WateringTimesWatering plan, $19
Catharanthus roseus, WUCOLS IV

How often to water Madagascar periwinkle in California

In July in the Central Valley, established Madagascar periwinkle 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. Madagascar periwinkle is a warm-season flowering plant with glossy leaves and five-petaled blooms in shades of pink, white and red. It thrives in heat and needs the soil to dry somewhat between waterings. Root and stem diseases can affect it, so choose a site that drains freely and avoid overwatering.

PerennialRated for 5 of 6 zones

How often to water Madagascar periwinkle, 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 Madagascar periwinkle 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

  • Dry soil around a flowering periwinkle calls for checking moisture beneath the surface
  • Wilting that persists after the afternoon heat calls for a soil check before more water
  • A drop in flowering calls for checking growing conditions, rather than automatically increasing irrigation
  • Wet soil that lingers around the stem base suggests overwatering or inadequate drainage
  • Sudden wilting over soil that is still damp warrants a check for root rot rather than more water

How to water it

  • Water at the base of the plant, soaking the top several inches of soil around the roots
  • Let the surface dry before watering a bed of Madagascar periwinkle again
  • Use drip or a watering can rather than overhead sprinklers that wet the foliage
  • Plant in fast-draining soil, raising the bed where clay keeps the ground soggy
  • Space new transplants to allow airflow as the bed fills in and spreads

Through the seasons

In its first year, Madagascar periwinkle needs steady moisture while young roots establish, with some drying between waterings. Established plants grow and flower through the warm months from late spring into fall, needing less water as temperatures cool. It can remain evergreen in frost-free conditions, but cold weather limits its use elsewhere. Use it as summer bedding where winter frost occurs. Coastal and inland rain in the cool season can keep soil wetter than this plant prefers. WUCOLS rates Madagascar periwinkle moderate water on the north-central coast, in the Central Valley and on the south coast. It also rates moderate water in South Inland and the high desert. WUCOLS marks it as not suited to the low desert.

In pots

Madagascar periwinkle grows well in a container with fast-draining mix and open holes at the base. Feel the top inch during warm California weather and water once it has dried there. Water slowly until it flows from the drainage holes, then tip out the saucer right away, since sitting water invites root rot. Ease back on watering during cool, overcast stretches, when the mix stays damp far longer than it does in summer heat. Protect this tender perennial from frost in winter, or grow it as seasonal bedding.

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
0.761.52.33.00.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.761.52.33.00.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Madagascar Periwinkle: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.780.74–
Feb0.530.650.810.870.93–
Mar0.871.091.151.31.46–
Apr1.181.521.41.611.89–
May1.462.081.611.952.39–
Jun1.612.481.742.292.85–
Jul1.612.671.982.513.04–
Aug1.492.391.862.332.79–
Sep1.241.81.491.862.14–
Oct0.871.181.151.331.46–
Nov0.470.560.840.90.93–
Dec0.310.340.650.680.65–
Year1217.1115.518.4121.27–

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 Madagascar periwinkle. 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 Madagascar periwinkle 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 Madagascar periwinkle, 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 Madagascar periwinkle in summer?

In July, established Madagascar periwinkle 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 Madagascar periwinkle need per day?

In July in the Central Valley, established Madagascar periwinkle 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 Madagascar periwinkle change across California?

Yes. WUCOLS rates Madagascar periwinkle 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, moderate water 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.

Can Madagascar periwinkle survive California winters?

Madagascar periwinkle is a tender perennial that can persist in frost-free gardens. Where winter frost occurs, use it as warm-season bedding or provide protection. A cool-season decline should not automatically trigger more watering.

Why did my periwinkle suddenly wilt and die?

Wilting while the soil is damp calls for inspecting the roots and stem base, since this plant can suffer root and stem diseases. Check drainage before adding water. Identify the cause before deciding whether the same site is suitable for a replacement.

Is Madagascar periwinkle the same as the groundcover vinca?

No, common vinca groundcover belongs to a different genus, Vinca, despite the similar nickname. Madagascar periwinkle is an upright, warm-season bloomer rather than a trailing evergreen groundcover. Their water needs and growth habits differ.

Why aren't my periwinkles flowering much in cool weather?

Its main flowering season is the warm part of the year, and frost stops the display. Extra water will not remove that cold-weather limit. Only plants that survive winter can resume growth in a later season.

Can Madagascar periwinkle handle full desert sun?

Madagascar periwinkle accepts full sun, but monitor moisture and drainage carefully at a hot site. WUCOLS rates it moderate water in the high desert. It marks the low desert as not suited, so choose another bedding plant there.

More plant watering guides

Bigleaf LupineSnowy WoodrushBlue Potato BushHybrid MagnoliasKobus MagnoliaLily MagnoliaOyama MagnoliaSaucer Magnolia

Sources