WateringTimesWatering plan, $19
Agave spp. & cvs., WUCOLS IV

How often to water century plant in California

In July in the Central Valley, established century plant needs about 0.2 gallons a week for a plant 2 feet across. Century plant is the common name for agaves, rosette-forming succulents of the Americas, most of them from Mexico, with thick, often spine-tipped leaves. Most bloom only once, sending up a towering stalk before the main rosette dies, while offsets carry on. They want full sun, well-drained soil and very little water.

SucculentRated for 5 of 6 zones

How often to water century plant, month by month

Your city
Plant width
2 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 century plant and the rest of your yard, on the days your water supplier allows.Get the plan for $19

How this is worked out: the plant’s WUCOLS rating times your city’s climate for the month, over the area the plant covers. 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

  • Leaves looking thin and wrinkled after a long, hot dry spell mean the plant could use a deep soak
  • A soft, collapsing rosette with rotted tissue at the base points to root and crown rot from wet soil
  • Decline that soil moisture cannot explain can point to agave weevils, a known pest of these plants
  • Bleached or scorched patches on the leaves point to leaf scorch rather than a water shortage
  • A tall flower stalk rising from the center means the main rosette will die after blooming, whatever the watering

How to water it

  • Water the soil around the rosette slowly so it soaks in rather than running off
  • Let the soil dry deeply between waterings, since the thick leaves store water
  • Plant in full sun in fast-draining sandy or gravelly soil, or on a slope
  • Group it with cacti and other succulents on the same sparing irrigation line
  • Site large kinds well away from paths, and move emitters outward as offsets fill in

Through the seasons

Water a new planting only lightly until roots take hold, letting the soil dry between soaks. Once established, it needs very little water, and too much summer water invites root rot. It stays evergreen, and after many years a mature rosette may send up its single flower stalk and then die, leaving offsets behind. WUCOLS rates century plant very low water on the north-central coast, in the Central Valley and in South Inland. The high desert and the low desert also rate very low water. WUCOLS has not evaluated it for the south coast.

In pots

Smaller agaves make striking container plants, and they can even grow indoors by a hot, sunny window. Use a gritty cactus mix and a pot with a large drainage hole. In summer heat, water only when the mix is dry most of the way down, then let it drain completely. Never leave the pot in a saucer of water. In winter, water rarely, and not at all while rain keeps an outdoor pot damp.

1 Your climate zone six WUCOLS zones, each from its own reference city
0.27gal per sq ft in JulyVery low water use in the Central Valley zone
A year
1.71 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.070.150.220.300.04JAN0.07FEB0.11MAR0.15APR0.21MAY0.25JUN0.27JUL0.24AUG0.18SEP0.12OCT0.06NOV0.03DEC0.070.150.220.300.04JFM0.15AMJ0.27JAS0.12OND
Gallons per square foot per month, Central Valley. Peak 0.27 in Jul, 1.71 a year.

Monthly water need by climate zone

Century Plant: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.040.04–0.080.070.08
Feb0.050.07–0.090.090.09
Mar0.090.11–0.130.150.15
Apr0.120.15–0.160.190.2
May0.150.21–0.20.240.24
Jun0.160.25–0.230.290.28
Jul0.160.27–0.250.30.29
Aug0.150.24–0.230.280.26
Sep0.120.18–0.190.210.21
Oct0.090.12–0.130.150.15
Nov0.050.06–0.090.090.1
Dec0.030.03–0.070.070.07
Year1.21.71–1.842.132.11

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 13

Rated very low water in the Central Valley, like century plant. Plants that drink alike can share one valve and one schedule.

CactusOpuntia spp. & cvs. (CA natives and non-natives)very low water, Central Valley0.27 gal/sq ft in JulyCypress SpurgeEuphorbia cyparissiasvery low water, Central Valley0.27 gal/sq ft in JulyVariegated Century PlantAgave americana var. marginatavery low water, Central Valley0.27 gal/sq ft in JulyDesert AgaveAgave desertivery low water, Central Valley0.27 gal/sq ft in JulyThread Leaf AgaveAgave filiferavery low water, Central Valley0.27 gal/sq ft in JulyPalmer AgaveAgave palmerivery low water, Central Valley0.27 gal/sq ft in JulyButterfly AgaveAgave potatorumvery low water, Central Valley0.27 gal/sq ft in JulySisalAgave sisalanavery low water, Central Valley0.27 gal/sq ft in JulyBlue AgaveAgave tequilana & ssp. & cvs.very low water, Central Valley0.27 gal/sq ft in JulyUtah AgaveAgave utahensisvery low water, Central Valley0.27 gal/sq ft in JulyQueen Victoria AgaveAgave victoriae-reginaevery low water, Central Valley0.27 gal/sq ft in JulyBeaked YuccaYucca rostrata ssp. & cvs.very low water, Central Valley0.27 gal/sq ft in JulyParry's AgaveAgave parryivery low water, Central Valley0.27 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 century plant, 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 should I water century plant in summer?

In July, established century plant needs about 0.2 gallons in the Central Valley and 0.2 gallons in the South Inland zone each week, for a plant 2 feet across. Water deeply and let the top of the soil dry before the next watering. Skip a watering after a soaking rain.

How much water does century plant need per day?

In July in the Central Valley, established century plant needs about 0.0 gallons a day for a plant 2 feet across and about 0.1 gallons a day for a plant 4 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 century plant change across California?

Yes. WUCOLS rates century plant separately for each of the six California climate zones: very low water in the North-Central Coastal zone, very low water 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, very 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.

Does a century plant really take 100 years to bloom?

No. The name comes from an old belief, but American century plant usually blooms after 10 to 25 years. Its flower stalk can reach 15 to 30 feet or more.

Does a century plant die after it blooms?

Yes, the main rosette dies after flowering, since most agaves bloom only once. Offsets around its base carry on, so the clump usually continues.

Is century plant sap dangerous?

The sap can irritate skin, because it contains calcium oxalate crystals. Wear gloves and long sleeves when cutting leaves or removing offsets.

How do I propagate a century plant?

Dig and replant the offsets that form at the base, especially as the parent flowers. Agaves can also be grown from seed.

Can century plants grow near the coast?

Yes. Many agaves do particularly well in coastal California's mediterranean climate, and American century plant is highly salt tolerant.

What pests attack century plants?

Agave weevils are the main threat, and mealybugs and scale also show up. Slugs and snails may chew the leaves.

More plant watering guides

SisalBlue AgaveUtah AgaveQueen Victoria AgaveCreosote BushPurple SageBlack SageBeaked Yucca

Sources