WateringTimesWatering plan, $19
Lagerstroemia spp., hybrids & cvs., WUCOLS IV

How often to water crape myrtle in California

In July in the Central Valley, established crape myrtle in loam needs a deep watering about every 20 days: about 55 gallons each time under a 10 foot canopy, about 19 gallons a week. Crape myrtle is a deciduous shrub or small tree that flowers on new growth through summer. An established plant handles some dryness, but blooming growth still benefits from deep watering when the roots run short. Let the ground drain between soakings and keep the trunk out of soggy soil.

ShrubTreeUC Arboretum All-StarRated for 6 of 6 zones

How often to water crape myrtle, 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 crape myrtle 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

  • Dry, crumbly soil 8 to 12 inches beneath the canopy signals that an established crape myrtle needs a deep soak
  • Leaves still limp the morning after a hot afternoon can indicate thirst when the root zone is dry
  • Small flower heads can accompany dry roots, but white powder on buds or sticky leaves warrants a pest or disease check
  • Yellow leaves after summer dryness can indicate stress, while yellow, orange or red leaves can be normal fall color
  • Yellowing foliage over persistently wet soil can indicate poor drainage around crape myrtle roots

How to water it

  • Water under the canopy and beyond the branches while keeping the trunk and peeling bark dry
  • Soak soil about 12 to 18 inches deep beneath established crape myrtle, then let the upper soil dry before watering again
  • Use drip or a slow hose to send water into the root area beneath the flowering canopy
  • Spread wood-chip mulch beneath the canopy, keeping it clear of the trunk
  • Plant slightly high in heavy clay and expand emitter coverage as the canopy grows

Through the seasons

Keep a new crape myrtle root ball and the soil beside it moist through the first summer, widening coverage as roots spread. Established plants can take deeper, less frequent soakings. They leaf out late in spring, bloom on new wood in summer and lose their leaves in fall. Water matters during growth and bloom. Coastal and Central Valley rain can supply dormant plants; check desert soil through prolonged dry winter weather. WUCOLS rates crape myrtle low water on the north-central coast, in the Central Valley and on the south coast. It rates moderate water in South Inland, the high desert and the low desert.

In pots

Dwarf and semi-dwarf crape myrtles are the easiest forms to keep in containers. Check the mix two inches down often in summer, when the sunny position can dry a pot quickly. Water when that layer dries, letting excess leave the drainage holes, then empty the saucer. Give roots enough room rather than repeatedly wetting only the surface. In winter, keep the bare plant from drying completely, especially under a covered patio that blocks rain.

1 Your climate zone six WUCOLS zones, each from its own reference city
1.07gal per sq ft in JulyLow water use in the Central Valley zone
A year
6.84 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.761.52.33.00.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.761.52.33.00.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

Crape Myrtle: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.310.780.740.78
Feb0.210.260.320.870.930.93
Mar0.350.430.461.31.461.52
Apr0.470.610.561.611.891.95
May0.580.830.641.952.392.45
Jun0.640.990.692.292.852.79
Jul0.641.070.792.513.042.85
Aug0.60.950.742.332.792.6
Sep0.50.720.61.862.142.08
Oct0.350.470.461.331.461.49
Nov0.190.220.330.90.930.96
Dec0.120.140.260.680.650.68
Year4.86.846.218.4121.2721.08

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 low water in the Central Valley, like crape myrtle. Plants that drink alike can share one valve and one schedule.

LavenderLavandula spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRosemaryRosmarinus officinalislow water, Central Valley1.07 gal/sq ft in JulyBougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyOlive 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 JulyLantanaLantana camara ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria 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 JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySagebrushArtemisia spp. (shrubby)low water, Central Valley1.07 gal/sq ft in JulyWild PrivetLigustrum vulgarelow 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 crape myrtle, 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 crape myrtle in summer?

In July, established crape myrtle in loam needs a deep watering about every 20 days in the Central Valley, about every 27 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 crape myrtle need per day?

In July in the Central Valley, established crape myrtle needs about 2.7 gallons a day under a 10 foot canopy and about 11 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 crape myrtle change across California?

Yes. WUCOLS rates crape myrtle separately for each of the six California climate zones: low water in the North-Central Coastal zone, low water in the Central Valley zone, low water in the South Coastal zone, moderate water in the South Inland zone, moderate water in the High and Intermediate Desert zone, moderate water in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

How do I water crape myrtle after planting?

Feel the nursery root ball itself because it can dry faster than nearby soil. Soak both the ball and the ground immediately around it. Move water outward during the first growing season as roots extend.

Why is my crape myrtle blooming poorly?

Dryness during new growth can reduce bloom, but water is only one part of the check. Shade, heavy shearing and recent transplanting can also limit flowers. Inspect unopened buds for powdery growth or pests before increasing irrigation.

Can you overwater crape myrtle?

Yes, especially in heavy ground or a low planting spot. Wait if the deeper soil is still moist, and check drainage if growth stalls over saturated ground. Roots need air between soakings.

Does a bare crape myrtle need winter checks?

Look at spots sheltered from rain and at young plants during long dry spells. A leafless tree needs little moisture, but shelter can leave its roots dry despite storms elsewhere. Water only after checking below the surface.

How do I water crape myrtle cuttings?

Keep the rooting mix evenly moist without saturating it. Cover or mist softwood cuttings to maintain humidity around their leaves while roots form. Once rooted growth develops, allow the mix to dry slightly between waterings.

More plant watering guides

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Sources