WateringTimesWatering plan, $19
Magnolia x soulangeana, WUCOLS IV

How often to water saucer magnolia in California

In July in the Central Valley, established saucer magnolia 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. Saucer magnolia is a deciduous tree or large shrub, a lily magnolia hybrid with huge cup-shaped flowers, pinkish purple outside and white within. They open on bare branches in late winter, so late frost can spoil them. It needs consistent moisture in rich, well-drained, acidic soil, and its fleshy roots want room.

TreeRated for 4 of 6 zones

How often to water saucer magnolia, 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 saucer magnolia 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 inches down under the mulch means saucer magnolia needs a deep soak
  • Leaves browning at the edges in summer heat point to a root zone that is drying out
  • Flowers turning brown overnight in late winter are frost damage, not thirst
  • Sticky leaves and black sooty mold point to magnolia scale rather than a watering problem
  • Leaves yellowing in soil that stays soggy suggest the fleshy roots are short of air

How to water it

  • Water saucer magnolia under the canopy and beyond with a soaker, keeping the trunk dry
  • Soak 12 to 18 inches deep, then water again before the top several inches dry out completely
  • Plant in well-drained, acidic, loamy soil enriched with organic matter, away from warm southern walls
  • Mulch a wide ring and avoid digging near the trunk, since the fleshy roots need room
  • Spread irrigation outward as the canopy widens toward 15 to 25 feet

Through the seasons

Keep a new saucer magnolia evenly moist through its first summers while the fleshy roots spread. Established trees still need consistent, regular moisture, especially through summer. Flowers open in late winter before the leaves, and late frost can brown them. Leaves turn yellow-brown before falling in autumn. Rain usually covers the bare months on the coast and in the Central Valley. WUCOLS rates saucer magnolia moderate water on the north-central coast, in the Central Valley, on the south coast and in South Inland. It is marked not suited to the high desert or the low desert.

In pots

A young saucer magnolia can grow in a large container for a few years before planting out. Use a roomy pot with drainage holes and a rich, slightly acidic mix, since its fleshy roots dislike crowding. In summer heat, check 2 inches down every few days and water before the mix dries out. Empty the saucer after watering. Keep the pot sheltered from strong wind, and move it away from a warm wall in late winter.

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

Saucer Magnolia: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.78––
Feb0.530.650.810.87––
Mar0.871.091.151.3––
Apr1.181.521.41.61––
May1.462.081.611.95––
Jun1.612.481.742.29––
Jul1.612.671.982.51––
Aug1.492.391.862.33––
Sep1.241.81.491.86––
Oct0.871.181.151.33––
Nov0.470.560.840.9––
Dec0.310.340.650.68––
Year1217.1115.518.41––

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 moderate water in the Central Valley, like saucer magnolia. 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 saucer magnolia 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 saucer magnolia, 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 saucer magnolia in summer?

In July, established saucer magnolia 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 saucer magnolia need per day?

In July in the Central Valley, established saucer magnolia 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 saucer magnolia change across California?

Yes. WUCOLS rates saucer magnolia 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, not suited to this region 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 did my saucer magnolia flowers turn brown?

The flowers open in late winter and are easily damaged by frost. Avoid planting against warm southern walls, which push early bloom. Late-flowering cultivars reduce the risk.

What is the black coating on my magnolia leaves?

That is sooty mold growing on honeydew from soft magnolia scale. Control the scale and the mold fades. It is not a sign the tree needs water.

Can I plant under a saucer magnolia?

Go lightly. Its fleshy root system needs plenty of room and dislikes digging. A wide mulch ring is kinder to the roots than a bed of thirsty plants.

Is saucer magnolia related to lily magnolia?

Yes. It is a hybrid between lily magnolia and Magnolia denudata. It grows larger than lily magnolia and needs steady moisture.

Can you overwater saucer magnolia?

Yes. It needs regular moisture but also good drainage. Waterlogged soil harms the fleshy roots, so let the surface dry slightly between soakings.

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Sources