WateringTimesWatering plan, $19
Magnolia virginiana, WUCOLS IV

How often to water sweet bay magnolia in California

In July on the north-central coast, established sweet bay magnolia in loam needs a deep watering about every 13 days: about 55 gallons each time under a 10 foot canopy, about 29 gallons a week. Sweet bay magnolia is a slender magnolia native to the southeastern United States, grown as a 10 to 35 foot tree or a large shrub. Its glossy, dark green leaves have chalky white undersides. Fragrant, creamy-white flowers open in spring and on and off through summer. Unlike most magnolias it takes wet, boggy soil, and it wants steady moisture.

TreeRated for 2 of 6 zones

How often to water sweet bay 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 sweet bay 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

  • Leaves curling or browning at the edges in a dry spell show the roots have dried, since it prefers consistently moist soil
  • When the top 2 inches of soil feel dry in summer, it is time to water this moisture-lover
  • Pale leaves with green veins in alkaline soil point to chlorosis rather than a watering problem
  • Leaves yellowing while the mix stays waterlogged in a pot without drainage point to too much water
  • Small bumps on the stems or notched leaves point to scale or weevils, not thirst

How to water it

  • Water at the drip line with a soaker or drip, keeping the soil consistently moist
  • Soak about a foot deep, and water again before the upper soil dries out
  • Plant in acidic, organically rich soil in sun or part shade, including low, wet spots
  • Mulch with leaf litter or bark to keep the soil cool and damp
  • Use it near ponds or streams, where its love of moisture is an asset

Through the seasons

Keep a new tree evenly moist through its first summers while roots spread. Flowers open in spring and keep coming sporadically through summer until frost. Red seeds hang from cone-like fruits in fall and draw birds. In mild winters it may keep many of its leaves. On the north-central coast and the south coast, WUCOLS gives sweet bay magnolia a moderate water rating. WUCOLS has not evaluated it for the Central Valley, South Inland, the high desert or the low desert.

In pots

Dwarf forms of sweet bay magnolia suit containers near a patio, and a young tree can live in a large pot for a few years. Use an acidic, organically rich mix and a pot with drainage holes. Through summer, check the mix daily in hot spells and water before the top inch dries, since it likes steady moisture. Let excess drain, then empty the saucer. Water less in winter but keep the mix damp.

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

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

Monthly water need by climate zone

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.37–0.78–––
Feb0.53–0.81–––
Mar0.87–1.15–––
Apr1.18–1.4–––
May1.46–1.61–––
Jun1.61–1.74–––
Jul1.61–1.98–––
Aug1.49–1.86–––
Sep1.24–1.49–––
Oct0.87–1.15–––
Nov0.47–0.84–––
Dec0.31–0.65–––
Year12–15.5–––

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 not evaluated in the Central Valley, like sweet bay magnolia. Plants that drink alike can share one valve and one schedule.

Hawthorn MapleAcer crataegifoliumnot rated, Central Valleyno Central Valley ratingMountain MapleAcer glabrumnot rated, Central Valleyno Central Valley ratingMiyabe MapleAcer miyabeinot rated, Central Valleyno Central Valley ratingEverglades PalmAcoelorraphe wrightiinot rated, Central Valleyno Central Valley ratingPink CedarAcrocarpus fraxinifoliusnot rated, Central Valleyno Central Valley ratingYellowwoodAfrocarpus falcatus (Podocarpus falcatus)not rated, Central Valleyno Central Valley ratingNew Caledonian PineAraucaria columnaris (A. cookii)not rated, Central Valleyno Central Valley ratingFormosa Sugar PalmArenga englerinot rated, Central Valleyno Central Valley ratingNeemAzadirachta indicanot rated, Central Valleyno Central Valley ratingBismarck PalmBismarckia nobilisnot rated, Central Valleyno Central Valley ratingAmerican HornbeamCarpinus caroliniananot rated, Central Valleyno Central Valley ratingJapanese HornbeamCarpinus japonicanot rated, Central Valleyno Central Valley ratingAmerican YellowwoodCladrastis kentukeanot rated, Central Valleyno Central Valley ratingPagoda DogwoodCornus alternifolianot rated, Central Valleyno Central Valley ratingGiant DogwoodCornus controversanot rated, Central Valleyno Central Valley ratingButterfly PalmDypsis lutescens (Areca)not 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 sweet bay 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 much water does sweet bay magnolia need per day?

In July on the north-central coast, established sweet bay magnolia needs about 4.1 gallons a day under a 10 foot canopy and about 16 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 sweet bay magnolia change across California?

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

Can sweet bay magnolia grow in wet soil?

Yes. It tolerates wet, swampy and boggy soils, which most other magnolias cannot. It grows well near ponds and streams.

Is sweet bay magnolia evergreen?

It is deciduous to semi-evergreen, depending on the plant and the winter. Some cultivars stay evergreen through winter.

Why are my sweet bay magnolia leaves yellow?

Pale leaves with green veins usually mean chlorosis from alkaline soil. It needs acidic, organically rich soil, and more water will not fix it.

Why do sweet bay flowers close at night?

Each flower opens in the afternoon and closes at night, repeating for two or three days. Plant it near a patio to enjoy the fragrant blooms.

Why is it called beaver tree?

Early colonists used its fleshy roots as bait in beaver traps. The name stuck alongside swamp magnolia and sweetbay.

More plant watering guides

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Sources