How often to water Formosa sugar palm in California
In July on the south coast, established Formosa sugar palm in loam needs a deep watering about every 11 days: about 55 gallons each time under a 10 foot canopy, about 35 gallons a week. Formosa sugar palm is a clumping palm from Taiwan that builds several short trunks to about 10 feet. Its feather-like leaves carry leaflets that widen toward the tip, with silvery undersides and notched edges. It takes regular water and grows in full sun, but it is tender to frost.
How often to water Formosa sugar palm, 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: 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 under the branches, and skip a watering after a good soaking rain.
How to tell it needs water
- Soil dry 3 inches down at the edge of the clump means it is time for a deep soak
- Leaflets that droop or fold over dry soil on a hot afternoon can point to a thirsty clump
- Leaf damage after a winter night near freezing is more likely cold injury than thirst, since this palm tolerates only about 30 to 32 degrees F
- Yellowing lower fronds over soil that stays soggy for days can point to poor drainage rather than a need for more water
- The silvery color under each leaflet is normal for this palm and is not a sign of stress
How to water it
- Water around the whole clump with drip emitters or a slow hose, covering the base of every trunk
- Soak until water reaches about 18 inches down, then let the top few inches dry before the next soak
- Spread coarse mulch over the root area, pulled a few inches back from the trunks
- Plant in soil that drains well, and set the palm on a low mound where clay holds winter water
- Add emitters on the outer side as new trunks widen the clump
Through the seasons
Water a new Formosa sugar palm deeply through its first summer, so the root ball never dries while roots move into the surrounding soil. An established clump still wants regular water in the warm months. It is evergreen, so it keeps its leaves and needs some moisture all year. Winter rain covers most of the cool months on the south coast, with a soil check during long dry spells. Frost is the bigger winter risk, since it is rated hardy only to about 30 to 32 degrees F. WUCOLS rates Formosa sugar palm moderate water on the south coast. WUCOLS has not evaluated it for the north-central coast, the Central Valley, South Inland, the high desert or the low desert.
In pots
A young Formosa sugar palm can live in a large container for a time, but a mature clump spreads 6 to 8 feet wide. Check the mix 2 inches down every few days in summer, and more often when the pot sits on hot paving. Water until it runs from the drainage holes, then empty the saucer. A pot is also an easy answer to its frost tenderness. Move it under an eave or against a warm wall when nights near freezing are forecast, and let the mix dry a little more between winter waterings.
- A year
- no figure
- Reference
- Sacramento climate table
- Counts
- Plant need, before sprinkler losses
WUCOLS lists Formosa Sugar Palm as not evaluated for the Central Valley zone, so no monthly figure is computed here.
Monthly water need by climate zone
Formosa Sugar Palm: gallons per square foot per month, by WUCOLS climate zone
| Month | N. Coast | C. Valley | S. Coast | S. Inland | Hi Desert | Lo Desert |
|---|---|---|---|---|---|---|
| Jan | – | – | 0.78 | – | – | – |
| Feb | – | – | 0.81 | – | – | – |
| Mar | – | – | 1.15 | – | – | – |
| Apr | – | – | 1.4 | – | – | – |
| May | – | – | 1.61 | – | – | – |
| Jun | – | – | 1.74 | – | – | – |
| Jul | – | – | 1.98 | – | – | – |
| Aug | – | – | 1.86 | – | – | – |
| Sep | – | – | 1.49 | – | – | – |
| Oct | – | – | 1.15 | – | – | – |
| Nov | – | – | 0.84 | – | – | – |
| Dec | – | – | 0.65 | – | – | – |
| Year | – | – | 15.5 | – | – | – |
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 not evaluated in the Central Valley, like Formosa sugar palm. Plants that drink alike can share one valve and one schedule.
Hawthorn MapleAcer crataegifoliumnot rated, Central Valleyno Central Valley rating
Mountain MapleAcer glabrumnot rated, Central Valleyno Central Valley rating
Miyabe MapleAcer miyabeinot rated, Central Valleyno Central Valley rating
Everglades PalmAcoelorraphe wrightiinot rated, Central Valleyno Central Valley rating
Pink CedarAcrocarpus fraxinifoliusnot rated, Central Valleyno Central Valley rating
YellowwoodAfrocarpus falcatus (Podocarpus falcatus)not rated, Central Valleyno Central Valley rating
New Caledonian PineAraucaria columnaris (A. cookii)not rated, Central Valleyno Central Valley rating
NeemAzadirachta indicanot rated, Central Valleyno Central Valley rating
Bismarck PalmBismarckia nobilisnot rated, Central Valleyno Central Valley rating
American HornbeamCarpinus caroliniananot rated, Central Valleyno Central Valley rating
Japanese HornbeamCarpinus japonicanot rated, Central Valleyno Central Valley rating
Chilean Feather BambooChusquea culeou (C. breviglumis)not rated, Central Valleyno Central Valley rating
American YellowwoodCladrastis kentukeanot rated, Central Valleyno Central Valley rating
BlackbrushColeogyne ramosissimanot rated, Central Valleyno Central Valley rating
Pagoda DogwoodCornus alternifolianot rated, Central Valleyno Central Valley rating
Giant DogwoodCornus controversanot rated, Central Valleyno Central Valley ratingTurn this into minutes on your water days
Every city page has a calculator that takes Formosa sugar palm, 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 water does Formosa sugar palm need per day?
In July on the south coast, established Formosa sugar palm needs about 5.0 gallons a day under a 10 foot canopy and about 20 gallons a day under a 20 foot canopy. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.
Does watering for Formosa sugar palm change across California?
Yes. WUCOLS rates Formosa sugar palm separately for each of the six California climate zones: not evaluated in the North-Central Coastal zone, not evaluated in the Central Valley zone, moderate water in the South Coastal zone, not evaluated 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.
How big does Formosa sugar palm get?
It grows about 8 to 10 feet tall and 6 to 8 feet wide. Several short trunks rise from one clump instead of a single tall stem. Leave room for that width when you place emitters.
Is Formosa sugar palm frost hardy?
Only lightly. It is rated hardy to about 30 to 32 degrees F, so a hard frost can damage it. Plant it in a warm, sheltered spot or keep it in a pot you can move.
Does Formosa sugar palm need full sun?
It is listed for full sun with regular watering. A clump in full sun dries out faster than one in a shaded courtyard. Check the soil before each soak rather than watering on habit.
Does Formosa sugar palm flower?
Its flowers are insignificant and are not why people grow it. The palm is grown for its clumping form and silvery-backed leaves. Care centers on steady water and frost protection instead.
Why are the leaflets on my Formosa sugar palm notched?
Notched leaflet edges are normal for this species. Each leaflet is narrow at the base and widens toward the tip, with a silvery underside. None of this signals a watering problem.
Where does Formosa sugar palm come from?
It comes from Taiwan, once known as Formosa. It is a palm for nearly frost-free gardens. In California, WUCOLS has rated it only for the south coast.
More plant watering guides
Sources
- WUCOLS IV plant water use classification for Arenga engleri, 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