WateringTimesWatering plan, $19
Oemleria cerasiformis, WUCOLS IV

How often to water osoberry in California

In July on the north-central coast, established osoberry 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. Osoberry is a California native deciduous shrub of forest edges from British Columbia to central California, also called Indian plum. It suckers into thickets 8 to 15 feet tall. In late winter or early spring, drooping clusters of small, fragrant, greenish white flowers open before the leaves. Female plants follow with small purple, plum-like fruits.

ShrubCalifornia nativeRated for 3 of 6 zones

How often to water osoberry, 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 osoberry 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

  • Leaves on osoberry wilting in summer while the soil is dry a few inches down mean it needs water
  • Leaves scorching at the edges in hot sun point to too little shade or water
  • Pale, yellowed leaves in shallow chalky soil point to chlorosis, not thirst
  • Suckers spreading widely in moist soil show it has plenty of water

How to water it

  • Water deeply under the canopy when the soil dries a few inches down
  • Plant in cool sun, part shade or shade in humus-rich soil
  • Mulch with leaf litter to keep the root zone cool
  • Remove excess suckers to keep the thicket in bounds
  • Cut it back hard to renew old plants

Through the seasons

Water a new shrub regularly through its first summer. Established plants want steady moisture on the north-central coast and less water farther south. It flowers before leafing out in late winter or early spring and drops its leaves in fall. Winter rain usually covers the bare months. WUCOLS rates osoberry moderate water on the north-central coast. The south coast and South Inland carry the same low water rating. WUCOLS has not evaluated it for the Central Valley, the high desert or the low desert.

In pots

Osoberry can live in a large container for a few years in a shady corner, where its early flowers are easy to enjoy. Use a humus-rich mix that drains well. Water when the top couple of inches dry, until it drains through. In summer, check every few days. Empty the saucer. Remove suckers as they appear. While it is bare in winter, water only when the mix dries.

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

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

Monthly water need by climate zone

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.37–0.310.31––
Feb0.53–0.320.35––
Mar0.87–0.460.52––
Apr1.18–0.560.64––
May1.46–0.640.78––
Jun1.61–0.690.92––
Jul1.61–0.791––
Aug1.49–0.740.93––
Sep1.24–0.60.74––
Oct0.87–0.460.53––
Nov0.47–0.330.36––
Dec0.31–0.260.27––
Year12–6.27.37––

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 not evaluated in the Central Valley, like osoberry. 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 osoberry, 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 osoberry in summer?

In July, established osoberry in loam needs a deep watering 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 osoberry need per day?

In July on the north-central coast, established osoberry 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 osoberry change across California?

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

Is osoberry a California native?

Yes, it is native from southern British Columbia south into central California. It is also called Indian plum or Oregon plum. It suits woodland gardens.

When does osoberry bloom?

Its drooping, fragrant flower clusters open in late winter or early spring. They appear before the leaves. That makes it an early sign of spring.

Why does my osoberry have no fruit?

Male and female flowers grow on separate plants. Only females make the plum-like fruits. You need both nearby for fruit.

Does osoberry spread?

Yes, it suckers and forms thickets 10 to 15 feet wide. In moist soil it suckers even more. Remove excess suckers to restrict it.

Can I cut osoberry back hard?

Yes, it can be cut back hard to renew it. Take old stems down to the base. New shoots rise from the roots.

More plant watering guides

Umbrella CatalpaTurkish HazelHardy CyclamenFine-Leafed MalleeCandelillaMoroccan MoundSeguier's SpurgeGreat Blanket Flower

Sources