WateringTimesWatering plan, $19
Yucca schottii, WUCOLS IV

How often to water mountain yucca in California

In July on the south coast, established mountain 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. Mountain yucca is a rosette-forming succulent from mountain ranges where Arizona, New Mexico and Mexico meet. Stiff, narrow, bluish gray-green leaves with sharp tips form a rosette 3 to 6 feet tall and wide, and it slowly builds a trunk that can reach 15 feet. Small, waxy, creamy white flowers top a short stalk each summer.

ShrubSucculentRated for 3 of 6 zones

How often to water mountain 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 mountain 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

  • Stiff, upright leaves on a mountain yucca mean it has all the water it needs
  • Leaves curling lengthwise after a very long, hot dry spell can mean it is time for one deep soak
  • A soft, dark base or collapsing center points to rot from wet soil
  • Old lower leaves drying as the trunk lengthens is normal aging

How to water it

  • Give a deep, slow soak only after the ground has dried completely
  • Plant in sun to light shade where water never pools
  • Keep sprinklers and lawn water well away
  • Site it back from walkways, since every leaf ends in a sharp point
  • Help a new plant settle with a few deep soaks in its first summer

Through the seasons

Help a new plant along with a few deep soaks in its first summer, then cut back. Established plants live on very little water, with rare deep soaks in long hot spells. A summer flower stalk appears, and the trunk builds slowly over many years. The south coast and the high desert get a very low water rating from WUCOLS for mountain yucca. The low desert gets a low water rating. The north-central coast, the Central Valley and South Inland have no WUCOLS evaluation for it.

In pots

A young mountain yucca can grow for years in a large, heavy pot of fast-draining cactus mix, which keeps its roots from sitting wet. Water only after the mix has dried all the way down, then let it drain fully. In summer, a pot may need a soak every couple of weeks in heat. Never leave water in the saucer. Keep the pot away from walkways. In winter, rain is usually plenty.

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

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

Monthly water need by climate zone

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan––0.08–0.070.31
Feb––0.08–0.090.37
Mar––0.11–0.150.61
Apr––0.14–0.190.78
May––0.16–0.240.98
Jun––0.17–0.291.12
Jul––0.2–0.31.14
Aug––0.19–0.281.04
Sep––0.15–0.210.83
Oct––0.11–0.150.6
Nov––0.08–0.090.38
Dec––0.07–0.070.27
Year––1.55–2.138.43

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 mountain 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 mountain 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 mountain yucca need per day?

In July on the south coast, established mountain yucca needs about 0.1 gallons a day for a plant 4 feet across and about 0.3 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 mountain yucca change across California?

Yes. WUCOLS rates mountain 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, very low water in the South Coastal zone, not evaluated 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.

How tall does mountain yucca get?

The rosette is 3 to 6 feet tall and wide. Over many years it forms a trunk up to 15 feet tall. Branched plants can be 10 feet wide.

When does mountain yucca bloom?

Small, waxy, creamy white flowers appear on a 2 to 3 foot stalk in summer. Extra water does not force bloom. Full sun helps.

Can mountain yucca grow in shade?

It grows in sun to light shade. Deep shade weakens it. Shade also keeps soil wetter, so water less.

Is mountain yucca a hybrid?

It may be a natural hybrid between banana yucca and another mountain yucca. It is sometimes sold under other names. Check the label.

Where is mountain yucca native?

It is native to the mountains of southeastern Arizona, southwestern New Mexico and northeastern Mexico. It is not native to California. It suits dry, sunny gardens.

More plant watering guides

Gibraltar CandytuftBox-leaved HollyPrivet-Leaved JasmineBellyache BushMountain LaurelBlue Hair GrassChilean BellflowerJapanese Larch

Sources