WateringTimesWatering plan, $19
Clematis viticella, WUCOLS IV

How often to water Italian clematis in California

In July in the Central Valley, established Italian clematis in loam needs a deep watering about every 8 days: about 2.2 gallons each time for a plant 2 feet across, about 1.9 gallons a week. Italian clematis is a fast-growing vine from southern Europe that twines 10 to 15 feet, sometimes more. From midsummer into fall it bears bell-shaped flowers in blue-violet or deep purple, followed by small fruits with silky, feathery tails. It is highly resistant to clematis wilt. All parts are highly poisonous.

VineRated for 3 of 6 zones

How often to water Italian clematis, month by month

Your city
Plant width
2 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 Italian clematis 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 3 inches down at the base in summer means Italian clematis needs a deep drink
  • Shoot tips wilting in afternoon sun point to a dry root zone
  • Flowers fading early in a hot spell can follow dry soil
  • White powder on leaves points to powdery mildew, not water

How to water it

  • Water the base deeply, then let the top couple of inches dry
  • Keep the roots shaded with mulch, stones or low plants
  • Plant with the vine in sun and roots in shade, in humus-rich, well-drained soil
  • Cut it back to about a foot tall in late winter or early spring
  • Give it a fence, arbor or shrub to climb

Through the seasons

Water new vines regularly through the first summer. Established plants need deep watering in dry spells and cool, shaded roots. It blooms on new growth from summer into fall, so a hard cutback in late winter or early spring brings the best flowers. WUCOLS rates Italian clematis low water on the north-central coast. In the Central Valley and South Inland it carries a moderate water rating. WUCOLS has not evaluated it for the south coast, the high desert or the low desert.

In pots

Italian clematis can grow in a large pot with a trellis, or spill over the rim of a tall container. Use a humus-rich, well-drained mix. Water when the top inch or two is dry, until it drains. In summer, check every day or two and shade the pot itself so the roots stay cool. Empty the saucer. Cut it back hard in late winter. In winter, water lightly.

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
0.671.32.02.70.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.671.32.02.70.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Italian Clematis: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.4–0.78––
Feb0.210.65–0.87––
Mar0.351.09–1.3––
Apr0.471.52–1.61––
May0.582.08–1.95––
Jun0.642.48–2.29––
Jul0.642.67–2.51––
Aug0.62.39–2.33––
Sep0.51.8–1.86––
Oct0.351.18–1.33––
Nov0.190.56–0.9––
Dec0.120.34–0.68––
Year4.817.11–18.41––

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 Italian clematis. Plants that drink alike can share one valve and one schedule.

JasmineJasminum polyanthummoderate water, Central Valley2.67 gal/sq ft in JulyStar JasmineTrachelospermum jasminoides and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyHoneysuckleLonicera japonicamoderate water, Central Valley2.67 gal/sq ft in JulyIvyHedera helixmoderate water, Central Valley2.67 gal/sq ft in JulyGrapevinesVitis vinifera ssp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyClematisClematis & ssp., hybrids & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyEvergreen ClematisClematis armandiimoderate water, Central Valley2.67 gal/sq ft in JulyWinter CreeperEuonymus fortunei radicansmoderate water, Central Valley2.67 gal/sq ft in JulyArabian JasmineJasminum sambacmoderate water, Central Valley2.67 gal/sq ft in JulyHyacinth BeanLablab purpureus (Dolichos lablab)moderate water, Central Valley2.67 gal/sq ft in JulyTrumpet HoneysuckleLonicera sempervirensmoderate water, Central Valley2.67 gal/sq ft in JulyPink Trumpet VinePodranea ricasolianamoderate water, Central Valley2.67 gal/sq ft in JulyPotato VineSolanum laxum (jasminoides)moderate water, Central Valley2.67 gal/sq ft in JulyHopsHumulus lupulusmoderate water, Central Valley2.67 gal/sq ft in JulyBoston IvyParthenocissus tricuspidatamoderate water, Central Valley2.67 gal/sq ft in JulyVirginia CreeperParthenocissus quinquefolia ssp. & cvs.moderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 9

Rated lower than Italian clematis in the Central Valley. Worth a look for a new bed or a lawn replacement.

BougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyWisteriaWisteria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyFlowering WoodbineLonicera periclymenumlow water, Central Valley1.07 gal/sq ft in JulyFleeceflowerFallopia baldschuanica (Polygonum aubertii)low water, Central Valley1.07 gal/sq ft in JulyCarolina JessamineGelsemium sempervirenslow water, Central Valley1.07 gal/sq ft in JulyCecile Brunner RoseRosa 'Cecile Brunner'low water, Central Valley1.07 gal/sq ft in JulyLady Banks RoseRosa banksiaelow water, Central Valley1.07 gal/sq ft in JulyRoger's Red GrapeVitis 'Roger's Red'low water, Central Valley1.07 gal/sq ft in JulyBlue Dawn Morning GloryIpomoea acuminatalow 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 Italian clematis, 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 Italian clematis in summer?

In July, established Italian clematis in loam needs a deep watering about every 8 days in the Central Valley 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 Italian clematis need per day?

In July in the Central Valley, established Italian clematis needs about 0.3 gallons a day for a plant 2 feet across and about 1.1 gallons a day for a plant 4 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 Italian clematis change across California?

Yes. WUCOLS rates Italian clematis separately for each of the six California climate zones: low water in the North-Central Coastal zone, moderate water in the Central Valley zone, not evaluated in the South Coastal zone, moderate water 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.

When should I prune Italian clematis?

Cut it back to about 1 foot tall in late winter or early spring. It blooms on new wood. Water as new shoots grow.

Does Italian clematis get clematis wilt?

It is highly resistant to clematis wilt. Powdery mildew can still appear. Aphids may attack young growth.

Can Italian clematis grow in shade?

It grows in part shade or full sun with the roots shaded. Shaded roots matter most. Mulch helps.

Is Italian clematis poisonous?

Yes, it has high severity poison characteristics. Keep children and pets from chewing it. Wear gloves when pruning.

What soil does Italian clematis like?

Moist, well-drained soil with neutral to alkaline pH suits it. Add humus at planting. Avoid soggy ground.

More plant watering guides

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Sources