WateringTimesWatering plan, $19
Carpinus japonica, WUCOLS IV

How often to water Japanese hornbeam in California

In July on the north-central coast, established Japanese hornbeam in loam needs a deep watering about every 13 days: about 55 gallons each time under a 10 foot canopy, about 29 gallons a week. Japanese hornbeam is a small to medium deciduous tree from Japan that grows slowly to about 20 to 30 feet in gardens. Its deep, parallel veins give the leaves a quilted look, and hanging catkins appear in spring. It handles heavy shade, which makes it a fine understory tree, and it adapts to a wide range of soils.

TreeRated for 1 of 6 zones

How often to water Japanese hornbeam, 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 Japanese hornbeam 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

  • Soil dry 4 inches down under the canopy in summer tells you Japanese hornbeam wants a deep watering
  • Leaves curling or browning at the edges in a hot spell can indicate thirst
  • Leaves dropping early in late summer can follow a long dry stretch
  • White powdery coating on leaves points to powdery mildew rather than water stress

How to water it

  • Water at the edge of the canopy with drip or a slow hose
  • Soak the soil a foot or more deep, then let the top few inches dry
  • Plant in part to full shade, though it tolerates full sun
  • Spread mulch over the root zone, kept off the trunk
  • Use it as a lawn tree or under taller trees

Through the seasons

Give a young tree regular deep water through its first few summers. Once roots spread, it needs less frequent soaks, though dry heat can stress its leaves. It leafs out in spring with catkins, and small nutlets form from late summer into fall. On the north-central coast, WUCOLS rates Japanese hornbeam moderate water. WUCOLS marks it as not suited to South Inland, and has not evaluated it for the Central Valley, the south coast, the high desert or the low desert.

In pots

Japanese hornbeam grows slowly enough to live in a large container for some years. Choose a wide, heavy pot and a well-drained mix. Water when the top couple of inches are dry, and soak until water runs out. In summer, a pot can dry within a few days, so check it often. Do not leave water in the saucer. In winter, when the tree is leafless, water only when the mix has dried.

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

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

Monthly water need by climate zone

Japanese Hornbeam: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.37–––––
Feb0.53–––––
Mar0.87–––––
Apr1.18–––––
May1.46–––––
Jun1.61–––––
Jul1.61–––––
Aug1.49–––––
Sep1.24–––––
Oct0.87–––––
Nov0.47–––––
Dec0.31–––––
Year12–––––

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 Japanese hornbeam. Plants that drink alike can share one valve and one schedule.

Hawthorn MapleAcer crataegifoliumnot rated, Central Valleyno Central Valley ratingMountain MapleAcer glabrumnot rated, Central Valleyno Central Valley ratingMiyabe MapleAcer miyabeinot rated, Central Valleyno Central Valley ratingEverglades PalmAcoelorraphe wrightiinot rated, Central Valleyno Central Valley ratingPink CedarAcrocarpus fraxinifoliusnot rated, Central Valleyno Central Valley ratingYellowwoodAfrocarpus falcatus (Podocarpus falcatus)not rated, Central Valleyno Central Valley ratingNew Caledonian PineAraucaria columnaris (A. cookii)not rated, Central Valleyno Central Valley ratingFormosa Sugar PalmArenga englerinot rated, Central Valleyno Central Valley ratingNeemAzadirachta indicanot rated, Central Valleyno Central Valley ratingBismarck PalmBismarckia nobilisnot rated, Central Valleyno Central Valley ratingAmerican HornbeamCarpinus caroliniananot rated, Central Valleyno Central Valley ratingAmerican YellowwoodCladrastis kentukeanot rated, Central Valleyno Central Valley ratingPagoda DogwoodCornus alternifolianot rated, Central Valleyno Central Valley ratingGiant DogwoodCornus controversanot rated, Central Valleyno Central Valley ratingButterfly PalmDypsis lutescens (Areca)not rated, Central Valleyno Central Valley ratingAbyssinian Coral TreeErythrina abyssinicanot 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 Japanese hornbeam, 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 much water does Japanese hornbeam need per day?

In July on the north-central coast, established Japanese hornbeam needs about 4.1 gallons a day under a 10 foot canopy and about 16 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 Japanese hornbeam change across California?

Yes. WUCOLS rates Japanese hornbeam separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, not evaluated in the Central Valley zone, not evaluated in the South Coastal zone, not suited to this region 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.

Can Japanese hornbeam grow in shade?

Yes, it tolerates heavy shade and makes a good understory tree. It prefers part to full shade. It also tolerates full sun.

How big does Japanese hornbeam get?

In gardens it usually reaches 20 to 30 feet. It grows slowly. It suits smaller yards.

What problems affect Japanese hornbeam?

It has no serious pests or diseases. Powdery mildew, leaf spots, cankers and twig blight can occur. Water at the base and keep air moving.

Is Japanese hornbeam deciduous?

Yes, it drops its leaves in fall. Bare winter branches show off its grayish-brown bark. Water rarely while it is bare.

What soil does Japanese hornbeam need?

It tolerates a wide range of soil types. Good drainage matters more than soil type. Mulch helps hold moisture.

More plant watering guides

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Sources