How often to water mountain maple in California
In July on the north-central coast, established mountain maple in loam needs a deep watering about every 13 days: about 55 gallons each time under a 10 foot canopy, about 29 gallons a week. Mountain maple, also called Rocky Mountain maple, is a deciduous shrub or small tree native to western North America, including California. It usually grows multi-trunked to 12 to 30 feet. Red twigs stand out in winter, red winged fruit hangs in late summer and fall, and leaves turn yellow to red. It likes semi-shade and soil rich in organic matter.
How often to water mountain maple, month by month
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.
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.
How to tell it needs water
- Soil dry 3 inches down under the canopy in summer means mountain maple needs a deep watering
- Leaf edges browning in afternoon sun can follow dry soil and too much exposure
- Leaves dropping early in late summer can indicate drought stress
- Yellowing leaves over soggy, poorly drained soil point to too much water
How to water it
- Water at the root zone with drip or a soaker
- Soak about a foot deep, then let the top few inches dry
- Plant in semi-shade to shade, sheltered from wind and afternoon sun
- Work in plenty of organic matter at planting
- Prune only in summer, since it bleeds sap in late winter and spring
Through the seasons
Water a young plant regularly through its first summers. Established plants want moderate, deep soaks in dry months and shade from afternoon sun. Leaves color yellow to red in fall, red fruit hangs on into autumn, and red twigs brighten the bare branches through winter. On the north-central coast, WUCOLS rates mountain maple moderate water. WUCOLS marks it as not suited to the south coast, South Inland or the low desert, and has not evaluated it for the Central Valley or the high desert.
In pots
Mountain maple can grow in a large container while young, though it belongs in the ground long term. Use a rich, well-drained mix with plenty of organic matter. Water when the top couple of inches dry, until it drains out the bottom. In summer, keep the pot shaded in the afternoon and check it every few days. Empty the saucer. In winter, while it is bare, water only when the mix dries.
- A year
- no figure
- Reference
- Sacramento climate table
- Counts
- Plant need, before sprinkler losses
WUCOLS lists Mountain Maple as not evaluated for the Central Valley zone, so no monthly figure is computed here.
Monthly water need by climate zone
Mountain Maple: gallons per square foot per month, by WUCOLS climate zone
| Month | N. Coast | C. Valley | S. Coast | S. Inland | Hi Desert | Lo Desert |
|---|---|---|---|---|---|---|
| Jan | 0.37 | – | – | – | – | – |
| Feb | 0.53 | – | – | – | – | – |
| Mar | 0.87 | – | – | – | – | – |
| Apr | 1.18 | – | – | – | – | – |
| May | 1.46 | – | – | – | – | – |
| Jun | 1.61 | – | – | – | – | – |
| Jul | 1.61 | – | – | – | – | – |
| Aug | 1.49 | – | – | – | – | – |
| Sep | 1.24 | – | – | – | – | – |
| Oct | 0.87 | – | – | – | – | – |
| Nov | 0.47 | – | – | – | – | – |
| Dec | 0.31 | – | – | – | – | – |
| Year | 12 | – | – | – | – | – |
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 not evaluated in the Central Valley, like mountain maple. Plants that drink alike can share one valve and one schedule.
Hawthorn MapleAcer crataegifoliumnot rated, Central Valleyno Central Valley rating
Miyabe MapleAcer miyabeinot rated, Central Valleyno Central Valley rating
Everglades PalmAcoelorraphe wrightiinot rated, Central Valleyno Central Valley rating
Pink CedarAcrocarpus fraxinifoliusnot rated, Central Valleyno Central Valley rating
YellowwoodAfrocarpus falcatus (Podocarpus falcatus)not rated, Central Valleyno Central Valley rating
New Caledonian PineAraucaria columnaris (A. cookii)not rated, Central Valleyno Central Valley rating
Formosa Sugar PalmArenga englerinot rated, Central Valleyno Central Valley rating
NeemAzadirachta indicanot rated, Central Valleyno Central Valley rating
Bismarck PalmBismarckia nobilisnot rated, Central Valleyno Central Valley rating
American HornbeamCarpinus caroliniananot rated, Central Valleyno Central Valley rating
Japanese HornbeamCarpinus japonicanot rated, Central Valleyno Central Valley rating
American YellowwoodCladrastis kentukeanot rated, Central Valleyno Central Valley rating
Pagoda DogwoodCornus alternifolianot rated, Central Valleyno Central Valley rating
Giant DogwoodCornus controversanot rated, Central Valleyno Central Valley rating
Butterfly PalmDypsis lutescens (Areca)not rated, Central Valleyno Central Valley rating
Abyssinian Coral TreeErythrina abyssinicanot rated, Central Valleyno Central Valley ratingTurn this into minutes on your water days
Every city page has a calculator that takes mountain maple, 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 much water does mountain maple need per day?
In July on the north-central coast, established mountain maple needs about 4.1 gallons a day under a 10 foot canopy and about 16 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 mountain maple change across California?
Yes. WUCOLS rates mountain maple separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, not evaluated in the Central Valley zone, not suited to this region in the South Coastal zone, not suited to this region in the South Inland zone, not evaluated 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.
Is mountain maple native to California?
Yes, it is native across western North America, including California. It does best in conditions like its native habitat. Shade and organic soil suit it.
When should I prune mountain maple?
Prune in summer after the leaves have fully developed. Pruning in late winter or early spring makes it bleed sap. Keep pruning light.
How big does mountain maple get?
It grows 12 to 30 feet tall and 10 to 20 feet wide. It is often multi-trunked. In crowded stands it gets tall and spindly.
Can mountain maple take full sun?
It performs best in semi-shade to shade. Protect it from afternoon sun and strong wind. Sun dries its soil faster.
What soil does mountain maple need?
It grows in sandy, loamy or clay acidic soils. It prefers good drainage and lots of organic matter. Mulch helps.
More plant watering guides
Sources
- WUCOLS IV plant water use classification for Acer glabrum, the University of California survey California agencies use for landscape plan reviewRead August 23, 2026 on wucols.ucdavis.edu
- Model Water Efficient Landscape Ordinance, adopted text and appendices, effective 2025-01-02 · monthly reference evapotranspiration per city, Appendix CRead August 23, 2026 on water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Water-Use-And-Efficiency/MWELO-Rulemaking/Final-MWELO-Text-and-Appendices_20250103.pdf
- UC Statewide IPM Program, irrigation scheduling using evapotranspirationRead September 30, 2026 on ipm.ucanr.edu/PMG/GARDEN/ENVIRON/evap.html
- Shaw and Pittenger, Landscape Irrigation System Evaluation and Management, UC Cooperative Extension, 2009Read September 30, 2026 on ucanr.edu/sites/default/files/2013-02/160836.pdf
- Pittenger, Water Management in Gardens and Landscapes, UC Riverside, 2017Read September 30, 2026 on ucanr.edu/sites/default/files/2017-03/258022.pdf