WateringTimesWatering plan, $19
Pinus coulteri, WUCOLS IV

How often to water Coulter pine in California

In July in the Central Valley, established Coulter pine in loam needs a deep watering about every 20 days: about 55 gallons each time under a 10 foot canopy, about 19 gallons a week. Coulter pine is a California native of dry, rocky coastal mountains, with long, stiff, bluish-gray needles in bundles of three and dark, furrowed bark. It bears the largest cones of any pine, heavy and armed with curved, talon-like spines. Once established it needs little summer water, and it wants sun and well-drained soil, doing best near the coast.

TreeCalifornia nativeRated for 5 of 6 zones

How often to water Coulter pine, month by month

Your city
Canopy width
10 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 Coulter pine 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 under the branches, 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 canopy width

A tree with its canopy width marked across the widest branches and the circle under it shaded blue

Measure across the branches, from the tips of the outer leaves on one side to the tips on the other. A tape works, or pace it out.

Water the whole circle under the branches, shown in blue. The gallons here cover that circle.

A wider canopy means more gallons each watering, not more waterings. While the tree is young, measure again each spring.

How to tell it needs water

  • A young Coulter pine is ready for a deep soak when soil at the root ball edge has dried about 6 inches down
  • Branch tips wilting and browning with resin oozing at the bend can point to pitch canker rather than thirst
  • Pitch tubes or boring dust on the trunk point to bark beetles, which favor drought-stressed pines
  • A thinning crown with mushrooms at the base on a tree in a watered lawn warns of root rot
  • Needles yellowing across a young tree's crown in a long heat wave can show it ran dry

How to water it

  • Water a new tree deeply and slowly over the root ball and just beyond, then taper off as it establishes
  • Once it is established, give only an occasional deep summer soak in hot inland areas
  • Plant in full sun in well-drained soil, away from lawns and frequent sprinklers
  • Site it away from paths, patios and parking, since the huge cones are dangerous when they fall
  • Leave fallen needles as mulch over the root zone, keeping the trunk base clear

Through the seasons

A newly planted Coulter pine needs occasional deep soakings through its first two summers, ideally after a fall planting. After that it needs little summer water, though high desert trees want more. It stays evergreen and grows roughly a foot a year when young. Rain usually covers the cool months on the coast and in the Central Valley. Across the north-central coast, the Central Valley, the south coast and South Inland, WUCOLS rates Coulter pine low water. The high desert gets a moderate water rating, and the low desert is marked not suited.

In pots

Coulter pine grows into a large tree, so a pot only suits a seedling for a short time. Use a deep container with a gritty mix, and water when it is dry 2 to 3 inches down. Let it drain fully before emptying the saucer. A seedling in a dark pot can overheat in summer sun, so shade the pot itself. Plant it out young, ideally in fall so winter rain helps it settle.

1 Your climate zone six WUCOLS zones, each from its own reference city
1.07gal per sq ft in JulyLow water use in the Central Valley zone
A year
6.84 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.761.52.33.00.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.761.52.33.00.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

Coulter Pine: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.310.310.74–
Feb0.210.260.320.350.93–
Mar0.350.430.460.521.46–
Apr0.470.610.560.641.89–
May0.580.830.640.782.39–
Jun0.640.990.690.922.85–
Jul0.641.070.7913.04–
Aug0.60.950.740.932.79–
Sep0.50.720.60.742.14–
Oct0.350.470.460.531.46–
Nov0.190.220.330.360.93–
Dec0.120.140.260.270.65–
Year4.86.846.27.3721.27–

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 low water in the Central Valley, like Coulter pine. Plants that drink alike can share one valve and one schedule.

Olive TreesOlea europaea ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyFig TreesFicus carica ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyCrape MyrtleLagerstroemia spp., hybrids & cvs.low water, Central Valley1.07 gal/sq ft in JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyPomegranate TreesPunica granatumlow water, Central Valley1.07 gal/sq ft in JulyEucalyptusEucalyptus polyanthemoslow water, Central Valley1.07 gal/sq ft in JulyPine TreesPinus canariensislow water, Central Valley1.07 gal/sq ft in JulyJunipersJuniperus spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyTexas Red OakQuercus buckleyilow water, Central Valley1.07 gal/sq ft in JulyPortuguese OakQuercus faginealow water, Central Valley1.07 gal/sq ft in JulySoapbark TreeQuillaja saponarialow water, Central Valley1.07 gal/sq ft in JulyNecklace TreeSophora affinislow water, Central Valley1.07 gal/sq ft in JulyBailey AcaciaAcacia baileyanalow water, Central Valley1.07 gal/sq ft in JulySilver WattleAcacia dealbatalow water, Central Valley1.07 gal/sq ft in JulyGreen WattleAcacia decurrenslow water, Central Valley1.07 gal/sq ft in JulySydney Golden WattleAcacia longifolialow 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 Coulter pine, 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 Coulter pine in summer?

In July, established Coulter pine in loam needs a deep watering about every 20 days in the Central Valley, about every 27 days on the south coast and about every 22 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 Coulter pine need per day?

In July in the Central Valley, established Coulter pine needs about 2.7 gallons a day under a 10 foot canopy and about 11 gallons a day under a 20 foot canopy. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for Coulter pine change across California?

Yes. WUCOLS rates Coulter pine separately for each of the six California climate zones: low water in the North-Central Coastal zone, low water in the Central Valley zone, low water in the South Coastal zone, low 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.

Are Coulter pine cones dangerous?

They are the largest and heaviest cones of any pine, about as heavy as a quart jar of syrup, and armed with curved spines. Do not plant it over paths, patios or parking. Wear gloves when you pick them up.

Is Coulter pine native to California?

Yes. It grows from Baja California north through the coast ranges to the eastern San Francisco Bay Area, among chaparral, oak woodland and lower conifer forest. It does not occur in the interior mountains.

How fast does Coulter pine grow?

It grows about 10 feet in its first 10 years and eventually reaches 50 to 80 feet. Give it room for a crown up to 40 feet wide.

Why are my Coulter pine branch tips dying?

Pitch canker, a fungal disease that affects most California native pines, girdles branches so their tips yellow and brown, often with resin at the infection. Removing infected branches can help. Other insects and diseases can look similar, so have a sample checked if unsure.

Are Coulter pine nuts edible?

Yes, the seeds inside the big cones are edible. Getting them out of the heavy, spiny cones takes thick gloves and patience.

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Sources