WateringTimesWatering plan, $19
Herniaria glabra, WUCOLS IV

How often to water green carpet in California

In July in the Central Valley, established green carpet 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. Green carpet, or rupturewort, is a flat perennial that spreads into a dense mat of tiny bright green leaves only 1 to 3 inches tall. The foliage turns bronze in winter, and its tiny green flowers in late spring are barely visible. It fills gaps between stepping stones and works as a small lawn substitute in sun or part shade with well-drained soil.

Ground coverRated for 4 of 6 zones

How often to water green carpet, 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 green carpet 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 an inch down beneath the mat in summer means the carpet needs water
  • Bronze tones on the leaves in winter are normal seasonal color, not drought
  • Patches yellowing and thinning in soil that stays wet point to poor drainage rather than thirst
  • Damaged, dead foliage after winter calls for a spring trim, not extra water

How to water it

  • Water the whole mat evenly with a low sprinkler or drip line, wetting the top 4 to 6 inches of soil
  • Let the surface dry slightly between waterings, then water again before the mat dries out
  • Plant in loam or sand that drains well, in full sun or part shade
  • Trim off damaged foliage in spring so fresh growth fills in
  • Water a wider area as the mat spreads, up to 2 or 3 feet across

Through the seasons

Water new plantings regularly until the mat knits together. It stays evergreen or semi-evergreen, takes on bronze tones in winter, and its tiny flowers appear from late spring into early summer. Irrigation matters most in the warm, dry months. Winter rain usually covers it on the coast and in the Central Valley. On the north-central coast, WUCOLS gives green carpet a high water rating. The Central Valley, the south coast and South Inland all carry a moderate water rating. WUCOLS marks it as not suited to the high desert or the low desert.

In pots

Green carpet suits a shallow pot, a trough or the edge of a mixed container, where its trailing stems soften the rim. Use a well-drained, sandy mix and a pot with drainage holes. In summer heat, check the mix every day or two and water when the top inch is dry. Let excess water run out, then empty the saucer. In winter, water lightly, letting the mix dry a little between waterings.

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

Green Carpet: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.60.40.780.78––
Feb0.840.650.810.87––
Mar1.391.091.151.3––
Apr1.881.521.41.61––
May2.332.081.611.95––
Jun2.582.481.742.29––
Jul2.582.671.982.51––
Aug2.382.391.862.33––
Sep1.981.81.491.86––
Oct1.391.181.151.33––
Nov0.740.560.840.9––
Dec0.50.340.650.68––
Year19.217.1115.518.41––

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 green carpet. Plants that drink alike can share one valve and one schedule.

Star 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 JulyStrawberriesFragaria spp. & cvs. (CA native and non-natives species)moderate water, Central Valley2.67 gal/sq ft in JulyCarpet BugleAjuga reptans (shade)moderate water, Central Valley2.67 gal/sq ft in JulyGreen Supreme ManzanitaArctostaphylos uva-ursi 'Green Supreme'moderate water, Central Valley2.67 gal/sq ft in JulyMassachusetts ManzanitaArctostaphylos uva-ursi 'Massachusetts'moderate water, Central Valley2.67 gal/sq ft in JulySerbian BellflowerCampanula poscharskyanamoderate water, Central Valley2.67 gal/sq ft in JulyBunchberryCornus canadensismoderate water, Central Valley2.67 gal/sq ft in JulyKenilworth IvyCymbalaria muralismoderate water, Central Valley2.67 gal/sq ft in JulyCranesbillGeranium spp.moderate water, Central Valley2.67 gal/sq ft in JulySpotted DeadnettleLamium maculatummoderate water, Central Valley2.67 gal/sq ft in JulyLemon BalmMelissa officinalismoderate water, Central Valley2.67 gal/sq ft in JulyJapanese SpurgePachysandra terminalismoderate water, Central Valley2.67 gal/sq ft in JulyMoss PinkPhlox subulatamoderate water, Central Valley2.67 gal/sq ft in JulySpring CinquefoilPotentilla neumannianamoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

Rated lower than green carpet 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 JulyLantanaLantana camara ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyJunipersJuniperus 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 JulySagebrushArtemisia spp. (shrubby)low 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 JulyGround Morning GloryConvolvulus mauritanicuslow water, Central Valley1.07 gal/sq ft in JulyRock CotoneasterCotoneaster horizontalislow water, Central Valley1.07 gal/sq ft in JulySouth African GeraniumPelargonium sidoideslow water, Central Valley1.07 gal/sq ft in JulyLippia GroundcoverPhyla nodiflora (Lippia nodiflora) cvs.low water, Central Valley1.07 gal/sq ft in JulyRock SoapwortSaponaria ocymoideslow water, Central Valley1.07 gal/sq ft in JulyMother of ThymeThymus praecoxlow water, Central Valley1.07 gal/sq ft in JulyVancouver Jade BearberryArctostaphylos uva-ursi 'Vancouver Jade'low water, Central Valley1.07 gal/sq ft in JulyTrailing LantanaLantana montevidensis (sellowiana) ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyGermanderTeucrium chamaedrys ssp. & cvs.low 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 green carpet, 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 green carpet in summer?

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

In July in the Central Valley, established green carpet 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 green carpet change across California?

Yes. WUCOLS rates green carpet separately for each of the six California climate zones: high 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 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.

Can I use green carpet as a lawn substitute?

Yes, for small areas. It forms a dense, low, evergreen carpet and is well suited to the spaces between stepping stones. Use stepping stones where people walk often.

Why is my green carpet turning bronze?

The tiny leaves naturally take on bronze tones in winter. The bright green color returns with new growth in spring. Trim off any damaged patches then.

Does green carpet flower?

Yes, but the tiny green flowers from late spring to early summer blend into the foliage and are hard to see. It is grown for its leaves.

Can you overwater green carpet?

Yes. It needs well-drained soil, and ground that stays soggy thins the mat. Let the surface dry slightly between waterings.

Does green carpet grow in shade?

It grows in full sun, part shade or filtered sun. Choose a spot that also drains well.

More plant watering guides

Blue SedgeWestern CatalpaCedar of LebanonChinese HackberryPerennial CornflowerRoman ChamomileItalian ClematisNew Zealand Cabbage Tree

Sources