WateringTimesWatering plan, $19
Tradescantia pallida (Setcreasea pallida), WUCOLS IV

How often to water purple heart spiderwort in California

In July in the Central Valley, established purple heart spiderwort in loam needs a deep watering about every 5 days: about 1.5 gallons each time for a plant 2 feet across, about 1.9 gallons a week. Purple heart spiderwort, Tradescantia pallida, is a tender trailing perennial from Mexico with dark purple, lance-shaped leaves on sprawling stems. Small pink to pale purple flowers open in summer, each for a single day. Full sun brings the deepest purple, while shade turns the leaves greenish, and the sap can irritate skin.

PerennialRated for 6 of 6 zones

How often to water purple heart spiderwort, 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 purple heart spiderwort 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 foot 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

  • When the top inch or two of soil around the stems is dry, purple heart spiderwort is ready for water
  • Stems that flop and leaves that wrinkle in hot afternoon sun can show the root zone has dried
  • Leaves fading from purple toward green usually mean too little sun rather than a watering problem
  • Soft, collapsing stems at the base in soggy soil point to rot from poor drainage
  • Cottony clusters or crusty bumps on the stems point to mealybugs or scale, not thirst

How to water it

  • Water purple heart spiderwort at the soil beneath the trailing stems, not over the leaves
  • Moisten the soil 6 to 8 inches deep, then let the top inch dry before the next watering
  • Plant in moist, well-drained soil rich in organic matter, in full sun for the best color
  • Mulch lightly with compost between the stems to hold moisture
  • Widen the watered area as the planting spreads into new ground

Through the seasons

Water new plantings regularly until the stems start to spread. Established plants need soil checks through the warm months, when growth is fastest. Flowers open through summer, each lasting a day. Cold weather damages this tender plant, so growth and water needs drop in winter. WUCOLS rates purple heart spiderwort moderate water on the north-central coast, in the Central Valley, on the south coast and in South Inland. The rating climbs to high water in the high desert and the low desert.

In pots

Purple heart spiderwort spills nicely from hanging baskets and pots, and it is also grown as a houseplant. Use a container with drainage holes and a rich, well-drained mix. Outdoors in summer, check the mix every few days, and daily for small hanging baskets in hot sun. Water until it drains, then empty the saucer. Move pots under cover in cold weather, since the plant is frost tender.

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

Purple Heart Spiderwort: 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 purple heart spiderwort. Plants that drink alike can share one valve and one schedule.

DahliasDahlia spp.moderate water, Central Valley2.67 gal/sq ft in JulyFernsNephrolepis cordifolia (SHADE IN DESERT)moderate water, Central Valley2.67 gal/sq ft in JulyDayliliesHemerocallis spp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBegoniasBegonia & ssp. & cvs. (shade in the desert)moderate water, Central Valley2.67 gal/sq ft in JulyCalla LiliesZantedeschia aethiopica SHADE IN DESERTmoderate water, Central Valley2.67 gal/sq ft in JulySageSalvia officinalis and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBicolor MonkshoodAconitum cammarummoderate water, Central Valley2.67 gal/sq ft in JulyGarden MonkshoodAconitum napellusmoderate water, Central Valley2.67 gal/sq ft in JulyCarpet BugleAjuga reptans (shade)moderate water, Central Valley2.67 gal/sq ft in JulySnowdrop WindflowerAnemone sylvestrismoderate water, Central Valley2.67 gal/sq ft in JulyMountain SandwortArenaria montanamoderate water, Central Valley2.67 gal/sq ft in JulySwamp MilkweedAsclepias incarnatamoderate water, Central Valley2.67 gal/sq ft in JulyOrange MilkweedAsclepias tuberosamoderate water, Central Valley2.67 gal/sq ft in JulyGreater MasterwortAstrantia majormoderate water, Central Valley2.67 gal/sq ft in JulyHardy BegoniaBegonia grandismoderate water, Central Valley2.67 gal/sq ft in JulyWax BegoniaBegonia semperflorensmoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

Rated lower than purple heart spiderwort in the Central Valley. Worth a look for a new bed or a lawn replacement.

AgapanthusAgapanthus orientalislow water, Central Valley1.07 gal/sq ft in JulyGeraniumsPelargonium x hortorum and cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyIrisesIris germanicalow water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyYarrowAchillea millefolium (non-native hybrids)low water, Central Valley1.07 gal/sq ft in JulyMountain AlyssumAlyssum montanumlow water, Central Valley1.07 gal/sq ft in JulySilver SageSalvia argentealow water, Central Valley1.07 gal/sq ft in JulyPurple MulleinVerbascum phoeniceumlow water, Central Valley1.07 gal/sq ft in JulySilvery YarrowAchillea clavennaelow water, Central Valley1.07 gal/sq ft in JulyFern Leaf YarrowAchillea filipendulinalow water, Central Valley1.07 gal/sq ft in JulyCalifornia Native YarrowAchillea millefolium (CA native cultivars)low water, Central Valley1.07 gal/sq ft in JulyWoolly YarrowAchillea tomentosalow water, Central Valley1.07 gal/sq ft in JulyPerennial HollyhockAlcea rosea cvs.low water, Central Valley1.07 gal/sq ft in JulyMountain Lady's MantleAlchemilla alpinalow 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 purple heart spiderwort, 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 purple heart spiderwort in summer?

In July, established purple heart spiderwort in loam needs a deep watering about every 5 days in the Central Valley, about every 7 days on the south coast and about every 6 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 purple heart spiderwort need per day?

In July in the Central Valley, established purple heart spiderwort 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 purple heart spiderwort change across California?

Yes. WUCOLS rates purple heart spiderwort 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 did my purple heart turn green?

Shade makes the leaves greenish, while full sun keeps them deep purple. Move it to a sunnier spot rather than changing how you water.

Is purple heart spiderwort toxic?

Eating it can irritate the mouth and stomach, and the sap from leaves and stems can irritate skin in people and pets. Wear gloves when trimming it.

How do I propagate purple heart spiderwort?

Stem cuttings are the best way. Keep cuttings in lightly moist mix until roots form, then water them like established plants.

Will purple heart spread in my garden?

It tends to spread and can become invasive in beds. Trim the edges and pull stray stems to keep it in bounds.

Can you overwater purple heart spiderwort?

Yes. It wants moist but well-drained soil, and soggy ground can rot the stems. Let the surface dry between waterings.

More plant watering guides

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Sources