WateringTimesWatering plan, $19
Agave filifera, WUCOLS IV

How often to water thread leaf agave in California

In July in the Central Valley, established thread leaf agave needs about 0.2 gallons a week for a plant 2 feet across. Thread leaf agave is a compact Mexican agave that forms clustering rosettes about a foot tall and up to 2 feet wide. Its green leaves carry white threads along the margins, white markings on the surface and a sharp gray tip. It comes from rocky soils high in the mountains of Querétaro. In full sun with little water, the leaves often blush red.

SucculentRated for 6 of 6 zones

How often to water thread leaf agave, 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 thread leaf agave 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

  • Firm, upright leaves mean thread leaf agave does not need water
  • Leaves thinning and curling inward after a very long dry spell can signal thirst
  • Red tones on the leaves in full sun are a normal stress color, not a problem
  • A soft, dark base on a rosette points to rot from wet soil

How to water it

  • Water occasionally to rarely, only after the soil dries completely
  • Plant in full sun to part shade in fast-draining, rocky or gritty soil
  • Set it where people will not brush against the sharp tips
  • Keep it out of lawn and flower bed irrigation
  • Remove offsets to share or let the clump fill in

Through the seasons

Water a new plant a few times in its first warm season, then cut back. Established plants need occasional to little irrigation, and they look most colorful when kept on the dry side in full sun. Flower spikes are infrequent and tall, rising 6 to 8 feet with reddish green flowers. Hard frost below about 15 degrees F can harm it. WUCOLS rates thread leaf agave very low water on the north-central coast, in the Central Valley, in South Inland and in both deserts. On the south coast it carries a low water rating.

In pots

Thread leaf agave is an ideal pot plant, staying small and tidy for years. Use a gritty cactus mix in a pot with a large drainage hole. Water only when the mix is dry all the way through, then let it drain. In summer heat, that may mean a soak every week or two. Never leave water in the saucer. In winter, water very little, especially in cool, damp weather.

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
0.200.400.590.790.04JAN0.07FEB0.11MAR0.15APR0.21MAY0.25JUN0.27JUL0.24AUG0.18SEP0.12OCT0.06NOV0.03DEC0.200.400.590.790.04JFM0.15AMJ0.27JAS0.12OND
Gallons per square foot per month, Central Valley. Peak 0.27 in Jul, 1.71 a year.

Monthly water need by climate zone

Thread Leaf Agave: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.040.040.310.080.070.08
Feb0.050.070.320.090.090.09
Mar0.090.110.460.130.150.15
Apr0.120.150.560.160.190.2
May0.150.210.640.20.240.24
Jun0.160.250.690.230.290.28
Jul0.160.270.790.250.30.29
Aug0.150.240.740.230.280.26
Sep0.120.180.60.190.210.21
Oct0.090.120.460.130.150.15
Nov0.050.060.330.090.090.1
Dec0.030.030.260.070.070.07
Year1.21.716.21.842.132.11

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 thread leaf agave. 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 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 JulyCentury PlantAgave spp. & cvs.very 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 thread leaf agave, 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 thread leaf agave in summer?

In July, established thread leaf agave needs about 0.2 gallons in the Central Valley, 0.6 gallons on the south coast 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 thread leaf agave need per day?

In July in the Central Valley, established thread leaf agave 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 thread leaf agave change across California?

Yes. WUCOLS rates thread leaf agave 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, low water 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.

Why is my thread leaf agave turning red?

Leaves often show red tones when the plant is water stressed in full sun. That is normal and attractive. It is a sign of a dry, sunny site.

Is thread leaf agave poisonous?

It may be poisonous. The leaf tips are also sharp. Keep it away from paths and play areas.

How big does thread leaf agave get?

Each rosette grows about a foot tall and 15 to 24 inches wide. Clumps reach about 3 feet across. It stays compact.

How cold hardy is thread leaf agave?

It is hardy to about 15 to 20 degrees F. Wet cold is a bigger risk than dry cold. Good drainage helps.

Does thread leaf agave flower often?

No, flowering is infrequent. When it happens, a single unbranched spike towers over the rosette. Most of the time you enjoy the leaves.

More plant watering guides

Desert AgavePalmer AgaveButterfly AgaveSisalCentury PlantBlue AgaveUtah AgaveQueen Victoria Agave

Sources