WateringTimesWatering plan, $19
Vitex negundo 'Heterophylla', WUCOLS IV

How often to water cut-leaf chaste tree in California

In July on the north-central coast, established cut-leaf chaste tree in loam needs a deep watering about every 13 days: about 8.8 gallons each time for a plant 4 feet across, about 4.6 gallons a week. Cut-leaf chaste tree is a fast-growing deciduous shrub or small tree with deeply lobed, lacy leaflets. Violet-blue flower spikes open on new wood in late summer, and it does best with heat and full sun. Soak it deeply in loam or sandy soil that drains well, then let the upper soil dry, since stressed plants can get root rot.

ShrubRated for 2 of 6 zones

How often to water cut-leaf chaste tree, month by month

Your city
Plant width
4 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 cut-leaf chaste tree 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 the plant covers, 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 plant width

A shrub with its width marked from one side to the other and the circle under it shaded blue

Measure across the plant, from the tips of the leaves on one side to the tips on the other.

Water the whole area the plant covers, shown in blue. The gallons here cover that area.

A wider plant means more gallons each watering, not more waterings. While it is young, measure again each spring.

How to tell it needs water

  • Soil dry 4 to 6 inches down under the outer branches signals that cut-leaf chaste tree needs a deep soak
  • Lacy leaflets that still hang limp in the morning over dry ground can indicate thirst
  • Flower spikes that stall or brown early in late summer can accompany a dry root zone during bloom
  • Yellowing leaves and weak new shoots over soil that stays wet can point to root rot
  • Afternoon droop on a hot day that is gone by evening does not by itself call for water

How to water it

  • Water cut-leaf chaste tree under its canopy with drip or a slow hose, keeping the stem bases out of standing water
  • Soak the root zone 12 to 18 inches deep, then let the top few inches dry before the next soak
  • Plant it in loam or sandy soil that drains well, using a low mound where clay holds water
  • Spread coarse mulch across the root area and leave a few inches bare around the stems
  • Move emitters outward as the vase-shaped crown widens over the seasons

Through the seasons

Keep a new cut-leaf chaste tree evenly moist through its first summer, widening the soaked area as roots spread. Established plants take deeper soakings with longer dry spells between them. Leaves fall in autumn, and the bare plant needs little water until spring. New shoots grow quickly from late spring and carry the flowers in late summer, so check the soil most closely from leaf out through bloom. On the north-central coast, winter rain usually covers the leafless months. In the low desert, check the soil during dry winter spells. WUCOLS rates cut-leaf chaste tree moderate water on the north-central coast and in the low desert. WUCOLS has not evaluated it for the Central Valley, the south coast, South Inland or the high desert.

In pots

Cut-leaf chaste tree grows fast, so a container suits a young plant or one kept small by hard pruning in early spring. Choose a large pot with open drainage holes and a gritty, loamy mix. In summer heat, check the mix 2 inches down every few days, and daily on a sunny patio. Water until it runs out the bottom, then empty the saucer. After leaf drop, water only when the mix is dry well below the surface. Move the pot to shelter before a hard freeze, since potted roots are more exposed than roots in the ground.

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

WUCOLS lists Cut-Leaf Chaste Tree as not evaluated for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Cut-Leaf Chaste Tree: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.37––––0.78
Feb0.53––––0.93
Mar0.87––––1.52
Apr1.18––––1.95
May1.46––––2.45
Jun1.61––––2.79
Jul1.61––––2.85
Aug1.49––––2.6
Sep1.24––––2.08
Oct0.87––––1.49
Nov0.47––––0.96
Dec0.31––––0.68
Year12––––21.08

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 not evaluated in the Central Valley, like cut-leaf chaste tree. Plants that drink alike can share one valve and one schedule.

Formosa Sugar PalmArenga englerinot rated, Central Valleyno Central Valley ratingChilean Feather BambooChusquea culeou (C. breviglumis)not rated, Central Valleyno Central Valley ratingBlackbrushColeogyne ramosissimanot rated, Central Valleyno Central Valley ratingGlaucous Scorpion VetchCoronilla valentina glaucanot rated, Central Valleyno Central Valley ratingWillowleaf CotoneasterCotoneaster salicifoliusnot rated, Central Valleyno Central Valley ratingMadagascar SagoCycas thouarsii (SHADE)not rated, Central Valleyno Central Valley ratingIrish HeathDaboecia cantabricanot rated, Central Valleyno Central Valley ratingButterfly PalmDypsis lutescens (Areca)not rated, Central Valleyno Central Valley ratingUmbrella BambooFargesia murielaenot rated, Central Valleyno Central Valley ratingBlue Fountain BambooFargesia nitida (Sinarundinaria nitida) (BAMBOO)not rated, Central Valleyno Central Valley ratingPrickly HeathGaultheria mucronata (Pernettya mucronata)not rated, Central Valleyno Central Valley ratingOtterbossieGossypium harknessiinot rated, Central Valleyno Central Valley ratingBox-leaved HollyIlex crenatanot rated, Central Valleyno Central Valley ratingBellyache BushJatropha gossypiifolianot rated, Central Valleyno Central Valley ratingMountain LaurelKalmia latifolianot rated, Central Valleyno Central Valley ratingBarbados CherryMalpighia glabranot 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 cut-leaf chaste tree, 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 cut-leaf chaste tree need per day?

In July on the north-central coast, established cut-leaf chaste tree needs about 0.7 gallons a day for a plant 4 feet across and about 2.6 gallons a day for a plant 8 feet across. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for cut-leaf chaste tree change across California?

Yes. WUCOLS rates cut-leaf chaste tree separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, not evaluated in the Central Valley zone, not evaluated in the South Coastal zone, not evaluated in the South Inland zone, not evaluated 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.

Should I cut back cut-leaf chaste tree in spring?

You can. It flowers on new wood, so a hard cut in early spring still leaves time for late summer bloom. A flush of fast shoots follows, so check the soil as they leaf out.

Why is my cut-leaf chaste tree not flowering?

It needs a warm growing season and full sun to ripen its wood and set flowers. A shaded spot or a cool summer can leave it leafy with few spikes. Extra water does not make up for low light or cool weather.

Does cut-leaf chaste tree attract bees?

Yes. Its violet-blue spikes draw bees and butterflies in late summer. Water at the base with drip during bloom rather than spraying the flowers while insects are working them.

Is cut-leaf chaste tree a shrub or a tree?

It can be either. Left alone it grows into a small tree with an open, vase shape, while hard pruning keeps it shrub sized. Spread water to the edge of whatever crown you keep.

Can you overwater cut-leaf chaste tree?

Yes. It wants loam or sandy soil with good drainage, and root rot can strike stressed plants. Let the top few inches dry between soakings and fix soggy ground before watering again.

Does cut-leaf chaste tree lose its leaves in winter?

Yes. It is deciduous, so it stands bare from autumn until spring growth begins. Water use drops sharply while it is leafless, so feel the soil before soaking a dormant plant.

More plant watering guides

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Sources