WateringTimesWatering plan, $19
Yucca faxoniana, WUCOLS IV

How often to water giant white yucca in California

In July in the South Inland zone, established giant white yucca in loam needs a deep soak only about once a month or less: about 8.8 gallons each time for a plant 4 feet across. Giant white yucca is a tree-like yucca native to Texas, New Mexico and northeast Mexico. It builds one or two upright trunks topped by rosettes of stiff, sharp-tipped leaves up to about 3 feet long. Clusters of creamy white bell flowers rise well above the leaves. It needs very little water once established, and soggy soil harms it more than drought.

ShrubSucculentRated for 3 of 6 zones

How often to water giant white yucca, month by month

Your city
Plant width
4 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 giant white yucca 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 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

  • A young plant in its first summer needs a soak when the soil is dry 3 to 4 inches down
  • A soft, darkening trunk base or a rosette that yellows and leans over damp soil points to root rot from too much water
  • Dark spots on the leaves can be yucca leaf spot, a disease that more water will not cure, so keep sprinkler spray off the foliage
  • Clusters of small insects on the flower spike are aphids, a pest problem rather than a watering one

How to water it

  • Water a young giant white yucca with a slow soak at the edge of its root ball, then let the soil dry deeply before the next one
  • Set one or two drip emitters a short way from the trunk, never right against it
  • Use a gravel or rock mulch around the trunk rather than a thick organic layer that stays damp
  • Plant in rocky, sandy or limestone soil that drains fast, on a mound or slope if your ground is heavy clay
  • Taper off watering once the plant is established, and give only an occasional deep soak in a long, hot dry spell

Through the seasons

Give a new giant white yucca a deep soak whenever the soil dries well down during its first summer, then taper off. Once established it needs very little water, and wet soil is a greater risk than drought. It is evergreen, and its needs change little through the year. Summer heat is when a young plant may need a soak. Desert winters are often dry, so check the soil around a young plant during long dry spells. WUCOLS rates it very low water in South Inland and in the high desert. It rates low water in the low desert. WUCOLS has not evaluated it for the north-central coast, the Central Valley or the south coast.

In pots

Giant white yucca grows into a tree-sized plant, so a container suits only a young one. Use a heavy pot and a gritty, fast-draining mix, since the stiff leaves make it top-heavy. Check the mix 2 to 3 inches down every few days in summer heat, and water only when it is dry there. Water until it drains from the holes, then empty the saucer at once. In winter, water sparingly and keep the pot out of standing rain. Place it where the sharp leaf tips cannot catch people walking past.

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

WUCOLS lists Giant White Yucca as not evaluated for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Giant White Yucca: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan–––0.080.070.31
Feb–––0.090.090.37
Mar–––0.130.150.61
Apr–––0.160.190.78
May–––0.20.240.98
Jun–––0.230.291.12
Jul–––0.250.31.14
Aug–––0.230.281.04
Sep–––0.190.210.83
Oct–––0.130.150.6
Nov–––0.090.090.38
Dec–––0.070.070.27
Year–––1.842.138.43

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 giant white yucca. Plants that drink alike can share one valve and one schedule.

Formosa Sugar PalmArenga englerinot rated, Central Valleyno Central Valley ratingChilean Feather BambooChusquea culeou (C. breviglumis)not rated, Central Valleyno Central Valley ratingBlackbrushColeogyne ramosissimanot rated, Central Valleyno Central Valley ratingGlaucous Scorpion VetchCoronilla valentina glaucanot rated, Central Valleyno Central Valley ratingWillowleaf CotoneasterCotoneaster salicifoliusnot rated, Central Valleyno Central Valley ratingMadagascar SagoCycas thouarsii (SHADE)not rated, Central Valleyno Central Valley ratingIrish HeathDaboecia cantabricanot rated, Central Valleyno Central Valley ratingButterfly PalmDypsis lutescens (Areca)not rated, Central Valleyno Central Valley ratingPurple SpurgeEuphorbia dulcisnot rated, Central Valleyno Central Valley ratingUmbrella BambooFargesia murielaenot rated, Central Valleyno Central Valley ratingBlue Fountain BambooFargesia nitida (Sinarundinaria nitida) (BAMBOO)not rated, Central Valleyno Central Valley ratingPrickly HeathGaultheria mucronata (Pernettya mucronata)not rated, Central Valleyno Central Valley ratingOtterbossieGossypium harknessiinot rated, Central Valleyno Central Valley ratingBox-leaved HollyIlex crenatanot rated, Central Valleyno Central Valley ratingBellyache BushJatropha gossypiifolianot rated, Central Valleyno Central Valley ratingMountain LaurelKalmia latifolianot 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 giant white yucca, 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 giant white yucca need per day?

In July in the South Inland zone, established giant white yucca needs about 0.1 gallons a day for a plant 4 feet across and about 0.4 gallons a day for a plant 8 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 giant white yucca change across California?

Yes. WUCOLS rates giant white yucca separately for each of the six California climate zones: not evaluated in the North-Central Coastal zone, not evaluated in the Central Valley zone, not evaluated in the South Coastal zone, very low water in the South Inland zone, very low water in the High and Intermediate Desert zone, low water in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Is giant white yucca poisonous to pets?

Yes. It is listed as harmful to dogs and cats if eaten, and it can irritate skin. The plant contains saponins, which can cause vomiting and diarrhea. Wear gloves when you handle it.

How big does giant white yucca get?

It can reach about 13 to 26 feet tall and 8 to 13 feet wide. It takes 10 to 20 years to reach full size. Extra water will not hurry it and raises the risk of root rot.

Should I cut off the dead flower stalk?

Yes, once flowering ends. It needs no other pruning. Cut the spent stalk at its base with long-handled loppers, keeping clear of the sharp leaf tips.

How do I start a new giant white yucca?

Grow it from seed, or remove a rooted sucker from the base of an older plant. Seed may need hand pollination to set. Keep a young plant in fast-draining soil and water it lightly until it roots.

Does giant white yucca attract wildlife?

Its flowers provide nectar, and it is a larval host plant for the yucca giant skipper. Birds and butterflies also visit it.

More plant watering guides

Spicy JatrophaPachypodiumShore PineBlue Dwarf Japanese Stone PineHuckleberry OakSlender Lady PalmThanksgiving CactusSand Ryegrass

Sources