WateringTimesWatering plan, $19
Quercus durata, WUCOLS IV

How often to water leather oak in California

In July in the Central Valley, established leather oak in loam needs a deep watering about every 20 days: about 8.8 gallons each time for a plant 4 feet across, about 3.0 gallons a week. Leather oak is a slow-growing evergreen shrub oak native to California's coast ranges and Sierra foothills, mostly on dry, rocky serpentine slopes in chaparral. Its small, leathery, dark green leaves curl under at the edges and carry a golden fuzz beneath. Once rooted it lives on very little water, and summer wetting near its base invites root rot rather than growth.

ShrubCalifornia nativeRated for 4 of 6 zones

How often to water leather oak, 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 leather oak 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 4 inches down at the edge of a young leather oak's root ball in its first summer means it is ready for a deep soak
  • New shoots wilting at the tips while the soil around a young plant is dry point to thirst
  • Clusters of honey-colored mushrooms at the base point to oak root fungus, which thrives in soil kept wet in summer
  • Thinning foliage and twig dieback over regularly watered soil call for a check of the root collar for rot
  • Leaf edges rolled under are normal for leather oak and do not signal drought stress

How to water it

  • Water a young leather oak slowly over its root ball and the soil just beyond it, then widen the ring as roots spread
  • Keep the root collar dry in summer, and never aim a sprinkler at the base of the stems
  • Plant in lean, rocky or gritty soil, and use clay only where water drains away freely
  • Spread a deep layer of mulch around the plant, kept a few inches back from the stems
  • Keep lawn and thirsty bedding plants out from under its canopy

Through the seasons

Give a new leather oak deep soakings through its first summers, tapering as roots reach into native soil. A mature plant that has never been irrigated should be left dry. The leaves stay on all year, and small greenish flowers appear in spring. Winter rain covers the cool months on the coast and in the Central Valley. In summer, keep water away from the base, since native oaks evolved without it. WUCOLS rates leather oak very low water on the north-central coast. It rates low water in the Central Valley, on the south coast and in South Inland. WUCOLS has not evaluated it for the high desert or the low desert.

In pots

Leather oak grows slowly and takes well to a container, and it makes a fine bonsai. Use a lean, gritty mix rather than rich potting soil, in a pot with open drainage holes. Check 2 inches down every few days in summer heat. Water until it runs from the bottom, then empty the saucer so the roots never sit wet. Young plants in nursery cans have come through hard frost well. In winter, rain may be enough for a pot left outdoors, so feel the mix before adding more.

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
0.270.540.801.10.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.270.540.801.10.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

Leather Oak: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.040.160.310.31––
Feb0.050.260.320.35––
Mar0.090.430.460.52––
Apr0.120.610.560.64––
May0.150.830.640.78––
Jun0.160.990.690.92––
Jul0.161.070.791––
Aug0.150.950.740.93––
Sep0.120.720.60.74––
Oct0.090.470.460.53––
Nov0.050.220.330.36––
Dec0.030.140.260.27––
Year1.26.846.27.37––

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 low water in the Central Valley, like leather oak. Plants that drink alike can share one valve and one schedule.

LavenderLavandula spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRosemaryRosmarinus officinalislow water, Central Valley1.07 gal/sq ft in JulyBougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyOlive TreesOlea europaea ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyCrape MyrtleLagerstroemia spp., hybrids & 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 JulyAloeAloe spp. & cvs.low 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 JulySagebrushArtemisia spp. (shrubby)low water, Central Valley1.07 gal/sq ft in JulyWild PrivetLigustrum vulgarelow water, Central Valley1.07 gal/sq ft in JulyCoralberrySymphoricarpos orbiculatus (SHADE)low water, Central Valley1.07 gal/sq ft in JulySydney Golden WattleAcacia longifolialow water, Central Valley1.07 gal/sq ft in JulyBlue Leaf WattleAcacia salignalow 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 leather oak, 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 leather oak in summer?

In July, established leather oak 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 leather oak need per day?

In July in the Central Valley, established leather oak needs about 0.4 gallons a day for a plant 4 feet across and about 1.7 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 leather oak change across California?

Yes. WUCOLS rates leather oak separately for each of the six California climate zones: very 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 evaluated 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.

Does leather oak need serpentine soil?

No. It grows mostly on serpentine in the wild, but garden soils work if they are low in nutrients and drain well. It tolerates clay under those conditions.

How big does leather oak get?

It usually reaches 3 to 12 feet tall and about as wide, often around 8 feet. Growth is slow. It can stay a mounding shrub or be pruned into a small tree.

Can I use leather oak as a hedge?

Yes. It is used for hedges and for holding soil on banks. Its slow growth means a hedge takes years to fill in.

Can I grow leather oak from an acorn?

Yes, that is how it is propagated. Sow fresh acorns outdoors in fall. To hold them for spring sowing, chill them first.

What can I plant under leather oak?

Pick dry-summer chaparral plants such as manzanita, ceanothus and toyon. Boulders and a thick mulch also suit it. Skip anything that needs summer water near its base.

Should I water an old leather oak that has never been watered?

No. Do not start irrigating a mature, established oak that has always lived without it. Summer water near the base can bring on oak root fungus.

More plant watering guides

Bottle BrushEuropean Gray SedgeRiver She-OakCommon HackberryMediterranean Fan PalmWintersweetSpurge OliveGround Morning Glory

Sources