WateringTimesWatering plan, $19
Hoya carnosa, WUCOLS IV

How often to water wax plant in California

In July on the north-central coast, established wax plant in loam needs a deep watering about every 13 days: about 2.2 gallons each time for a plant 2 feet across, about 1.1 gallons a week. Wax plant is an evergreen climbing vine with thick, waxy, succulent leaves, often flecked with silver or cream. Mature plants bear round clusters of up to 30 star-shaped flowers, shiny white to pink. It grows naturally perched on trees, so it wants a loose, fast-draining mix that dries between waterings. Leaves drop when it is kept too wet or too dry.

VineRated for 3 of 6 zones

How often to water wax plant, 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 wax plant 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

  • Mix or soil dry about an inch down signals that wax plant is ready for water, since its thick leaves store moisture
  • Leaves turning soft or slightly wrinkled can show the plant has dried too far
  • Leaves dropping can follow either soggy or bone-dry soil, so check the root zone before changing anything
  • Tiny flies around a pot point to fungus gnats, a sign the mix is staying too wet
  • Cottony white clusters in the leaf joints point to mealybugs rather than a watering fault

How to water it

  • Water at the base until the soil or mix is evenly moist, using room temperature water rather than cold
  • Let the top inch or so dry out before watering again
  • Plant outdoors only in loose, fast-draining soil rich in organic matter, in bright light with shade from hot sun
  • Give the vine a support to climb, and leave old flower spurs in place since they bloom again
  • Mulch lightly around in-ground plants to steady moisture between soakings

Through the seasons

Keep a new planting barely moist while roots grow into the mix. Established plants take a thorough watering once the top of the soil dries, through spring, summer and fall, when flowers can appear. Most plants will not bloom until they are 2 or 3 years old. Water less in winter, and protect the plant from chilly nights. WUCOLS rates wax plant moderate water on the north-central coast, on the south coast and in South Inland. WUCOLS marks it as not suited to the Central Valley, the high desert or the low desert.

In pots

Wax plant is usually grown in a pot or hanging basket, and it does not mind being pot-bound. Use a loose, fast-draining mix high in organic matter and a container with good drainage. Water when the top of the mix has dried, soaking until water runs out, then empty the saucer. A summer outdoors in partial shade suits it, but bring it in once nights fall below 50 degrees F. In winter, water less often while growth is slow.

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

WUCOLS lists Wax Plant as not suited to this region for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Wax Plant: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.37–0.780.78––
Feb0.53–0.810.87––
Mar0.87–1.151.3––
Apr1.18–1.41.61––
May1.46–1.611.95––
Jun1.61–1.742.29––
Jul1.61–1.982.51––
Aug1.49–1.862.33––
Sep1.24–1.491.86––
Oct0.87–1.151.33––
Nov0.47–0.840.9––
Dec0.31–0.650.68––
Year12–15.518.41––

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 10

Rated not suited to this region in the Central Valley, like wax plant. Plants that drink alike can share one valve and one schedule.

Golden Trumpet VineAllamanda catharticanot rated, Central Valleyno Central Valley ratingPelican FlowerAristolochia giganteanot rated, Central Valleyno Central Valley ratingFlame VinePyrostegia venustanot rated, Central Valleyno Central Valley ratingCup-of-Gold VineSolandra maximanot rated, Central Valleyno Central Valley ratingMadagascar JasmineStephanotis floribundanot rated, Central Valleyno Central Valley ratingBlack-Eyed Susan VineThunbergia alatanot rated, Central Valleyno Central Valley ratingSky Flower VineThunbergia grandifloranot rated, Central Valleyno Central Valley ratingCoral VineAntigonon leptopusnot rated, Central Valleyno Central Valley ratingQueen's WreathPetrea volubilisnot rated, Central Valleyno Central Valley ratingBeauverd's Widow's-ThrillKalanchoe beauverdiinot 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 wax plant, 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 wax plant in summer?

In July, established wax plant in loam needs a deep watering 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 wax plant need per day?

In July on the north-central coast, established wax plant needs about 0.2 gallons a day for a plant 2 feet across and about 0.7 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 wax plant change across California?

Yes. WUCOLS rates wax plant separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, not suited to this region in the Central Valley zone, moderate water in the South Coastal zone, moderate water in the South Inland zone, not suited to this region in the High and Intermediate Desert zone, not suited to this region in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Why isn't my wax plant blooming?

Most plants need to be 2 or 3 years old before they flower. Cutting off the old flower spurs also removes future blooms, since the same spurs flower again for years. Give it bright, indirect light.

Why are my wax plant leaves falling off?

Soil that is too wet or too dry can cause leaf drop. Check the mix before watering, and let the top dry between waterings. Cold water can also shock the plant, so use water at room temperature.

Does wax plant like humidity?

Yes. It thrives in high humidity, and dry air can bring on spider mites. Indoors, group pots together or set the pot on a tray of wet pebbles.

Should I repot my wax plant?

Only when it outgrows its pot, since it does not mind being crowded. Move up no more than 2 inches at a time, and avoid repotting while it is in bud or flower.

Can you overwater wax plant?

Yes. It grows perched on trees in nature and needs a loose, fast-draining mix. Soggy soil causes leaf drop and draws fungus gnats, so let the top of the mix dry between waterings.

More plant watering guides

Wandering JewMoses-in-the-CradleWhite CloverCanadian HemlockCardboard PalmCoral VineHeath-Leafed BanksiaTree Banksia

Sources