WateringTimesWatering plan, $19
Nyssa sylvatica, WUCOLS IV

How often to water sour gum in California

In July in the Central Valley, established sour gum 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. Sour gum, also called black tupelo, is a native eastern American deciduous tree grown for its glossy, dark green summer leaves and brilliant scarlet fall color. It grows slowly, about 12 to 15 feet in ten years, eventually reaching 40 to 70 feet. It prefers moist, acidic soil in full sun and even tolerates poorly drained ground and standing water.

TreeRated for 4 of 6 zones

How often to water sour gum, 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 sour gum 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 a foot down under the canopy of a young sour gum in summer means it is due for a long soak
  • Shiny leaves drooping and losing their gloss in a heat wave can indicate a dry root zone
  • Leaves coloring and dropping in midsummer, weeks early, can follow drought stress
  • Yellowing leaves and thin growth where water never drains away point to soggy, airless soil

How to water it

  • Lay soakers across the root zone under the crown and a little beyond it
  • Soak young trees about 18 inches deep, and water again once the upper few inches dry
  • Plant in full sun in moist, acidic soil, including spots that stay damp
  • Mulch broadly to keep the soil cool and evenly moist
  • Expect slow growth, and widen the watered area gradually

Through the seasons

Water a young sour gum deeply and often through its first summers, since its natural habitats are often moist. Established trees tolerate some drought and dry soil, but steady moisture keeps growth moving. It is deciduous, with scarlet fall color, and rests bare in winter when rain covers its needs in most regions. WUCOLS rates sour gum moderate water on the north-central coast, in the Central Valley and on the south coast. South Inland raises it to a high water rating. WUCOLS marks it as not suited to the high desert or the low desert.

In pots

Sour gum grows slowly enough that a young tree can live a few years in a large, deep container. Use a moist, acidic, well-drained mix. When the top inch or two feels dry, water slowly until it drains out below. Through summer heat, check every day or two. Pour off the saucer. After the leaves color and drop, water lightly until spring, then plant it out while it is still small.

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
1.02.03.04.00.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC1.02.03.04.00.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Sour Gum: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.781.24––
Feb0.530.650.811.39––
Mar0.871.091.152.08––
Apr1.181.521.42.58––
May1.462.081.613.12––
Jun1.612.481.743.67––
Jul1.612.671.984.02––
Aug1.492.391.863.72––
Sep1.241.81.492.98––
Oct0.871.181.152.13––
Nov0.470.560.841.44––
Dec0.310.340.651.09––
Year1217.1115.529.46––

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 sour gum. 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 sour gum 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 sour gum, 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 sour gum in summer?

In July, established sour gum 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 5 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 sour gum need per day?

In July in the Central Valley, established sour gum 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 sour gum change across California?

Yes. WUCOLS rates sour gum 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, high 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 is sour gum known for fall color?

Its leaves turn brilliant scarlet red in autumn, among the best fall colors of any tree. Summer leaves are shiny and dark green.

How fast does sour gum grow?

Growth is slow at first, roughly a foot or so a year for its first decade. Regular water helps it grow faster. Mature trees reach 40 to 70 feet.

Can sour gum grow in wet soil?

Yes, it tolerates poorly drained soil and even standing water. It also handles some drought. That makes it useful in low spots.

Does sour gum need acid soil?

It prefers moist, acidic soil. Amend with organic matter and mulch. Keep the root zone cool and moist.

Is sour gum native?

It is native to eastern and central North America, not California. It grows wild from dry ridges to swamp margins. It adapts well to gardens.

More plant watering guides

Arizona White OakIndian HempPersian CyclamenTotaraSpider PlantYaupon HollyRed Hot PokerSunshine Chinese Privet

Sources