WateringTimesWatering plan, $19
Euphorbia rigida, WUCOLS IV

How often to water rigid spurge in California

In July in the Central Valley, established rigid spurge in loam needs a deep watering about every 14 days: about 1.5 gallons each time for a plant 2 feet across, about 0.8 gallons a week. Rigid spurge, Euphorbia rigida, is a Mediterranean evergreen perennial sold as gopher spurge. Thick upright stems carry fleshy, steel blue-green leaves in tight spirals, topped by chartreuse flower heads in late winter and spring. It forms a clump about 2 feet tall and 3 feet wide. Once rooted in, it wants only occasional water and sharp drainage.

PerennialSucculentRated for 5 of 6 zones

How often to water rigid spurge, 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 rigid spurge 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 foot 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 3 inches down at the edge of a newly planted clump in its first summer means it is time for a soak
  • Flower heads fading to reddish tan as the stems die back after bloom is normal, not a sign of thirst
  • Leaves taking on red tints in late fall is seasonal color and does not call for extra water
  • Wilting or yellowing stems while the soil stays wet point to root rot, which euphorbias suffer in soggy ground
  • A white powdery coating on leaves and flowers is powdery mildew, which more water will not fix

How to water it

  • Water a new plant at the base of the clump through its first two growing seasons, then cut back to occasional soaks
  • Plant in sandy, gravelly or rocky soil that drains freely, and avoid low spots where rain collects
  • Use a drip emitter beside the clump rather than spray, so the fleshy leaves stay dry
  • Spread gravel around the crown rather than a thick layer of bark mulch
  • Move the emitter outward as the clump widens with new shoots from its base

Through the seasons

Water a new rigid spurge through dry spells in its first two growing seasons, until its roots settle. After that it needs only occasional summer water. The plant is evergreen and blooms in late winter and spring. After bloom, cut the flowered stems to the base, and new shoots will rise from the crown. It tends to be shorter lived where winters are warm. WUCOLS rates it low water on the north-central coast, in the Central Valley, on the south coast, in South Inland and in the low desert. Winter rain covers the cool months on the coast and in the Central Valley. WUCOLS marks it as not suited to the high desert.

In pots

Rigid spurge works well as a patio container plant. Use a pot with a drainage hole and a gritty mix, about one part grit to three parts potting mix. Check the mix 2 inches down every few days in summer heat, and water when that layer is dry. Water until it runs from the holes, then empty the saucer. Potted plants need more regular water than plants in the ground, since the mix dries out faster. In winter, water only when the mix is dry, since cold, wet soil invites root 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
0.280.570.851.10.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.280.570.851.10.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

Rigid Spurge: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.310.31–0.31
Feb0.210.260.320.35–0.37
Mar0.350.430.460.52–0.61
Apr0.470.610.560.64–0.78
May0.580.830.640.78–0.98
Jun0.640.990.690.92–1.12
Jul0.641.070.791–1.14
Aug0.60.950.740.93–1.04
Sep0.50.720.60.74–0.83
Oct0.350.470.460.53–0.6
Nov0.190.220.330.36–0.38
Dec0.120.140.260.27–0.27
Year4.86.846.27.37–8.43

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 16

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

AgapanthusAgapanthus orientalislow water, Central Valley1.07 gal/sq ft in JulyGeraniumsPelargonium x hortorum and cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyIrisesIris germanicalow 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 JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyYarrowAchillea millefolium (non-native hybrids)low water, Central Valley1.07 gal/sq ft in JulyMountain AlyssumAlyssum montanumlow water, Central Valley1.07 gal/sq ft in JulySilver SageSalvia argentealow water, Central Valley1.07 gal/sq ft in JulyPurple MulleinVerbascum phoeniceumlow water, Central Valley1.07 gal/sq ft in JulySilvery YarrowAchillea clavennaelow water, Central Valley1.07 gal/sq ft in JulyFern Leaf YarrowAchillea filipendulinalow water, Central Valley1.07 gal/sq ft in JulyCalifornia Native YarrowAchillea millefolium (CA native cultivars)low water, Central Valley1.07 gal/sq ft in JulyWoolly YarrowAchillea tomentosalow water, Central Valley1.07 gal/sq ft in JulyPerennial HollyhockAlcea rosea cvs.low 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 rigid spurge, 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 rigid spurge in summer?

In July, established rigid spurge in loam needs a deep watering about every 14 days in the Central Valley, about every 18 days on the south coast and about every 14 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 rigid spurge need per day?

In July in the Central Valley, established rigid spurge needs about 0.1 gallons a day for a plant 2 feet across and about 0.4 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 rigid spurge change across California?

Yes. WUCOLS rates rigid spurge separately for each of the six California climate zones: low water in the North-Central Coastal zone, low water in the Central Valley zone, low water in the South Coastal zone, low water in the South Inland zone, not suited to this region 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 gopher spurge the same as rigid spurge?

Sometimes. Euphorbia rigida is listed under the name gopher spurge, but that name is more often used for Euphorbia lathyris, a different plant. Check the botanical name on the label before you buy.

Does gopher spurge really repel gophers?

It is said to repel gophers, which is how it got that name. Do not rely on it as gopher control. Grow it for its blue-green foliage and spring color instead.

Is rigid spurge poisonous?

Yes. All parts are toxic if eaten, and the milky sap can irritate skin and eyes. Wear gloves when you cut it back, and keep it away from children and pets.

Should I cut back rigid spurge after it flowers?

Yes. Cut each flowered stem to its base once the bracts fade to tan. That tidies the clump and stops most self-sowing, and new stems grow from the crown.

Does rigid spurge spread?

It seeds itself around, though it is not usually too weedy in gardens. Removing the spent flower stems keeps seedlings down. In parts of its native range it is counted as a weed.

Will rigid spurge grow near the coast?

Yes. It is salt tolerant and suits coastal gardens, gravel gardens, rock gardens and dry slopes. Deer tend to leave it alone.

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Sources