WateringTimesWatering plan, $19
Yucca gloriosa ssp. & cvs., WUCOLS IV

How often to water Spanish dagger in California

In July in the Central Valley, established Spanish dagger in loam needs a deep watering about every 20 days: about 8.8 gallons each time for a plant 4 feet across, about 3.0 gallons a week. Spanish dagger, also called mound lily yucca, is a southeastern coastal yucca with rosettes of stiff, bluish green, spine-tipped leaves. Tall spikes of pendulous white bells, tinged red or purple, can appear from spring into fall. It slowly builds a woody trunk and offsets into a small colony, and it shrugs off salt spray, heat and drought.

ShrubSucculentRated for 6 of 6 zones

How often to water Spanish dagger, 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 Spanish dagger 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

  • Soil dry 6 inches down beside the rosette tells you Spanish dagger can use a deep soak in a long hot spell
  • Leaf tips scorching in an inland site with all-day sun suggest the plant wants afternoon shade
  • Leaves yellowing from the base of the rosette in soggy soil point to too much water
  • A soft, sunken trunk base after wet weather warns of rot from poor drainage

How to water it

  • Water Spanish dagger at the soil around the rosette, never into the leaf crown
  • Wet the soil about a foot down, then wait until it has dried well before watering again
  • Plant in well-drained sandy soil in sun or part shade, with afternoon shade in hot inland areas
  • Use gravel or bare ground around the base so the trunk stays dry
  • Water a little wider as offsets spread into a colony

Through the seasons

Give a new Spanish dagger occasional deep water through its first summer while roots spread. Established plants tolerate drought and need little irrigation anywhere WUCOLS rates it. The leaves stay evergreen, and flowers can open anytime from spring into fall. In hot inland gardens, it appreciates afternoon shade. On the north-central coast and the south coast, WUCOLS rates Spanish dagger very low water. It rates low water in the Central Valley, South Inland, the high desert and the low desert.

In pots

Spanish dagger suits a large, heavy pot of gritty, sandy mix, especially its variegated forms. In summer heat, probe the mix every few days and water deeply only once the top few inches are dry. Let every drop drain away and keep the saucer empty. Set the pot where the spine-tipped leaves will not jab anyone passing. In winter, water sparingly, since cold, wet mix invites rot.

1 Your climate zone six WUCOLS zones, each from its own reference city
1.07gal per sq ft in JulyLow water use in the Central Valley zone
A year
6.84 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.300.610.921.20.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.300.610.921.20.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

Spanish Dagger: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.040.160.080.310.30.31
Feb0.050.260.080.350.370.37
Mar0.090.430.110.520.580.61
Apr0.120.610.140.640.760.78
May0.150.830.160.780.950.98
Jun0.160.990.170.921.141.12
Jul0.161.070.211.221.14
Aug0.150.950.190.931.121.04
Sep0.120.720.150.740.860.83
Oct0.090.470.110.530.580.6
Nov0.050.220.080.360.370.38
Dec0.030.140.070.270.260.27
Year1.26.841.557.378.518.43

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 low water in the Central Valley, like Spanish dagger. Plants that drink alike can share one valve and one schedule.

LavenderLavandula spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRosemaryRosmarinus officinalislow water, Central Valley1.07 gal/sq ft in JulyBougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyOlive TreesOlea europaea ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyCrape MyrtleLagerstroemia spp., hybrids & cvs.low water, Central Valley1.07 gal/sq ft in JulyLantanaLantana camara ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyJunipersJuniperus spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySagebrushArtemisia spp. (shrubby)low water, Central Valley1.07 gal/sq ft in JulyWild PrivetLigustrum vulgarelow water, Central Valley1.07 gal/sq ft in JulyCoralberrySymphoricarpos orbiculatus (SHADE)low water, Central Valley1.07 gal/sq ft in JulySydney Golden WattleAcacia longifolialow water, Central Valley1.07 gal/sq ft in JulyBlue Leaf WattleAcacia salignalow water, Central Valley1.07 gal/sq ft in July
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes Spanish dagger, 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 often should I water Spanish dagger in summer?

In July, established Spanish dagger in loam needs a deep watering about every 20 days in the Central Valley, about once a month or less on the south coast and about every 22 days in the South Inland zone. Sandy soil holds less water, so waterings come closer together. Clay stretches them. Check the soil before each watering and skip one after a soaking rain.

How much water does Spanish dagger need per day?

In July in the Central Valley, established Spanish dagger needs about 0.4 gallons a day for a plant 4 feet across and about 1.7 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 Spanish dagger change across California?

Yes. WUCOLS rates Spanish dagger separately for each of the six California climate zones: very low water in the North-Central Coastal zone, low water in the Central Valley zone, very low water in the South Coastal zone, low water in the South Inland zone, 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 is Spanish dagger different from Spanish bayonet?

Both are spine-tipped yuccas from the Southeast, but Spanish dagger has bluish green leaves and flowers often tinged red or purple. Each needs sharp drainage and little water once established.

Does Spanish dagger need full sun?

It grows in sun or part shade, and in hot inland gardens afternoon shade helps. Shade slows drying, so wait for the soil to dry before watering.

Can Spanish dagger grow by the ocean?

Yes. It is native to the southeastern coast and resists salt spray. It is a good seaside plant in well-drained, sandy soil.

Is there a variegated Spanish dagger?

Yes. Forms such as 'Variegata' have leaves striped with cream or yellow. They need the same lean watering and sharp drainage as the species.

Can you overwater Spanish dagger?

Yes. Constantly wet soil rots the roots and trunk base. Water deeply only after the soil has dried well down.

More plant watering guides

Smoke TreeSaharan CypressLoquatBlue FescueJacarandaEnglish WalnutBaltic RushRocky Mountain Juniper

Sources