WateringTimesWatering plan, $19
Fraxinus ornus, WUCOLS IV

How often to water flowering ash in California

In July in the Central Valley, established flowering ash in loam needs a deep watering about every 8 days: about 55 gallons each time under a 10 foot canopy, about 47 gallons a week. Flowering ash, also called manna ash, is a round-headed deciduous tree that reaches 40 to 50 feet. It is one of the few ashes with showy flowers, bearing fragrant clusters of creamy white blooms with or just after the spring leaves. It grows best in full sun and well-drained soil, with deep soakings through the dry months.

TreeRated for 3 of 6 zones

How often to water flowering ash, 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 flowering ash 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 to 6 inches down under the outer canopy signals that an established flowering ash needs a deep soak
  • Leaflets browning at the edges after hot, dry weather can accompany a dry root zone
  • Leaves dropping early in late summer can follow a long dry stretch, so check the soil before the next soak
  • Yellowing leaves over soil that stays soggy can indicate poor drainage around the roots
  • Old seed clusters hanging on into winter are normal and say nothing about water

How to water it

  • Water a young flowering ash over its root ball and a widening ring beyond it as roots spread
  • On an established tree, place water beneath the outer canopy and past the drip line rather than at the trunk
  • Soak slowly to wet the soil 18 inches or more, then let the upper several inches dry before the next soak
  • Plant in full sun and well-drained, neutral to alkaline soil
  • Mulch across the root area with wood chips, leaving the trunk base bare

Through the seasons

Water a new flowering ash deeply through its first two or three summers while roots spread. Established trees take deep soakings spaced well apart through the dry season. WUCOLS rates flowering ash moderate water on the north-central coast, in the Central Valley and in South Inland. WUCOLS has not evaluated it for the south coast, the high desert or the low desert. The tree leafs out and flowers in spring, then carries a full canopy through summer, when irrigation matters most. After leaf fall it is dormant, and winter rain usually covers it on the north-central coast and in the Central Valley.

In pots

Flowering ash grows into a 40 to 50 foot tree, so a container only suits a young tree before planting out. Choose a deep pot with open holes and a loam based mix that drains well. Check the mix 2 to 3 inches down every few days in summer heat, and water when it is dry there. Water until excess drains, then empty the saucer. After leaf fall, water lightly and only when the mix starts to dry. Move it into the ground while its roots are still young.

1 Your climate zone six WUCOLS zones, each from its own reference city
2.67gal per sq ft in JulyModerate water use in the Central Valley zone
A year
17.11 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.671.32.02.70.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.671.32.02.70.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Flowering Ash: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.4–0.78––
Feb0.530.65–0.87––
Mar0.871.09–1.3––
Apr1.181.52–1.61––
May1.462.08–1.95––
Jun1.612.48–2.29––
Jul1.612.67–2.51––
Aug1.492.39–2.33––
Sep1.241.8–1.86––
Oct0.871.18–1.33––
Nov0.470.56–0.9––
Dec0.310.34–0.68––
Year1217.11–18.41––

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 moderate water in the Central Valley, like flowering ash. Plants that drink alike can share one valve and one schedule.

Citrus TreesCitrus spp.moderate water, Central Valley2.67 gal/sq ft in JulyJapanese MapleAcer palmatummoderate water, Central Valley2.67 gal/sq ft in JulyAvocado TreesPersea americanamoderate water, Central Valley2.67 gal/sq ft in JulyMagnolia TreesMagnolia grandiflora ssp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyPalm TreesSyagrus romanzoffiana (Arecastrum romanzoffianum)moderate water, Central Valley2.67 gal/sq ft in JulyApple TreesMalus spp. (edible) e.g, 'Anna' (low chill variety for low desert)moderate water, Central Valley2.67 gal/sq ft in JulyPeach TreesPrunus spp. ediblemoderate water, Central Valley2.67 gal/sq ft in JulyPersimmon TreesDiospyros kakimoderate water, Central Valley2.67 gal/sq ft in JulyAmur MapleAcer ginnalamoderate water, Central Valley2.67 gal/sq ft in JulyFernleaf MapleAcer japonicummoderate water, Central Valley2.67 gal/sq ft in JulyBox ElderAcer negundomoderate water, Central Valley2.67 gal/sq ft in JulyNorway MapleAcer platanoidesmoderate water, Central Valley2.67 gal/sq ft in JulyRed MapleAcer rubrummoderate water, Central Valley2.67 gal/sq ft in JulyChinese MapleAcer truncatummoderate water, Central Valley2.67 gal/sq ft in JulyRed BuckeyeAesculus paviamoderate water, Central Valley2.67 gal/sq ft in JulyRed HorsechestnutAesculus x carneamoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

Rated lower than flowering ash in the Central Valley. Worth a look for a new bed or a lawn replacement.

Olive TreesOlea europaea ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyFig TreesFicus carica 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 JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyPomegranate TreesPunica granatumlow water, Central Valley1.07 gal/sq ft in JulyEucalyptusEucalyptus polyanthemoslow water, Central Valley1.07 gal/sq ft in JulyPine TreesPinus canariensislow water, Central Valley1.07 gal/sq ft in JulyJunipersJuniperus spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyTexas Red OakQuercus buckleyilow water, Central Valley1.07 gal/sq ft in JulyPortuguese OakQuercus faginealow water, Central Valley1.07 gal/sq ft in JulySoapbark TreeQuillaja saponarialow water, Central Valley1.07 gal/sq ft in JulyNecklace TreeSophora affinislow water, Central Valley1.07 gal/sq ft in JulyBailey AcaciaAcacia baileyanalow water, Central Valley1.07 gal/sq ft in JulySilver WattleAcacia dealbatalow water, Central Valley1.07 gal/sq ft in JulyGreen WattleAcacia decurrenslow water, Central Valley1.07 gal/sq ft in JulySydney Golden WattleAcacia longifolialow 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 flowering ash, 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 flowering ash in summer?

In July, established flowering ash in loam needs a deep watering about every 8 days in the Central Valley 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 flowering ash need per day?

In July in the Central Valley, established flowering ash needs about 6.8 gallons a day under a 10 foot canopy and about 27 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 flowering ash change across California?

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

Is flowering ash different from other ash trees?

It is a true ash, but one of the few with showy, fragrant flowers. Its white clusters open in spring with or just after the leaves. Most other ashes have flowers you would barely notice.

Can flowering ash grow near the coast?

Yes. It does well in coastal gardens with neutral to alkaline soil and full sun. It tolerates exposed or sheltered sites. Check the soil after long windy spells, which dry the ground faster.

Can you overwater flowering ash?

Yes. It wants soil that drains well, and ground that stays wet can harm the roots. Water deeply, then let the upper soil dry before the next soak. Keep lawn sprinklers from soaking the trunk area.

Does flowering ash drop messy seeds?

It produces clusters of narrow winged seeds that can hang on until late winter. They are a tidiness issue and do not reflect watering. Rake them from paving as they fall.

How big does flowering ash get?

Expect a rounded tree about 40 to 50 feet tall with smooth gray bark. Give it room in full sun, away from foundations and paving. Its root area widens with the canopy, so irrigation should widen too.

More plant watering guides

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Sources