WateringTimesWatering plan, $19
Euphorbia trigona, WUCOLS IV

How often to water African milk tree in California

In July on the north-central coast, established African milk tree needs about 0.5 gallons a week for a plant 2 feet across. African milk tree is a branching, cactus-like succulent from central Africa. Its upright, three-sided green stems carry short paired spines and small teardrop leaves, and it can reach 6 to 12 feet in a candelabra shape. It needs well-drained soil and sparing water, and its milky sap is poisonous and irritating.

SucculentRated for 4 of 6 zones

How often to water African milk tree, 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 African milk tree 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

  • Soil dry 2 inches down beside the stems signals an African milk tree in the ground can take a soak
  • Stems looking thin, wrinkled or soft-sided after a long dry spell can indicate thirst
  • Stems browning and scarring where they sit against wet ground point to rot
  • Mushy, discolored stem bases over damp soil point to rot from overwatering

How to water it

  • Water at the base with a slow hose, keeping stems dry
  • Soak several inches down, then let the soil dry before watering again
  • Plant in sandy or loamy, fast-draining soil in partial sun
  • Keep it out of beds that are watered often
  • Give it bright light outdoors, with partial sun rather than harsh exposure

Through the seasons

Water a new plant lightly until roots grow into the soil, then water sparingly. It is evergreen and grows slowly, mostly in warm weather. Cold is its main risk, and wet, cold soil makes rot more likely. In the ground, it suits only the mildest frost-free gardens. WUCOLS rates African milk tree very low water on the south coast. It rates low water on the north-central coast, in South Inland and in the low desert. WUCOLS has not evaluated it for the Central Valley or the high desert.

In pots

African milk tree is most often grown in a pot of cactus or succulent mix. Water when the mix is dry 1 to 2 inches down, letting excess drain out. Water sparingly, since overwatering is the most common cause of trouble. Never leave water in the saucer. Bring pots indoors or under cover before nights drop below about 45 degrees F. Wear gloves when handling it.

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

WUCOLS lists African Milk Tree as not evaluated for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

African Milk Tree: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.15–0.080.31–0.31
Feb0.21–0.080.35–0.37
Mar0.35–0.110.52–0.61
Apr0.47–0.140.64–0.78
May0.58–0.160.78–0.98
Jun0.64–0.170.92–1.12
Jul0.64–0.21–1.14
Aug0.6–0.190.93–1.04
Sep0.5–0.150.74–0.83
Oct0.35–0.110.53–0.6
Nov0.19–0.080.36–0.38
Dec0.12–0.070.27–0.27
Year4.8–1.557.37–8.43

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 13

Rated not evaluated in the Central Valley, like African milk tree. Plants that drink alike can share one valve and one schedule.

Purple SpurgeEuphorbia dulcisnot rated, Central Valleyno Central Valley ratingGiant White YuccaYucca faxoniananot rated, Central Valleyno Central Valley ratingCandelillaEuphorbia antisyphiliticanot rated, Central Valleyno Central Valley ratingMoroccan MoundEuphorbia resiniferanot rated, Central Valleyno Central Valley ratingSeguier's SpurgeEuphorbia seguieriana niciciananot rated, Central Valleyno Central Valley ratingBanana YuccaYucca baccatanot rated, Central Valleyno Central Valley ratingSoaptree YuccaYucca elatanot rated, Central Valleyno Central Valley ratingMojave YuccaYucca schidigera (Yucca californica, Yucca mohavensis)not rated, Central Valleyno Central Valley ratingSpanish BayonetYucca aloifolianot rated, Central Valleyno Central Valley ratingSoapweed YuccaYucca glaucanot rated, Central Valleyno Central Valley ratingMountain YuccaYucca schottiinot rated, Central Valleyno Central Valley ratingEuphorbia candelabrumEuphorbia candelabrumnot rated, Central Valleyno Central Valley ratingThanksgiving CactusSchlumbergera (Zygocactus) truncata (truncates)not 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 African milk tree, 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 African milk tree in summer?

In July, established African milk tree needs about 0.1 gallons on the south coast and 0.7 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 African milk tree need per day?

In July on the north-central coast, established African milk tree needs about 0.1 gallons a day for a plant 2 feet across and about 0.3 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 African milk tree change across California?

Yes. WUCOLS rates African milk tree separately for each of the six California climate zones: low water in the North-Central Coastal zone, not evaluated in the Central Valley zone, very low water in the South Coastal zone, low water in the South Inland zone, not evaluated 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 African milk tree sap dangerous?

Yes, the milky sap is poisonous and can irritate skin and eyes. Wear gloves and eye protection when pruning. Keep it away from children and pets.

Is African milk tree a cactus?

No, it is a succulent in the spurge family that looks like a cactus. The milky sap is one way to tell. Its spines grow in pairs along the ridges.

How cold can African milk tree get?

It prefers warm temperatures, and outdoor plants should move inside before the cold arrives. Frost damages the stems. Keep it dry in cold weather.

Does African milk tree flower?

It rarely blooms in cultivation. In the wild it has small green or yellow flowers. Grow it for its form.

How do I propagate African milk tree?

Take stem cuttings or use air layering. Let cuttings dry before planting in gritty mix. Water lightly until they root.

More plant watering guides

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Sources