WateringTimesWatering plan, $19
Achillea millefolium (CA native cultivars), WUCOLS IV

How often to water California native yarrow in California

In July in the Central Valley, established California native yarrow in loam needs a deep watering about every 20 days: about 2.2 gallons each time for a plant 2 feet across, about 0.8 gallons a week. Yarrow is a ferny, aromatic perennial native across much of North America, including California. Flat clusters of tiny white flowers rise on stems 1 to 3 feet tall. Native selections range from upright to mat-forming, some with pink flowers, and they spread by rhizomes and seed. It tolerates poor soil, drought and some salt, and it rots in soggy ground.

Ground coverPerennialCalifornia nativeRated for 6 of 6 zones

How often to water California native yarrow, 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 California native yarrow 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 3 inches down under the clump in summer signals yarrow can use a soak
  • Ferny leaves turning gray and limp after a long dry spell can indicate thirst
  • Flower stems browning early in summer can follow drought during bloom
  • Yellowing patches and rotting crowns in wet, heavy soil point to root rot from overwatering

How to water it

  • Water the planting with a soaker or low spray, wetting the whole spreading patch
  • Soak several inches down, then let the soil dry before watering again
  • Plant in full sun in well-drained soil, even poor or sandy ground
  • Shear after bloom if you use it as a lawn alternative
  • Deadhead to prolong bloom and limit spread by seed

Through the seasons

Water a new yarrow planting regularly until it begins to spread, then cut back to occasional deep soaks. Established plants tolerate drought, poor soil and some salt, and wet soil causes root rot. Flowers run from late spring into fall, and deadheading extends them. On the north-central coast and in the Central Valley, WUCOLS rates California native yarrow low water. The south coast, South Inland, the high desert and the low desert carry the same low water rating.

In pots

Yarrow grows well in a wide pot, which also keeps its spreading rhizomes in check. Use well-drained mix and water once the top couple of inches have dried, letting the excess run off. In summer heat, check the pot every few days. Empty the saucer each time. Shear spent flower stems to keep it tidy and blooming. In winter, rain is often enough, so check the mix before adding water.

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

California Native Yarrow: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.310.310.30.31
Feb0.210.260.320.350.370.37
Mar0.350.430.460.520.580.61
Apr0.470.610.560.640.760.78
May0.580.830.640.780.950.98
Jun0.640.990.690.921.141.12
Jul0.641.070.7911.221.14
Aug0.60.950.740.931.121.04
Sep0.50.720.60.740.860.83
Oct0.350.470.460.530.580.6
Nov0.190.220.330.360.370.38
Dec0.120.140.260.270.260.27
Year4.86.846.27.378.518.43

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 California native yarrow. Plants that drink alike can share one valve and one schedule.

BougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyAgapanthusAgapanthus orientalislow water, Central Valley1.07 gal/sq ft in JulyGeraniumsPelargonium x hortorum and 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 JulyIrisesIris germanicalow 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 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 JulySagebrushArtemisia spp. (shrubby)low 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 July
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes California native yarrow, 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 California native yarrow in summer?

In July, established California native yarrow in loam needs a deep watering about every 20 days in the Central Valley, about every 27 days 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 California native yarrow need per day?

In July in the Central Valley, established California native yarrow 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 California native yarrow change across California?

Yes. WUCOLS rates California native yarrow 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, 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.

Can yarrow replace a lawn?

Yes, it is used as a lawn alternative in low foot traffic areas. It can be mowed after bloom to keep it low. Water the patch deeply but rarely.

Does yarrow spread?

Yes, it spreads by rhizomes and seed, sometimes aggressively. Divide clumps easily to control it. Deadhead to limit seedlings.

Is yarrow safe for pets?

Avoid planting it where pets graze. Wear gloves to prevent skin irritation when handling it. Wash hands after cutting flowers.

What yarrow is native to California?

The species grows wild across California, and native selections include pink-flowered forms from the Channel Islands. They vary from upright to mat-forming. All share the same low water needs.

Does yarrow attract pollinators?

Yes, its flat flower clusters attract many pollinators. Bloom runs through summer. The flowers also cut and dry well.

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Sources