WateringTimesWatering plan, $19
Magnolia hybrids, WUCOLS IV

How often to water hybrid magnolias in California

In July in the Central Valley, established hybrid magnolias in loam need a deep watering about every 8 days: about 55 gallons each time under a 10 foot canopy, about 47 gallons a week. Hybrid magnolias are trees and large shrubs bred from crosses such as kobus with star magnolia, or cucumber tree with Yulan. Most are deciduous and bloom in spring on bare branches, in white, pink, purple or yellow, and they range from 8 to 30 feet tall. Their fleshy roots want moist, well-drained, organically rich soil and resent disturbance.

TreeRated for 3 of 6 zones

How often to water hybrid magnolias, 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 hybrid magnolias 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 2 inches down under a young tree in summer means it is time for a slow, deep soak
  • Leaves browning at the edges in a dry spell show the tree has gone too dry, especially in light, free-draining soil
  • Browned flowers and buds after a cold night are frost damage, not a sign of thirst
  • Thin growth and poor performance in soggy ground point to too much water, since these trees need good drainage
  • Small, crusty bumps on the twigs point to scale insects, a common magnolia pest, not a water problem

How to water it

  • Water young trees regularly for their first few years, soaking the root zone 12 to 18 inches deep
  • Once established, water deeply during dry spells and let the top few inches dry between soakings
  • Plant in moist, well-drained, organically rich, slightly acidic to neutral soil, sheltered from strong wind
  • Mulch the root zone thickly with compost each spring or fall, leaving a 4 inch bare collar around the trunk
  • In a lawn, keep a bare circle at least 4 feet across around the tree so water reaches its roots

Through the seasons

Water a newly planted magnolia regularly for its first few years while its fleshy roots spread. Established trees may still need deep watering in dry spells, especially in light, free-draining soil. Flowers open on bare branches in spring, so late frost can brown them, and the leaves drop in fall. Rainy months usually keep dormant trees moist enough on the coast and in the Central Valley. WUCOLS rates hybrid magnolias moderate water on the north-central coast, in the Central Valley and on the south coast. WUCOLS has not evaluated them for South Inland, the high desert or the low desert.

In pots

Compact hybrid magnolias can grow well in large containers for years. Use a rich, slightly acidic mix and a pot with drainage holes. Pots dry out fast, so through the growing season feel the mix daily and soak it whenever the surface inch has dried, until water drains. Empty the saucer afterward. Feed during the growing season. In winter, keep the mix just moist and shelter the pot from hard frost.

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

Hybrid Magnolias: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.78–––
Feb0.530.650.81–––
Mar0.871.091.15–––
Apr1.181.521.4–––
May1.462.081.61–––
Jun1.612.481.74–––
Jul1.612.671.98–––
Aug1.492.391.86–––
Sep1.241.81.49–––
Oct0.871.181.15–––
Nov0.470.560.84–––
Dec0.310.340.65–––
Year1217.1115.5–––

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 hybrid magnolias. 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 hybrid magnolias 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 hybrid magnolias, 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 hybrid magnolias in summer?

In July, established hybrid magnolias in loam need a deep watering about every 8 days in the Central Valley and about every 11 days on the south coast. 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 do hybrid magnolias need per day?

In July in the Central Valley, established hybrid magnolias need 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 hybrid magnolias change across California?

Yes. WUCOLS rates hybrid magnolias 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, not evaluated 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 did my magnolia flowers turn brown?

Frost easily browns early buds and blooms. Choose hybrids that flower later, or plant in a spot sheltered from cold, drying winds. A warm southern exposure can push early bloom that frost then catches.

When should I prune a hybrid magnolia?

Prune as little as possible. Remove dead or damaged wood between midsummer and early fall, since cuts made in late winter or early spring bleed sap.

How long until a new magnolia blooms?

A young tree can take 3 to 4 years to bloom after planting. Smaller plants establish faster but may also wait a few years for flowers.

Are there yellow magnolias?

Yes. Yellow hybrids such as 'Butterflies' carry canary yellow, lemon-scented flowers up to 5 inches across. Each tree blooms for about a week before the leaves unfurl.

Can I move a magnolia?

It is best not to. Magnolia roots are fleshy and do not like disturbance, and hybrids such as Loebner magnolia transplant poorly. Choose the planting site carefully.

Do magnolias grow in alkaline soil?

Many prefer slightly acidic or neutral soil, but some, including Loebner magnolia, cope with alkaline or chalky soil. Where soil is very alkaline, grow a compact magnolia in a container instead.

More plant watering guides

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Sources