WateringTimesWatering plan, $19
Bismarckia nobilis, WUCOLS IV

How often to water Bismarck palm in California

In July on the south coast, established Bismarck 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. Bismarck palm is a massive fan palm from the open grasslands of Madagascar, the only species in its genus. Its stiff, rounded, silver-blue leaves can reach 9 feet across on a single gray to tan trunk, and garden trees rarely pass 40 feet. It needs full sun, good drainage and lots of room for its huge crown.

TreePalm or cycadRated for 2 of 6 zones

How often to water Bismarck palm, month by month

Your city
Canopy width
10 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 Bismarck palm 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 under the branches, 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 canopy width

A tree with its canopy width marked across the widest branches and the circle under it shaded blue

Measure across the branches, from the tips of the outer leaves on one side to the tips on the other. A tape works, or pace it out.

Water the whole circle under the branches, shown in blue. The gallons here cover that circle.

A wider canopy means more gallons each watering, not more waterings. While the tree is young, measure again each spring.

How to tell it needs water

  • Soil dry several inches down around the trunk in summer means Bismarck palm can take a deep watering
  • Older leaves browning early in a long dry spell suggest the root zone dried
  • Leaves browning after a frost point to cold damage, which usually recovers
  • A declining crown with moist soil calls for a pest check, not more water

How to water it

  • Water deeply over the whole root zone, then let the top few inches dry
  • Plant in full sun in well-drained soil, clay included
  • Leave ample room for the huge crown
  • Remove only dead leaves
  • Rake up the large brown fruit to keep paths clear

Through the seasons

Water a new palm regularly through its first summers. Established palms want moderate, deep watering in the dry season, more in the low desert. The silver form takes cold down to about 27 degrees F, and frost-damaged palms usually recover. It is a confirmed California host of the South American palm weevil, so watch the crown. WUCOLS rates Bismarck palm moderate water on the south coast and in the low desert. WUCOLS marks it as not suited to the north-central coast or the high desert, and has not evaluated it for the Central Valley or South Inland.

In pots

Bismarck palm grows far too large for a container long term, but a young one can live in a big, heavy pot for a few years. Use a well-drained mix. Water when the top couple of inches are dry, until water drains from the base. In summer, check every few days, since its big leaves lose water fast. Do not let it stand in water. Protect potted plants from frost.

1 Your climate zone six WUCOLS zones, each from its own reference city
Not ratedWUCOLS does not rate Bismarck Palm for the Central Valley zone
A year
no figure
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses

WUCOLS lists Bismarck Palm as not evaluated for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Bismarck Palm: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan––0.78––0.78
Feb––0.81––0.93
Mar––1.15––1.52
Apr––1.4––1.95
May––1.61––2.45
Jun––1.74––2.79
Jul––1.98––2.85
Aug––1.86––2.6
Sep––1.49––2.08
Oct––1.15––1.49
Nov––0.84––0.96
Dec––0.65––0.68
Year––15.5––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 not evaluated in the Central Valley, like Bismarck palm. Plants that drink alike can share one valve and one schedule.

Hawthorn MapleAcer crataegifoliumnot rated, Central Valleyno Central Valley ratingMountain MapleAcer glabrumnot rated, Central Valleyno Central Valley ratingMiyabe MapleAcer miyabeinot rated, Central Valleyno Central Valley ratingEverglades PalmAcoelorraphe wrightiinot rated, Central Valleyno Central Valley ratingPink CedarAcrocarpus fraxinifoliusnot rated, Central Valleyno Central Valley ratingYellowwoodAfrocarpus falcatus (Podocarpus falcatus)not rated, Central Valleyno Central Valley ratingNew Caledonian PineAraucaria columnaris (A. cookii)not rated, Central Valleyno Central Valley ratingFormosa Sugar PalmArenga englerinot rated, Central Valleyno Central Valley ratingNeemAzadirachta indicanot rated, Central Valleyno Central Valley ratingAmerican HornbeamCarpinus caroliniananot rated, Central Valleyno Central Valley ratingJapanese HornbeamCarpinus japonicanot rated, Central Valleyno Central Valley ratingAmerican YellowwoodCladrastis kentukeanot rated, Central Valleyno Central Valley ratingPagoda DogwoodCornus alternifolianot rated, Central Valleyno Central Valley ratingGiant DogwoodCornus controversanot rated, Central Valleyno Central Valley ratingMadagascar SagoCycas thouarsii (SHADE)not rated, Central Valleyno Central Valley ratingButterfly PalmDypsis lutescens (Areca)not rated, Central Valleyno Central Valley rating
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes Bismarck 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 Bismarck palm need per day?

In July on the south coast, established Bismarck 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 Bismarck palm change across California?

Yes. WUCOLS rates Bismarck palm separately for each of the six California climate zones: not suited to this region 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 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.

How big does Bismarck palm get?

In gardens it usually stays under 40 feet, though it can grow much taller in the wild. Leaves reach 9 feet across. Give it a lot of room.

How cold hardy is Bismarck palm?

The green form is damaged at 32 degrees F, while the silver form tolerates about 27 degrees F. Cold-damaged palms usually recover quickly. Plant it in a warm spot.

Does Bismarck palm grow in clay?

Yes, it seems to perform in clay soils, though well-drained soil is best. It adapts to acidic or alkaline soil. Avoid soggy spots.

Is Bismarck palm at risk from palm weevils?

It is listed as a confirmed host of the South American palm weevil in California. Watch for a declining crown. Keep the palm healthy with good watering.

Is Bismarck palm fruit messy?

Yes, the large brown fruit can be messy. Keep it away from patios and pools. Rake up fallen fruit.

More plant watering guides

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Sources