WateringTimesWatering plan, $19
Platanus x hispanica and cvs. (Platanus x acerfolia), WUCOLS IV

How often to water London plane in California

In July in the Central Valley, established London plane 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. London plane is a fast-growing, deciduous hybrid of American sycamore and Oriental plane, with flaking bark that shows cream and olive patches. It prefers deep, moist, well drained soil and copes with clay and city conditions. Its big leaves draw steadily on summer soil moisture, and its water need climbs in both desert zones.

TreeRated for 6 of 6 zones

How often to water London plane, 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 London plane 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

  • A young London plane is ready for water when soil at the canopy edge is dry 4 to 6 inches down
  • Broad leaves that scorch brown at the margins during summer heat can mean the roots are running short
  • Brown blotches along the leaf veins and dying shoot tips after a wet spring point to anthracnose, not thirst
  • A white powdery film on new summer leaves is powdery mildew, so judge soil moisture separately
  • Wilting that does not recover after watering, with soggy soil at the trunk base, warrants a check for root rot

How to water it

  • Water a young London plane over its root ball and the soil just beyond, widening the wet circle each year
  • Run water slowly until the soil is moist about 18 inches deep, then let the upper few inches dry
  • Use drip, bubblers or a soaker ring at ground level, since spray on the leaves spreads anthracnose
  • Move emitters out under the canopy edge of an older tree and keep the trunk itself dry
  • Keep a wide layer of wood chip mulch over the root area, and clear fallen fruit balls and twigs off the drip lines

Through the seasons

Water a new London plane deeply through its first few summers, widening coverage as the roots spread. Established trees still want deep summer soakings, since this tree prefers moist soil. Leaves open in spring, when wet weather can bring anthracnose, and drop in fall, while the fruit balls hang on through winter. Winter rain covers the cool months on the coast and in the Central Valley. WUCOLS rates London plane moderate water on the north-central coast, in the Central Valley, on the south coast and in South Inland. It rates high water in the high desert and the low desert, where dry winter spells also call for soil checks.

In pots

A London plane grows too fast to stay in a container for long, so treat a pot as a holding stage before planting. Check a nursery can 2 to 3 inches down every few days in summer, and every day in desert heat. Water until it flows from the drainage holes, then empty the saucer. Its broad leaves lose water quickly on hot, windy afternoons, so a potted tree can wilt fast. Once the leaves drop in fall, water the bare tree only when the mix is dry below the surface.

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
1.22.43.64.90.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC1.22.43.64.90.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

London Plane: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.781.191.24
Feb0.530.650.810.871.491.49
Mar0.871.091.151.32.332.43
Apr1.181.521.41.613.033.12
May1.462.081.611.953.823.92
Jun1.612.481.742.294.564.46
Jul1.612.671.982.514.864.56
Aug1.492.391.862.334.464.17
Sep1.241.81.491.863.423.32
Oct0.871.181.151.332.332.38
Nov0.470.560.840.91.491.54
Dec0.310.340.650.681.041.09
Year1217.1115.518.4134.0333.73

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 London plane. 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 London plane 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 London plane, 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 London plane in summer?

In July, established London plane 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 London plane need per day?

In July in the Central Valley, established London plane 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 London plane change across California?

Yes. WUCOLS rates London plane 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, high water in the High and Intermediate Desert zone, high water 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 my London plane losing leaves in spring?

A wet spring often brings anthracnose, which browns leaves along the veins and can kill new shoots. The disease fades in hot, dry weather and rarely does lasting harm in California. Keep sprinklers off the foliage rather than adding water.

Which London plane variety should I plant?

'Bloodgood' resists anthracnose but not powdery mildew. 'Yarwood' resists powdery mildew but is prone to anthracnose. Pick by the disease that troubles trees where you live, and water either one at soil level.

Will London plane roots lift my sidewalk?

They can, and they are known to enter sewer pipes as well. Plant it where it has plenty of open ground. Deep soakings under the canopy draw roots downward, while light, frequent watering keeps them near the surface.

Can a London plane grow in a lawn?

It tolerates the moist soil of a lawn, but sprinkler spray on low leaves can spread anthracnose in spring. Aim lawn heads away from the canopy. Give the tree its own deep soak under the outer branches in summer.

Is London plane a messy tree?

Yes. Twigs, big leaves, bark flakes and bristly fruit balls fall through the year. Clear litter from emitters and drip lines so water keeps reaching the roots.

Should I pollard my London plane?

Pollarding removes infected shoots and can help control anthracnose. It also forces masses of tender new growth, which powdery mildew favors. If you plan to pollard every year, 'Yarwood' is a sound choice because it resists mildew.

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Sources