WateringTimesWatering plan, $19
Zephyranthes candida, WUCOLS IV

How often to water white rain lily in California

In July in the Central Valley, established white rain lily needs about 0.8 gallons a week for a plant 2 feet across. White rain lily is a small bulb from South American marshes and riverbanks. It forms clumps of glossy, rushlike leaves about a foot tall. White, crocus-like flowers with yellow stamens open in late summer and fall, often right after a rain. It handles damp soil and short dry spells alike, and a slight drying between soakings helps it flower.

BulbUC Arboretum All-StarRated for 6 of 6 zones

How often to water white rain lily, 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 white rain lily and the rest of your yard, on the days your water supplier allows.Get the plan for $19

How this is worked out: the plant’s WUCOLS rating times your city’s climate for the month, over the area the plant covers. 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 inside the clump in summer means the bulbs are ready for a thorough soak
  • A flush of white flowers soon after a rain or a deep soak is this lily's normal response, not a sign of trouble
  • Plenty of leaves but few flowers over soil that never dries can mean the clump needs a slight dry spell between soakings
  • Leaves dying back in a hot inland summer can be sun stress, so check the soil and give the clump afternoon shade
  • Ragged holes in the leaves and silvery slime trails point to snails and slugs, which favor damp beds

How to water it

  • Water at the base of the white rain lily clump with drip or a slow hose, wetting the soil around and below the bulbs
  • Soak the bed, then let the top inch or two dry slightly before watering again, which helps the bulbs set flowers
  • Water in the morning, or switch to drip, where snails and slugs hide among the leaves
  • Plant in humusy, well-drained soil, or set clumps at the edge of a pond where the roots stay damp
  • Widen the watered area as offsets spread the clump outward, and divide crowded clumps in spring

Through the seasons

Keep newly planted bulbs lightly moist while leaves and roots grow. Established clumps do best with a slight drying between soakings. Summer and the late summer to fall bloom are when irrigation matters most. The leaves stay green through mild winters, while a hard freeze knocks them down and the bulbs regrow. Winter rain covers the cool months on the north-central coast, the south coast and in the Central Valley. WUCOLS rates white rain lily moderate water on the north-central coast, the south coast and the low desert. It rates low water in the Central Valley, South Inland and the high desert. In both deserts, check the soil during long dry winter spells.

In pots

White rain lily suits a patio pot, where its late summer flowers sit close to eye level. Check the mix about an inch down every few days in summer, and daily in valley or desert heat. Water until it drains from the holes, then empty the saucer. Letting the mix dry slightly before the next deep watering helps the bulbs flower. In winter, keep the mix barely moist rather than wet. Move the pot to a frost-free spot if a hard freeze is forecast.

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
0.711.42.12.90.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.711.42.12.90.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

White Rain Lily: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.160.780.310.30.78
Feb0.530.260.810.350.370.93
Mar0.870.431.150.520.581.52
Apr1.180.611.40.640.761.95
May1.460.831.610.780.952.45
Jun1.610.991.740.921.142.79
Jul1.611.071.9811.222.85
Aug1.490.951.860.931.122.6
Sep1.240.721.490.740.862.08
Oct0.870.471.150.530.581.49
Nov0.470.220.840.360.370.96
Dec0.310.140.650.270.260.68
Year126.8415.57.378.5121.08

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 low water in the Central Valley, like white rain lily. Plants that drink alike can share one valve and one schedule.

Star of BethlehemOrnithogalum arabicumlow water, Central Valley1.07 gal/sq ft in JulyIvy Leaf CyclamenCyclamen hederifoliumlow water, Central Valley1.07 gal/sq ft in JulySummer SnowflakeLeucojum aestivumlow water, Central Valley1.07 gal/sq ft in JulyHyacinthHyacinthus spp.low water, Central Valley1.07 gal/sq ft in JulySea SquillDrimia maritimalow water, Central Valley1.07 gal/sq ft in JulyLavenderLavandula spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyCrape MyrtleLagerstroemia spp., hybrids & cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyGreek Strawberry TreeArbutus andrachnelow water, Central Valley1.07 gal/sq ft in JulyWinter-Blooming BergeniaBergenia crassifolialow water, Central Valley1.07 gal/sq ft in JulyMexican FleabaneErigeron karvinskianuslow water, Central Valley1.07 gal/sq ft in JulyWinter JasmineJasminum nudiflorumlow water, Central Valley1.07 gal/sq ft in JulyValley OakQuercus lobatalow water, Central Valley1.07 gal/sq ft in JulyCoral FountainRusselia equisetiformislow water, Central Valley1.07 gal/sq ft in JulyWhite SageSalvia apianalow 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 white rain lily, 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 much should I water white rain lily in summer?

In July, established white rain lily needs about 0.8 gallons in the Central Valley, 1.4 gallons on the south coast and 0.7 gallons in the South Inland zone each week, for a plant 2 feet across. Water deeply and let the top of the soil dry before the next watering. Skip a watering after a soaking rain.

How much water does white rain lily need per day?

In July in the Central Valley, established white rain lily needs about 0.1 gallons a day for a plant 2 feet across and about 0.4 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 white rain lily change across California?

Yes. WUCOLS rates white rain lily separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, low water in the Central Valley zone, moderate water in the South Coastal zone, low water in the South Inland zone, low 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 is it called a rain lily?

Its flowers tend to open soon after a rain, which gives the plant its common name. Blooms come mainly in late summer and fall. In a garden, letting the soil dry slightly between soakings helps it flower.

Can white rain lily grow in a pond?

Yes. It comes from marshes and bogs and can grow partly submerged at the edge of a water garden. Keep the leaves above the water line. In an ordinary bed it still wants well-drained soil.

Should I deadhead white rain lily?

Cut faded flower stems off at the base if you do not want seedlings, since it reseeds. To save seed instead, collect it from the center of the flower after the petals drop.

How do I divide rain lily bulbs?

Lift a crowded clump in spring and separate the offsets. Replant them at the same depth and water them in. The clump spreads by offsets, so it slowly fills in again.

Does white rain lily need full sun?

It grows in full sun or part shade and flowers best in full sun. In very hot inland gardens, afternoon shade helps prevent leaf dieback and a weak bloom. A shaded bed also dries out more slowly.

Is white rain lily evergreen?

It keeps its leaves where winter lows stay above the high teens. Colder freezes kill the foliage back, and new leaves come from the bulbs. It is reported to survive temperatures near 0 degrees F.

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Sources