WateringTimesWatering plan, $19
Fraxinus angustifolia 'Raywood' (F. oxycarpa), WUCOLS IV

How often to water Raywood ash in California

In July in the Central Valley, established Raywood 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. Raywood ash is a fast-growing deciduous shade tree, usually 40 to 50 feet tall, with an oval crown. Its finely divided leaves turn purplish red in fall, earning it the name claret ash. It rarely sets seed, so it drops little fruit. It is less drought tolerant than once believed, and dry soil leaves it open to a canker that kills limbs.

TreeRated for 5 of 6 zones

How often to water Raywood 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 Raywood 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

  • Scattered limbs whose leaves yellow, wilt and then brown point to Raywood ash canker, which follows drought stress
  • Reddish brown cankers and cracking bark on dying limbs confirm the canker, and deep summer watering helps prevent more
  • Soil dry a foot down under the canopy in midsummer means the tree needs a slow, deep soak
  • Yellowing leaves across the whole crown over soggy ground point to poor drainage rather than drought
  • Small holes and sawdust on the trunk of a young tree point to ash or lilac borer, a serious pest

How to water it

  • Give occasional deep soakings through the dry season, wetting the soil 18 inches down or more
  • Water broadly under and beyond the canopy, since the roots run near the surface
  • Plant in full sun in well-drained soil, away from paving that surface roots can lift
  • Thin the canopy with careful pruning to cut its water demand and lighten limbs that break easily
  • Stake a new tree and water it carefully, since it can be hard to establish and may topple

Through the seasons

Water a new tree regularly through its first few summers, since it can be hard to establish. Established trees still need occasional deep soakings through the dry season, because drought stress invites the canker that kills limbs. Leaves turn purplish red in fall, then drop. Winter rain usually covers the bare tree on the coast and in the Central Valley. WUCOLS rates Raywood ash moderate water on the north-central coast, in the Central Valley and on the south coast. South Inland and the high desert share that moderate water rating. WUCOLS marks it as not suited to the low desert.

In pots

Raywood ash grows into a 40 to 50 foot tree, so it belongs in a container only briefly as a young nursery tree. Keep it in a deep pot with drainage holes and a well-drained mix, in full sun. On hot days, probe the mix 2 inches down and water once it is dry there. Let the water run out the bottom, then empty the saucer. Plant it in the ground before its roots circle the pot.

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
0.761.52.33.00.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.761.52.33.00.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.780.74–
Feb0.530.650.810.870.93–
Mar0.871.091.151.31.46–
Apr1.181.521.41.611.89–
May1.462.081.611.952.39–
Jun1.612.481.742.292.85–
Jul1.612.671.982.513.04–
Aug1.492.391.862.332.79–
Sep1.241.81.491.862.14–
Oct0.871.181.151.331.46–
Nov0.470.560.840.90.93–
Dec0.310.340.650.680.65–
Year1217.1115.518.4121.27–

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 Raywood 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 Raywood 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 Raywood 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 Raywood ash in summer?

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

In July in the Central Valley, established Raywood 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 Raywood ash change across California?

Yes. WUCOLS rates Raywood 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, moderate water in the South Coastal zone, moderate water in the South Inland zone, moderate water in the High and Intermediate Desert zone, not suited to this region in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Why are branches dying on my Raywood ash?

Raywood ash commonly suffers canker and decline, caused by a weak fungus that kills limbs on drought-stressed trees. Whole trees are rarely killed, but dead limbs can break and fall. Remove them, and give occasional deep summer watering.

Is Raywood ash drought tolerant?

Less than was once believed. Moisture stress opens it to the canker that kills limbs. Plan on deep soakings through the dry season, even for established trees.

Does Raywood ash make a mess?

It is reported to produce mostly male flowers, so it sets little or no fruit. Some trees do produce fruit. Fall leaf drop is the main cleanup.

Why are my Raywood ash roots coming up?

It has aggressive surface roots that can lift paving and crowd lawns. Plant it well away from walks and foundations, and mulch the root zone instead of growing turf there.

What can I plant instead of Raywood ash?

Green ash looks similar and appears not to suffer from Raywood ash canker and decline. Check that it suits your site before planting.

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Sources