WateringTimesWatering plan, $19
Arenaria montana, WUCOLS IV

How often to water mountain sandwort in California

In July in the Central Valley, established mountain sandwort 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. Mountain sandwort is a low, evergreen, mat-forming perennial from southwestern Europe and Morocco, only a few inches tall and about a foot wide. Small, rich green leaves carry upright stems with pure white flowers in early summer. It grows best in poor, sandy soil and suits rock gardens, wall crevices and paving gaps. Good drainage matters more than rich soil.

PerennialRated for 4 of 6 zones

How often to water mountain sandwort, 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 mountain sandwort 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

  • The mat of mountain sandwort turning dull and soft while the soil is dry an inch down means it needs water
  • Leaves browning in afternoon sun in hot inland gardens point to heat stress
  • The mat rotting in the center after heavy rain points to poor drainage
  • A mat covered in white flowers in early summer is well watered

How to water it

  • Water at the base of the mat when the top inch of soil dries
  • Plant in full sun or part shade in poor, sandy, well-drained soil
  • Tuck it into wall crevices, paving gaps or a rock garden
  • Give it some afternoon shade in hot inland areas
  • Keep mulch and leaf litter off the mat

Through the seasons

Keep new plants moist until the mat begins to creep outward. After that, mountain sandwort likes moderate moisture during the long dry months. It stays evergreen and blooms in early summer. Winter rain usually covers its needs on the coast and in the Central Valley, so good drainage matters most then. WUCOLS rates mountain sandwort moderate water on the north-central coast, in the Central Valley, on the south coast and in South Inland. WUCOLS has not evaluated it for the high desert or the low desert.

In pots

Mountain sandwort spills over the edge of a shallow pot or trough. Use a gritty, sandy mix that drains fast. Give it a thorough soak once the surface inch feels dry. In summer heat, check every couple of days and move the pot out of harsh afternoon sun. Keep the saucer empty. In winter, water only when the mix dries, and keep the pot from sitting in rain.

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

Mountain Sandwort: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.78––
Feb0.530.650.810.87––
Mar0.871.091.151.3––
Apr1.181.521.41.61––
May1.462.081.611.95––
Jun1.612.481.742.29––
Jul1.612.671.982.51––
Aug1.492.391.862.33––
Sep1.241.81.491.86––
Oct0.871.181.151.33––
Nov0.470.560.840.9––
Dec0.310.340.650.68––
Year1217.1115.518.41––

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 16

Rated moderate water in the Central Valley, like mountain sandwort. 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 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 JulyEnglish DaisyBellis perennismoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

Rated lower than mountain sandwort 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 mountain sandwort, 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 mountain sandwort in summer?

In July, established mountain sandwort 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 mountain sandwort need per day?

In July in the Central Valley, established mountain sandwort 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 mountain sandwort change across California?

Yes. WUCOLS rates mountain sandwort 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, 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 does mountain sandwort bloom?

It blooms in early summer. Pure white flowers sit on short, upright stems. They cover the mat.

Where should I plant mountain sandwort?

It grows easily in a rock garden or in crevices in a wall or paving. Poor, sandy soil suits it best. It also works as edging or ground cover.

Does mountain sandwort need pruning?

No pruning is needed. It is generally free of pests and diseases. Pull weeds that creep into the mat.

How do I propagate mountain sandwort?

Grow it from seed, divide the mat, or take basal cuttings. Water new pieces gently. Plant them in gritty soil.

How big does mountain sandwort get?

It stays under about 4 inches tall. The mat spreads to about a foot wide. It takes a few years to fill in.

More plant watering guides

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Sources