WateringTimesWatering plan, $19
Aesculus californica, WUCOLS IV

How often to water California buckeye in California

In July in the Central Valley, established California buckeye in loam needs a deep soak only about once a month or less: about 55 gallons each time under a 10 foot canopy. California buckeye is a native deciduous tree or large shrub of the coast ranges and Sierra foothills, usually 15 to 20 feet in gardens. Its crown is broad and flattened, and its bark is silvery gray. In late spring, upright clusters of sweet-scented creamy white flowers cover it, followed by large, shiny brown seeds in fall. All parts may be poisonous.

TreeCalifornia nativeRated for 4 of 6 zones

How often to water California buckeye, month by month

Your city
Canopy width
10 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 buckeye 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 under the branches, 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 canopy width

A tree with its canopy width marked across the widest branches and the circle under it shaded blue

Measure across the branches, from the tips of the outer leaves on one side to the tips on the other. A tape works, or pace it out.

Water the whole circle under the branches, shown in blue. The gallons here cover that circle.

A wider canopy means more gallons each watering, not more waterings. While the tree is young, measure again each spring.

How to tell it needs water

  • Leaves yellowing and dropping in summer is the normal summer dormancy, not distress
  • A young tree wilting in its first summer heat means it can use a deep soak
  • Leaves holding green into fall show the tree has had occasional summer water
  • Yellowing with dieback near lawn sprinklers points to too much water

How to water it

  • Water a young tree deeply a few times through its first summers
  • Once established, water occasionally or not at all
  • Plant in full sun to light shade in well-drained soil
  • Accept summer leaf drop, or water occasionally to keep leaves into fall
  • Keep children and pets from eating the seeds

Through the seasons

Water a young tree through its first couple of summers. Established trees need occasional summer water or none at all. They often go summer deciduous in dry or hot weather, sometimes by late spring, and occasional irrigation keeps leaves on into fall. New leaves in early spring are apple green, and flowers follow in late spring. WUCOLS rates California buckeye very low water on the north-central coast, in the Central Valley and on the south coast. In South Inland it carries a low water rating. WUCOLS marks it as not suited to the high desert or the low desert.

In pots

California buckeye belongs in the ground, but its big seed sprouts easily in a tall, deep pot. Use a well-drained mix. Water when the top few inches dry, then let it drain fully. In summer, check every few days, and expect a potted seedling to drop leaves early if it dries. Keep the saucer empty. In winter, rain usually covers it. Plant the seedling out while it is still small.

1 Your climate zone six WUCOLS zones, each from its own reference city
0.27gal per sq ft in JulyVery low water use in the Central Valley zone
A year
1.71 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.250.500.751.00.04JAN0.07FEB0.11MAR0.15APR0.21MAY0.25JUN0.27JUL0.24AUG0.18SEP0.12OCT0.06NOV0.03DEC0.250.500.751.00.04JFM0.15AMJ0.27JAS0.12OND
Gallons per square foot per month, Central Valley. Peak 0.27 in Jul, 1.71 a year.

Monthly water need by climate zone

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.040.040.080.31––
Feb0.050.070.080.35––
Mar0.090.110.110.52––
Apr0.120.150.140.64––
May0.150.210.160.78––
Jun0.160.250.170.92––
Jul0.160.270.21––
Aug0.150.240.190.93––
Sep0.120.180.150.74––
Oct0.090.120.110.53––
Nov0.050.060.080.36––
Dec0.030.030.070.27––
Year1.21.711.557.37––

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 very low water in the Central Valley, like California buckeye. Plants that drink alike can share one valve and one schedule.

Oak TreesQuercus agrifoliavery low water, Central Valley0.27 gal/sq ft in JulySalt CedarTamarix aphyllavery low water, Central Valley0.27 gal/sq ft in JulyPearl AcaciaAcacia podalyriifoliavery low water, Central Valley0.27 gal/sq ft in JulyMexican Palo VerdeParkinsonia aculeatavery low water, Central Valley0.27 gal/sq ft in JulyFoothill PinePinus sabinianavery low water, Central Valley0.27 gal/sq ft in JulyInterior Live OakQuercus wislizenivery low water, Central Valley0.27 gal/sq ft in JulyBlue OakQuercus douglasiivery low water, Central Valley0.27 gal/sq ft in JulyNuttall's Scrub OakQuercus dumosavery low water, Central Valley0.27 gal/sq ft in JulyTree of HeavenAilanthus altissimavery low water, Central Valley0.27 gal/sq ft in JulyOleanderNerium oleander ssp. & cvs.very low water, Central Valley0.27 gal/sq ft in JulyAgaveAgave americana (and thick-leaved relatives)very low water, Central Valley0.27 gal/sq ft in JulyCactusOpuntia spp. & cvs. (CA natives and non-natives)very low water, Central Valley0.27 gal/sq ft in JulySpanish BroomSpartium junceumvery low water, Central Valley0.27 gal/sq ft in JulyBig SagebrushArtemisia tridentatavery low water, Central Valley0.27 gal/sq ft in JulyCalifornia PoppyEschscholzia californicavery low water, Central Valley0.27 gal/sq ft in JulyCalifornia Scrub OakQuercus berberidifoliavery low water, Central Valley0.27 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 buckeye, 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 buckeye in summer?

In July, established California buckeye in loam needs a deep watering about once a month or less in the Central Valley, about once a month or less 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 buckeye need per day?

In July in the Central Valley, established California buckeye needs about 0.7 gallons a day under a 10 foot canopy and about 2.7 gallons a day under a 20 foot canopy. 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 buckeye change across California?

Yes. WUCOLS rates California buckeye separately for each of the six California climate zones: very low water in the North-Central Coastal zone, very low water in the Central Valley zone, very 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, not suited to this region in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Why is my California buckeye losing leaves in summer?

It naturally goes summer deciduous in response to dry or hot conditions. That can start in late spring. It is normal, not a sign of dying.

Can I keep California buckeye green all summer?

Occasional summer irrigation keeps it in leaf into fall. It is not required. Many gardeners enjoy the summer silhouette.

Is California buckeye poisonous?

It may be poisonous, and the seeds should not be eaten. Keep children and pets away from fallen seeds. Wear gloves when handling them.

When does California buckeye bloom?

It blooms in late spring with upright clusters of fragrant, creamy white flowers. Some trees show pink. The clusters are 6 to 12 inches long.

How big does California buckeye get?

In most gardens it reaches 15 to 20 feet, but it can grow to 40 feet. It often spreads wider than it is tall. Leave room.

More plant watering guides

SisalCentury PlantBlue AgaveUtah AgaveQueen Victoria AgaveCreosote BushPurple SageBlack Sage

Sources