WateringTimesWatering plan, $19
Salix spp. (shrubs), WUCOLS IV

How often to water willow in California

In July in the Central Valley, established willow in loam needs a deep watering about every 5 days: about 8.8 gallons each time for a plant 4 feet across, about 12 gallons a week. Shrub willows are fast growing deciduous plants grown for their colorful buds or catkins, bright stems or twisted branches. Like tree willows, they come from wet ground along streams and in wetlands, and their roots are invasive. They do best in full sun with ample water and tolerate almost any soil.

ShrubRated for 5 of 6 zones

How often to water willow, 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 willow 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 2 to 3 inches down around a shrub willow signals that it needs a deep soak, since willows want steady moisture
  • Leaves yellowing and dropping early in summer heat can indicate a dry root zone
  • Leaf edges browning in hot, dry wind or salty soil can be leaf scorch rather than simple thirst
  • Sticky leaves, curled shoots or fine webbing point to aphids or spider mites, both common on willows
  • Wilting with dark, sunken bark at the base can indicate Phytophthora crown rot, so check drainage even for this water lover

How to water it

  • Water a shrub willow deeply across its whole root area, soaking the soil a foot or more down
  • Water again when the top couple of inches dry, keeping the root zone evenly moist through summer
  • Plant in full sun, ideally where natural moisture collects, such as a swale or pond edge
  • Keep plantings well away from pipes and foundations, since willow roots are invasive
  • Mulch the root zone to slow evaporation, and widen watering as the clump spreads

Through the seasons

Keep a new shrub willow evenly moist through its first season while roots spread. Established plants still need steady water through the warm months, since willows grow naturally in wet places. Leaves drop in fall, and colorful stems then stand out on the bare branches. WUCOLS rates willow high water on the north-central coast, in the Central Valley and on the south coast. South Inland and the high desert share that high water rating. WUCOLS has not evaluated it for the low desert. Winter rain often covers the leafless shrub on the coast and in the Central Valley.

In pots

Compact shrub willows can grow in a large container, which also keeps their roots away from pipes and foundations. Use a big pot with drainage holes and a mix that holds moisture. Check the mix daily in summer heat and water whenever the top inch is dry, since a potted willow dries fast. Water until it drains through. In winter the plant is leafless, so water only enough to keep the mix damp.

1 Your climate zone six WUCOLS zones, each from its own reference city
4.27gal per sq ft in JulyHigh water use in the Central Valley zone
A year
27.38 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
1.22.43.64.90.64JAN1.04FEB1.74MAR2.43APR3.32MAY3.97JUN4.27JUL3.82AUG2.88SEP1.88OCT0.89NOV0.55DEC1.22.43.64.90.64JFM2.43AMJ4.27JAS1.88OND
Gallons per square foot per month, Central Valley. Peak 4.27 in Jul, 27.38 a year.

Monthly water need by climate zone

Willow: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.60.641.241.241.19–
Feb0.841.041.291.391.49–
Mar1.391.741.842.082.33–
Apr1.882.432.232.583.03–
May2.333.322.583.123.82–
Jun2.583.972.783.674.56–
Jul2.584.273.174.024.86–
Aug2.383.822.983.724.46–
Sep1.982.882.382.983.42–
Oct1.391.881.842.132.33–
Nov0.740.891.341.441.49–
Dec0.50.551.041.091.04–
Year19.227.3824.829.4634.03–

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 high water in the Central Valley, like willow. Plants that drink alike can share one valve and one schedule.

