WateringTimesWatering plan, $19
Artemisia arborescens, WUCOLS IV

How often to water large wormwood in California

In July on the north-central coast, established large wormwood in loam needs a deep soak only about once a month or less: about 8.8 gallons each time for a plant 4 feet across. Large wormwood is a fast, dense evergreen shrub from the rocky Mediterranean coast, 4 to 6 feet tall and wide. Its finely divided, aromatic foliage is silvery white. Small dull yellow flowers appear in late spring. It handles heat, drought, wind and salt air, and once established it needs only an occasional deep watering in well-drained soil.

ShrubRated for 5 of 6 zones

How often to water large wormwood, month by month

Your city
Plant width
4 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 large wormwood 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

  • A young large wormwood whose soil is dry a hand's depth down in its first summer is ready for a drink
  • Feathery silver leaves shriveling and shedding from the inner branches in a heat wave signal a long dry spell
  • Lanky, sprawling growth that splits open points to rich soil or too much water
  • Mushy, darkened stems at ground level over damp soil mean the roots are staying too wet

How to water it

  • Aim a slow trickle at the soil around the main stems, leaving the silver foliage dry
  • Give a long soak, then wait until the ground is dry several inches down before the next
  • Choose full sun to light shade and fast-draining ground, such as a slope or gravel bed
  • Keep it apart from lawns and beds on frequent irrigation
  • Shear lightly after bloom to keep it dense

Through the seasons

Water a new plant regularly until it puts on fresh growth, then shift to occasional deep soaks. Established shrubs take heat, drought, wind and salt air in stride. It stays evergreen with no tip damage to about 25 degrees F and is cold hardy to around 18 degrees F. For the north-central coast, the south coast and South Inland, WUCOLS lists large wormwood as low water. Both desert regions, high and low, raise that to a moderate water rating. The Central Valley has not been evaluated.

In pots

Large wormwood makes a bold silver accent in a big terracotta pot of gritty mix. Push a finger in, and add water only once the top two inches are dry. Pour until it flows from the holes, then let the pot drain fully. Under a hot summer sun the mix can dry out within days. Do not let water sit in a saucer underneath. Trim lightly after flowering to keep it compact. Through winter, rain often does the job, so water sparingly.

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

WUCOLS lists Large Wormwood as not evaluated for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Large Wormwood: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.15–0.310.310.740.78
Feb0.21–0.320.350.930.93
Mar0.35–0.460.521.461.52
Apr0.47–0.560.641.891.95
May0.58–0.640.782.392.45
Jun0.64–0.690.922.852.79
Jul0.64–0.7913.042.85
Aug0.6–0.740.932.792.6
Sep0.5–0.60.742.142.08
Oct0.35–0.460.531.461.49
Nov0.19–0.330.360.930.96
Dec0.12–0.260.270.650.68
Year4.8–6.27.3721.2721.08

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 not evaluated in the Central Valley, like large wormwood. Plants that drink alike can share one valve and one schedule.

Formosa Sugar PalmArenga englerinot rated, Central Valleyno Central Valley ratingChilean Feather BambooChusquea culeou (C. breviglumis)not rated, Central Valleyno Central Valley ratingBlackbrushColeogyne ramosissimanot rated, Central Valleyno Central Valley ratingGlaucous Scorpion VetchCoronilla valentina glaucanot rated, Central Valleyno Central Valley ratingWillowleaf CotoneasterCotoneaster salicifoliusnot rated, Central Valleyno Central Valley ratingMadagascar SagoCycas thouarsii (SHADE)not rated, Central Valleyno Central Valley ratingIrish HeathDaboecia cantabricanot rated, Central Valleyno Central Valley ratingButterfly PalmDypsis lutescens (Areca)not rated, Central Valleyno Central Valley ratingUmbrella BambooFargesia murielaenot rated, Central Valleyno Central Valley ratingBlue Fountain BambooFargesia nitida (Sinarundinaria nitida) (BAMBOO)not rated, Central Valleyno Central Valley ratingPrickly HeathGaultheria mucronata (Pernettya mucronata)not rated, Central Valleyno Central Valley ratingOtterbossieGossypium harknessiinot rated, Central Valleyno Central Valley ratingBox-leaved HollyIlex crenatanot rated, Central Valleyno Central Valley ratingBellyache BushJatropha gossypiifolianot rated, Central Valleyno Central Valley ratingMountain LaurelKalmia latifolianot rated, Central Valleyno Central Valley ratingBarbados CherryMalpighia glabranot 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 large wormwood, 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 large wormwood in summer?

In July, established large wormwood in loam needs a deep watering 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 large wormwood need per day?

In July on the north-central coast, established large wormwood needs about 0.3 gallons a day for a plant 4 feet across and about 1.0 gallons a day for a plant 8 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 large wormwood change across California?

Yes. WUCOLS rates large wormwood separately for each of the six California climate zones: low water in the North-Central Coastal zone, not evaluated in the Central Valley zone, low water in the South Coastal zone, low water in the South Inland zone, moderate water in the High and Intermediate Desert zone, moderate water in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

How is large wormwood different from Powis Castle?

Large wormwood is a much bigger shrub than Powis Castle. Its leaves are larger and whiter with more rounded lobes. Both like the same lean, dry soil.

Is large wormwood good near the coast?

Yes, it tolerates wind and salt air well. It grows naturally on rocky Mediterranean coasts. Give it full sun and fast drainage.

Do deer eat large wormwood?

It is deer tolerant. Wet soil is a bigger risk than deer.

How cold can large wormwood get?

It is hardy to at least 18 degrees F and stays evergreen without tip damage to about 25 degrees F. Hard frost can mark the tips. Prune damaged tips in spring.

Does large wormwood flower?

Yes, small dull yellow flower clusters appear in late spring. They are not showy. Grow it mainly for its silver foliage.

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Sources