How often to water star of Bethlehem in California
In July in the Central Valley, established star of Bethlehem needs about 0.8 gallons a week for a plant 2 feet across. This star of Bethlehem is Ornithogalum arabicum, also called Arabian star flower, a bulb with blue-green, strap-shaped leaves. Its spikes of white, star-shaped flowers open slowly from bottom to top and last a long time in a vase. Leaves die back gradually after flowering. Bulbs want rich, well-drained soil in full sun.
How often to water star of Bethlehem, month by month
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.
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.
How to tell it needs water
- Soil dry 3 inches down beside the leaves in winter or spring means star of Bethlehem can take water
- Leaves wilting before the flower spikes rise point to a dry spring
- Leaves yellowing after bloom is the normal start of its rest
- Soft, rotting bulbs point to soggy soil, not thirst
How to water it
- Water while leaves are growing if rain falls short
- Let the soil dry between waterings
- Plant bulbs in fall about 4 inches deep and 2 to 5 inches apart
- Choose full sun and rich, well-drained soil
- Stop watering as the leaves fade after bloom
Through the seasons
Plant bulbs in fall and water them in well. Through winter and spring, water only when rain falls short and the soil has dried. Flower spikes rise above the blue-green leaves and open slowly from the bottom up. Afterward the leaves die back gradually as the bulbs rest, and they need no water then. WUCOLS rates star of Bethlehem low water on the north-central coast, in the Central Valley, on the south coast and in South Inland. WUCOLS has not evaluated it for the high desert or the low desert.
In pots
Star of Bethlehem grows well in pots, which keep its bulbs from sitting wet. Plant bulbs in fall in a rich, well-drained mix. Water when the top couple of inches dry, until it drains through. In winter and spring, rain may cover outdoor pots. Do not leave water standing in the saucer. After bloom, let the leaves die back and keep the pot dry until the next growing season.
- A year
- 6.84 gal per sq ft
- Reference
- Sacramento climate table
- Counts
- Plant need, before sprinkler losses
Monthly water need by climate zone
Star of Bethlehem: gallons per square foot per month, by WUCOLS climate zone
| Month | N. Coast | C. Valley | S. Coast | S. Inland | Hi Desert | Lo Desert |
|---|---|---|---|---|---|---|
| Jan | 0.15 | 0.16 | 0.31 | 0.31 | – | – |
| Feb | 0.21 | 0.26 | 0.32 | 0.35 | – | – |
| Mar | 0.35 | 0.43 | 0.46 | 0.52 | – | – |
| Apr | 0.47 | 0.61 | 0.56 | 0.64 | – | – |
| May | 0.58 | 0.83 | 0.64 | 0.78 | – | – |
| Jun | 0.64 | 0.99 | 0.69 | 0.92 | – | – |
| Jul | 0.64 | 1.07 | 0.79 | 1 | – | – |
| Aug | 0.6 | 0.95 | 0.74 | 0.93 | – | – |
| Sep | 0.5 | 0.72 | 0.6 | 0.74 | – | – |
| Oct | 0.35 | 0.47 | 0.46 | 0.53 | – | – |
| Nov | 0.19 | 0.22 | 0.33 | 0.36 | – | – |
| Dec | 0.12 | 0.14 | 0.26 | 0.27 | – | – |
| Year | 4.8 | 6.84 | 6.2 | 7.37 | – | – |
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 5
Rated low water in the Central Valley, like star of Bethlehem. Plants that drink alike can share one valve and one schedule.
Ivy Leaf CyclamenCyclamen hederifoliumlow water, Central Valley1.07 gal/sq ft in July
Summer SnowflakeLeucojum aestivumlow water, Central Valley1.07 gal/sq ft in July
White Rain LilyZephyranthes candidalow water, Central Valley1.07 gal/sq ft in July
HyacinthHyacinthus spp.low water, Central Valley1.07 gal/sq ft in July
Sea SquillDrimia maritimalow water, Central Valley1.07 gal/sq ft in JulyTurn this into minutes on your water days
Every city page has a calculator that takes star of Bethlehem, 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 star of Bethlehem in summer?
In July, established star of Bethlehem needs about 0.8 gallons in the Central Valley, 0.6 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 star of Bethlehem need per day?
In July in the Central Valley, established star of Bethlehem 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 star of Bethlehem change across California?
Yes. WUCOLS rates star of Bethlehem separately for each of the six California climate zones: low water in the North-Central Coastal zone, low water in the Central Valley zone, low water in the South Coastal zone, low water in the South Inland zone, not evaluated in the High and Intermediate Desert zone, not evaluated in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.
Is star of Bethlehem good for cutting?
Yes, its flowers are long lasting and make excellent cut flowers. They open from the bottom of the spike upward. Arrangements stay fresh for a long time.
Should I water star of Bethlehem in summer?
No, the leaves die back after flowering and the bulbs rest. Summer water can rot them. Resume watering when growth starts.
How deep should I plant star of Bethlehem?
Plant bulbs about 4 inches deep and 2 to 5 inches apart in fall. Use rich, well-drained soil. Choose full sun.
Can star of Bethlehem grow in pots?
Yes, it grows well in containers. Use a well-drained mix. Keep the pot dry during summer rest.
What problems affect star of Bethlehem?
It has no significant pest or disease issues. Bulb rot is the main risk in wet soil. Good drainage prevents it.
More plant watering guides
Sources
- WUCOLS IV plant water use classification for Ornithogalum arabicum, the University of California survey California agencies use for landscape plan reviewRead August 23, 2026 on wucols.ucdavis.edu
- Model Water Efficient Landscape Ordinance, adopted text and appendices, effective 2025-01-02 · monthly reference evapotranspiration per city, Appendix CRead August 23, 2026 on water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Water-Use-And-Efficiency/MWELO-Rulemaking/Final-MWELO-Text-and-Appendices_20250103.pdf
- UC Statewide IPM Program, irrigation scheduling using evapotranspirationRead September 30, 2026 on ipm.ucanr.edu/PMG/GARDEN/ENVIRON/evap.html
- Shaw and Pittenger, Landscape Irrigation System Evaluation and Management, UC Cooperative Extension, 2009Read September 30, 2026 on ucanr.edu/sites/default/files/2013-02/160836.pdf
- Pittenger, Water Management in Gardens and Landscapes, UC Riverside, 2017Read September 30, 2026 on ucanr.edu/sites/default/files/2017-03/258022.pdf