HydrangeaHydrangea macrophylla & cvs.high water, Central Valley4.27 gal/sq ft in JulyBlueberriesVaccinium hybrids and cvs (CA native and non- native spp.)high water, Central Valley4.27 gal/sq ft in JulyShell GingerAlpinia zerumbethigh water, Central Valley4.27 gal/sq ft in JulyBog RosemaryAndromeda polifoliahigh water, Central Valley4.27 gal/sq ft in JulyBlood Twig DogwoodCornus sanguineahigh water, Central Valley4.27 gal/sq ft in JulyRed-veined EnkianthusEnkianthus campanulatushigh water, Central Valley4.27 gal/sq ft in JulyAbyssinian BananaEnsete ventricosumhigh water, Central Valley4.27 gal/sq ft in JulyClimbing HydrangeaHydrangea anomala petiolarishigh water, Central Valley4.27 gal/sq ft in JulySnowball HydrangeaHydrangea arborescenshigh water, Central Valley4.27 gal/sq ft in JulyLacecap HydrangeaHydrangea aspera villosahigh water, Central Valley4.27 gal/sq ft in JulyBrazilian Plume FlowerJusticia carneahigh water, Central Valley4.27 gal/sq ft in JulyBananaMusa spp. (shade in low desert)high water, Central Valley4.27 gal/sq ft in JulyVine MapleAcer circinatumhigh water, Central Valley4.27 gal/sq ft in JulyBig Leaf MapleAcer macrophyllumhigh water, Central Valley4.27 gal/sq ft in JulyWhite AlderAlnus rhombifoliahigh water, Central Valley4.27 gal/sq ft in JulyRed AlderAlnus rubra (Alnus oregona)high water, Central Valley4.27 gal/sq ft in July

Similar plants that need less water 16

Rated lower than willow in the Central Valley. Worth a look for a new bed or a lawn replacement.

RosesRosa hybrids..bushmoderate water, Central Valley2.67 gal/sq ft in JulyAzaleasRhododendron spp. (CA native and non-native spp.)moderate water, Central Valley2.67 gal/sq ft in JulyCamelliasCamellia japonica (SHADE IN DESERT)moderate water, Central Valley2.67 gal/sq ft in JulyGardeniasGardenia spp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBird of ParadiseStrelitzia reginae (shade in desert)moderate water, Central Valley2.67 gal/sq ft in JulyHibiscusHibiscus rosa-sinensismoderate water, Central Valley2.67 gal/sq ft in JulySago PalmCycas revolutamoderate water, Central Valley2.67 gal/sq ft in JulyStar JasmineTrachelospermum jasminoides and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyArborvitaeThuja occidentalis ssp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBambooBambusa spp.moderate water, Central Valley2.67 gal/sq ft in JulyLilacsSyringa hybrids (including Descanso hybrids)moderate water, Central Valley2.67 gal/sq ft in JulySpireaSpiraea spp. (CA native and non native spp.)moderate water, Central Valley2.67 gal/sq ft in JulyButterfly BushBuddleja davidii and hybridsmoderate water, Central Valley2.67 gal/sq ft in JulySageSalvia officinalis and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyRed BuckeyeAesculus paviamoderate water, Central Valley2.67 gal/sq ft in JulyWestern ServiceberryAmelanchier alnifoliamoderate water, Central Valley2.67 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 willow, 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 willow in summer?

In July, established willow in loam needs a deep watering about every 5 days in the Central Valley, about every 7 days on the south coast and about every 5 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 willow need per day?

In July in the Central Valley, established willow needs about 1.7 gallons a day for a plant 4 feet across and about 6.9 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 willow change across California?

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

Do willow roots damage pipes?

Willow roots are invasive and seek out water, so keep shrubs well away from pipes, septic systems and foundations. A large container or a distant, moist corner of the yard is a safer spot.

Why are shrub willows grown?

Gardeners plant most shrub types for showy catkins, stems in bright colors, or contorted branches. Their flexible branches also go into basketry and living fences. Pollinators and specialized bees visit the flowers.

Are willows invasive?

Some willow species are invasive weeds, and their seeds travel on cotton-like hairs carried by wind and water. Choose shrub types carefully. Keep them away from creeks and wild areas you do not want them to colonize.

Can you overwater a willow?

Willows grow naturally in wet ground, yet poorly drained soil can still lead to Phytophthora root and crown rot. In heavy clay, let the surface dry slightly between deep soakings.

What pests attack shrub willows?

Aphids, lace bugs, leaf beetles, spider mites and borers are common. Rust and cankers can also appear. Good watering reduces stress, but it will not stop all of these problems.

More plant watering guides

White Ginger LilyClimbing HydrangeaSnowball HydrangeaLacecap HydrangeaJapanese IrisRushBrazilian Plume FlowerCardinal Flower

Sources