How often to water umbrella catalpa in California
In July on the north-central coast, established umbrella catalpa in loam needs a deep soak only about once a month or less: about 55 gallons each time under a 10 foot canopy. WUCOLS lists umbrella catalpa under Catalpa bungei, a deciduous Chinese tree with large, often lobed leaves. Pale pink, trumpet-shaped flowers with spotted throats are followed by long, bean-like pods. Young trees need deep, unhurried soakings until their roots spread. WUCOLS has rated it only for the north-central coast, so elsewhere let soil checks guide watering.
How often to water umbrella catalpa, 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
- Dry soil several inches down around a young catalpa's root ball in summer calls for a deep soak
- Large leaves torn into strips after strong wind show wind damage rather than thirst
- Branches wilting while the soil is still moist warrant a check for verticillium wilt, a disease this tree can get, before you add water
- New growth that dies back after a late spring frost points to frost damage rather than dry soil
- Soil that stays soggy for days after a soak calls for better drainage, since this tree needs moist but well-drained soil
How to water it
- Water a young umbrella catalpa across its root ball and the soil just beyond it, moving the wet area outward as the crown widens
- Soak slowly so water reaches deep into the root zone, then let the top few inches dry before the next soak
- Plant in porous, moist but well-drained soil, away from low spots where water stands after rain
- Use drip or a slow hose under the canopy rather than overhead spray, keeping the trunk base dry
- Spread wood chip mulch under the spreading crown, keeping it a few inches from the trunk
Through the seasons
A new umbrella catalpa needs deep soakings through its first summers while roots grow out from the nursery ball. Once established, it can go longer between soaks. The tree is bare through winter, leafs out in spring and flowers in late spring or early summer. Soil checks matter most from spring through summer. Winter rain covers the cool months on the north-central coast, where WUCOLS rates it low water. WUCOLS has not evaluated it for the Central Valley, the south coast, South Inland, the high desert or the low desert.
In pots
A young catalpa still in its nursery container dries out much faster than a tree in the ground. Probe the container 2 to 3 inches down every few days in summer heat, and daily during a hot spell. Water until it runs from the drainage holes, then empty the saucer. Set the container where afternoon sun does not bake its sides. Plant it out while it is young so the roots can spread. After leaf fall the bare tree uses little water, so let the mix dry a little more between soakings.
- A year
- no figure
- Reference
- Sacramento climate table
- Counts
- Plant need, before sprinkler losses
WUCOLS lists Umbrella Catalpa as not evaluated for the Central Valley zone, so no monthly figure is computed here.
Monthly water need by climate zone
Umbrella Catalpa: gallons per square foot per month, by WUCOLS climate zone
| Month | N. Coast | C. Valley | S. Coast | S. Inland | Hi Desert | Lo Desert |
|---|---|---|---|---|---|---|
| Jan | 0.15 | – | – | – | – | – |
| Feb | 0.21 | – | – | – | – | – |
| Mar | 0.35 | – | – | – | – | – |
| Apr | 0.47 | – | – | – | – | – |
| May | 0.58 | – | – | – | – | – |
| Jun | 0.64 | – | – | – | – | – |
| Jul | 0.64 | – | – | – | – | – |
| Aug | 0.6 | – | – | – | – | – |
| Sep | 0.5 | – | – | – | – | – |
| Oct | 0.35 | – | – | – | – | – |
| Nov | 0.19 | – | – | – | – | – |
| Dec | 0.12 | – | – | – | – | – |
| Year | 4.8 | – | – | – | – | – |
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 umbrella catalpa. Plants that drink alike can share one valve and one schedule.
Hawthorn MapleAcer crataegifoliumnot rated, Central Valleyno Central Valley rating
Mountain MapleAcer glabrumnot 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 ratingTurn this into minutes on your water days
Every city page has a calculator that takes umbrella catalpa, 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 umbrella catalpa need per day?
In July on the north-central coast, established umbrella catalpa needs about 1.6 gallons a day under a 10 foot canopy and about 6.5 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 umbrella catalpa change across California?
Yes. WUCOLS rates umbrella catalpa separately for each of the six California climate zones: low water in the North-Central Coastal zone, not evaluated in the Central Valley zone, not evaluated in the South Coastal zone, not evaluated 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.
Is an umbrella catalpa the same as Catalpa bungei?
Often not. The round-headed, grafted tree sold as umbrella catalpa is a dwarf clone of Catalpa bignonioides called 'Nana'. The nursery trade, especially in North America, has long labeled it Catalpa bungei. True Catalpa bungei is a Chinese species with pink flowers.
Why does my umbrella catalpa never flower?
If it is the grafted 'Nana' form, that is normal: unpruned grafted trees flower rarely and sparsely. True Catalpa bungei does flower, though it is often shy to set seed.
What are the shoots growing from the base of my catalpa?
They are suckers. On a grafted umbrella catalpa they come from the rootstock, and if left they can overtake the grafted head. Cut them off where they start.
Why do my catalpa's leaves smell bad?
True Catalpa bungei has unpleasant-smelling leaves, and in China it was known in gardens as the stinking tree. The smell is normal and has nothing to do with watering.
Why do the long pods stay on my catalpa?
The bean-like seed pods are persistent and can still hang on the branches when the next summer's flowers open. They are normal and need no change in watering.
Is umbrella catalpa frost hardy?
It is a hardy tree once its wood has ripened. Late spring frosts have killed trees, and young trees need protection from them. Cover a young tree when a late frost is forecast.
More plant watering guides
Sources
- WUCOLS IV plant water use classification for Catalpa bungei, 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