WateringTimesWatering plan, $19
Callistemon citrinus, WUCOLS IV

How often to water bottle brush in California

In July in the Central Valley, established bottle brush 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. Bottle brush, Callistemon citrinus, also called lemon bottlebrush, is a large evergreen shrub from southeastern Australia that can be trained as a small tree. Its red flower spikes appear year-round in coastal California, peaking from early summer through fall. Established plants are drought tolerant, but a young shrub needs deep soakings while its roots spread.

ShrubTreeRated for 5 of 6 zones

How often to water bottle brush, 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 bottle brush 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

  • When the soil 4 to 6 inches down at the root ball edge has dried, a young bottle brush is ready for a deep soak
  • Pale stippling or fine webbing on the leaves in hot, dusty weather can mean spider mites, which hit water-stressed plants hardest
  • Yellowing leaves on salty or strongly alkaline soil point to soil chemistry rather than thirst
  • Soil that stays soggy around the trunk for days after watering calls for better drainage, since it needs fairly well-drained ground
  • Coppery or pink new leaves are normal fresh growth that turns green as it matures, not a sign of stress

How to water it

  • Water a young bottle brush over its root ball and a band beyond it, widening the band as the canopy spreads
  • Soak slowly and deeply, then let the soil dry well down before the next soak
  • Use drip or a slow hose under the canopy instead of overhead spray, and keep the trunk base dry
  • Plant in full sun in fairly well-drained soil; poor soil is fine, but avoid spots where water pools
  • Mulch the root zone to keep dust down, and hose dust off the leaves in hot, dry weather to discourage spider mites

Through the seasons

Until a new bottle brush settles in, give it deep summer soakings and widen the wet ring as its branches spread. Established shrubs are drought tolerant and, outside the low desert, need only infrequent deep soaks. It stays evergreen, and its main flush of bloom in summer and fall is when soil checks matter most. It is cold hardy to about 20°F. Winter rain covers the cool months on the north-central coast, in the Central Valley and on the south coast. WUCOLS rates bottle brush low water on the north-central coast, in the Central Valley, on the south coast and in South Inland. It rates moderate water in the low desert, where summer heat calls for closer soil checks. WUCOLS marks it as not suited to the high desert.

In pots

Bottle brush can be grown in a container, and it takes pruning well, which keeps a potted plant to a manageable size. Probe the mix 2 inches down at the pot edge every few days in summer heat, and more often in low desert sun. Once it is dry at that depth, soak until water runs from the drainage holes, then empty the saucer. In winter it uses less water, so let the mix dry a little more between soakings. If the pot comes indoors for the cold months, give it bright light and check the leaves for spider mites and scale.

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
0.711.42.12.90.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.711.42.12.90.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

Bottle Brush: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.310.31–0.78
Feb0.210.260.320.35–0.93
Mar0.350.430.460.52–1.52
Apr0.470.610.560.64–1.95
May0.580.830.640.78–2.45
Jun0.640.990.690.92–2.79
Jul0.641.070.791–2.85
Aug0.60.950.740.93–2.6
Sep0.50.720.60.74–2.08
Oct0.350.470.460.53–1.49
Nov0.190.220.330.36–0.96
Dec0.120.140.260.27–0.68
Year4.86.846.27.37–21.08

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 bottle brush. Plants that drink alike can share one valve and one schedule.

LavenderLavandula spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRosemaryRosmarinus officinalislow water, Central Valley1.07 gal/sq ft in JulyBougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyOlive 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 JulyLantanaLantana camara ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria 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 JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySagebrushArtemisia spp. (shrubby)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 bottle brush, 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 bottle brush in summer?

In July, established bottle brush 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 bottle brush need per day?

In July in the Central Valley, established bottle brush 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 bottle brush change across California?

Yes. WUCOLS rates bottle brush 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, not suited to this region in the High and Intermediate Desert zone, moderate water in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Is bottle brush the same as Melaleuca?

Botanists now place this species in Melaleuca, as Melaleuca citrina. Many California nurseries still sell it as Callistemon citrinus. The care is the same under either name.

Can I prune bottle brush hard?

Yes. It is very tolerant of pruning, and old plants regrow when cut back hard into old wood. With patient pruning it can be trained as a single-trunk small tree or kept as a hedge.

Does bottle brush attract hummingbirds?

Yes. The flowers attract hummingbirds and bees, and birds also feed on its nectar and seed. Bloom on the coast can continue through much of the year.

Why are my bottle brush leaves turning yellow?

Leaf yellowing can occur when the soil is high in salt or very alkaline. A soil test will show whether that is the cause. Check drainage as well before changing how you water.

What are the woody beads along bottle brush stems?

They are the woody seed capsules left after flowering. They stay tight against the stems for many years and are normal. They say nothing about how much water the shrub needs.

Can bottle brush grow near the coast?

Yes. It tolerates near-coastal conditions, heat, poor soil and deer. In its native Australia it often grows in wet or swampy places, yet established plants are drought tolerant.

More plant watering guides

False Esparto GrassChinaberryAfrican BoxwoodSouth African GeraniumJerusalem SageCanary Island Date PalmDate PalmsLippia Groundcover

Sources