizome needs less water than a flowering clump.

How do I water calla lilies indoors?

Check the mix before following the pattern used for a hot patio. Bright light supports the plant, while a dim room can leave the mix wet longer. Reduce watering when leaves fade after flowering.

Why are my calla leaves turning yellow?

If yellowing begins while white callas are actively growing, inspect the rhizomes before changing irrigation. Remove soft, decaying rhizomes from the clump.

Why are my calla lilies drooping?

Feel the soil and the bases of the stems before watering. Dry ground supports a soaking response, while soft discolored bases in wet soil can indicate rot. Deep shade can also produce long, weak stalks.

More plant watering guides

Massachusetts ManzanitaMountain SandwortTall Oat GrassSwamp MilkweedOrange MilkweedGreater MasterwortJapanese AucubaBrazilian Butterfly Tree

Sources