WateringTimesWatering plan, $19
Photinia glabra, WUCOLS IV

How often to water Japanese photinia in California

In July on the north-central coast, established Japanese photinia in loam needs a deep watering about every 13 days: about 8.8 gallons each time for a plant 4 feet across, about 4.6 gallons a week. Japanese photinia is an evergreen shrub or small tree from Japan and China. Its leathery leaves open bronze-red, then turn dark green, and white flower heads in late spring give way to red fruit. It wants moist soil that drains well and does poorly in wet ground. Water it at the soil, since wet leaves invite leaf spot.

ShrubRated for 3 of 6 zones

How often to water Japanese photinia, 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 Japanese photinia 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 3 to 4 inches down under the outer branches means a Japanese photinia is ready for a deep soak
  • Bronze-red new shoots that wilt in afternoon heat, with dry soil below, point to a thirsty root zone
  • Yellowing leaves over soil that stays wet for days point to overwatering, which this shrub handles poorly
  • Tiny reddish leaf spots with a dark red, purple or yellow halo are a fungal leaf spot spread by splashing water, not a sign of thirst

How to water it

  • Water Japanese photinia at the soil line with drip or a soaker hose, keeping spray off the leaves
  • Soak the root zone to about 18 inches, then let the top few inches dry before watering again
  • Plant in fertile, well-drained soil, and avoid low spots where rain water collects
  • Spread wood chip mulch under the shrub, kept back from the stems, and rake up fallen spotted leaves
  • Move drip emitters outward as the shrub widens so water reaches the roots under its outer leaves

Through the seasons

Give a new Japanese photinia deep soakings through its first summer, until roots grow out past the planting hole. Established plants handle short dry spells but are not drought proof. Spring brings the bronze-red flush of new leaves, and leaf spot is worst when that growth stays wet, so keep water at the soil then. As an evergreen it holds its leaves all winter, and winter rain covers the cool months on the coast. WUCOLS rates it moderate water on the north-central coast, the south coast and in South Inland. WUCOLS has not evaluated it for the Central Valley, the high desert or the low desert.

In pots

A young Japanese photinia can grow in a large container while pruning keeps it small. Use a pot with open drainage holes and a fertile mix that drains freely. Check the mix 2 inches down every few days in summer, and more often during South Inland heat. Water at the rim until it drains out the bottom, then empty the saucer so the roots never sit in water. Keep the leaves dry when you water. This is the least cold tolerant photinia, so move a potted plant out of cold wind in winter.

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

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

Monthly water need by climate zone

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.37–0.780.78––
Feb0.53–0.810.87––
Mar0.87–1.151.3––
Apr1.18–1.41.61––
May1.46–1.611.95––
Jun1.61–1.742.29––
Jul1.61–1.982.51––
Aug1.49–1.862.33––
Sep1.24–1.491.86––
Oct0.87–1.151.33––
Nov0.47–0.840.9––
Dec0.31–0.650.68––
Year12–15.518.41––

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 photinia. 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 Japanese photinia, 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 Japanese photinia in summer?

In July, established Japanese photinia in loam needs a deep watering about every 11 days on the south coast and about every 9 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 Japanese photinia need per day?

In July on the north-central coast, established Japanese photinia needs about 0.7 gallons a day for a plant 4 feet across and about 2.6 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 Japanese photinia change across California?

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

Why does my Japanese photinia have red spots on its leaves?

Tiny red spots that darken and enlarge are usually Entomosporium leaf spot, a fungus that can drop leaves early. Rain and sprinklers splash its spores onto new growth. Switch to drip, and remove spotted leaves from the plant and the ground.

Why do Japanese photinia flowers smell bad?

The scent of the late spring flowers divides people. Some compare it to hawthorn, while others find it unpleasant. Plant it away from windows and seating areas if the smell bothers you.

Are Japanese photinia berries edible?

No. The red fruits are ornamental and should not be eaten, by people or by pets. Wear gloves when you handle or prune the plant.

How big does Japanese photinia get?

It often reaches about 10 feet at maturity. An unpruned plant can eventually grow to about 20 feet. It works as a hedge or can be trained as a small tree.

Is Japanese photinia cold hardy?

It is the least cold tolerant of the photinias. Plant it where buildings or other shrubs shelter it from cold wind. Frost damage is not a sign of thirst, so check the soil before adding water.

Does Japanese photinia get fireblight?

Yes, fireblight is one of its listed diseases, along with leaf spot, powdery mildew, aphids and scale. Site it in sun or part shade with good air circulation. Water at the soil rather than with overhead spray.

More plant watering guides

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Sources