How often to water golden trumpet vine in California
In July on the south coast, established golden trumpet vine in loam needs a deep watering about every 11 days: about 2.2 gallons each time for a plant 2 feet across, about 1.4 gallons a week. Golden trumpet vine is a tropical evergreen climber from Central and South America, grown for large, bright yellow trumpet flowers from summer into fall. Its glossy, leathery leaves grow in whorls along long, sprawling stems that must be tied to a support. It needs full sun, frost-free warmth, steady moisture and good drainage.
How often to water golden trumpet vine, 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 the plant covers, and skip a watering after a good soaking rain.
How to tell it needs water
- Soft, drooping stem tips at midday, with the soil dry an inch or two down, show the vine is thirsty
- Yellowing leaves over soil that stays soggy point to poor drainage, which this vine needs as much as moisture
- Blackened, limp leaves after a cold night mean chill or frost damage, not drought
- Few flowers on a vine in partial shade reflect too little sun rather than too little water
- Fine webbing and pale speckling on the leaves point to spider mites, and tiny white flying insects to whitefly
How to water it
- Water along the base of the trellis with drip or a soaker so the whole root zone stays evenly moist
- Soak the soil about 8 inches deep in the growing season, then water again once the top inch or two has dried
- Plant in fertile, loamy soil that drains freely, against a warm, sheltered wall in full sun
- Cover the root area with mulch to hold moisture, keeping it off the stems
- Tie new stems to the support as they grow, and widen the watered strip as the vine spreads
Through the seasons
Water a new vine regularly while it roots in and starts to climb. It is evergreen, grows fast in warm weather and flowers from summer into fall, so the dry months are when irrigation matters most. Give it less water in winter, when growth slows, and protect it from frost, which it cannot take. Prune in late winter or early spring if needed. WUCOLS rates golden trumpet vine moderate water on the south coast. WUCOLS marks it as not suited to the north-central coast, the Central Valley, South Inland, the high desert or the low desert.
In pots
Golden trumpet vine grows well in a large container with a trellis, and a pot can be moved under cover before frost. Use a loam-based, well-drained mix and a pot with drainage holes. While it grows and flowers, water freely, checking the mix daily in summer heat and watering when the top inch is dry. Let it drain, then empty the saucer. Indoors for winter, keep it in bright light and water sparingly.
- A year
- no figure
- Reference
- Sacramento climate table
- Counts
- Plant need, before sprinkler losses
WUCOLS lists Golden Trumpet Vine as not suited to this region for the Central Valley zone, so no monthly figure is computed here.
Monthly water need by climate zone
Golden Trumpet Vine: gallons per square foot per month, by WUCOLS climate zone
| Month | N. Coast | C. Valley | S. Coast | S. Inland | Hi Desert | Lo Desert |
|---|---|---|---|---|---|---|
| Jan | – | – | 0.78 | – | – | – |
| Feb | – | – | 0.81 | – | – | – |
| Mar | – | – | 1.15 | – | – | – |
| Apr | – | – | 1.4 | – | – | – |
| May | – | – | 1.61 | – | – | – |
| Jun | – | – | 1.74 | – | – | – |
| Jul | – | – | 1.98 | – | – | – |
| Aug | – | – | 1.86 | – | – | – |
| Sep | – | – | 1.49 | – | – | – |
| Oct | – | – | 1.15 | – | – | – |
| Nov | – | – | 0.84 | – | – | – |
| Dec | – | – | 0.65 | – | – | – |
| Year | – | – | 15.5 | – | – | – |
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 10
Rated not suited to this region in the Central Valley, like golden trumpet vine. Plants that drink alike can share one valve and one schedule.
Pelican FlowerAristolochia giganteanot rated, Central Valleyno Central Valley rating
Wax PlantHoya carnosanot rated, Central Valleyno Central Valley rating
Flame VinePyrostegia venustanot rated, Central Valleyno Central Valley rating
Cup-of-Gold VineSolandra maximanot rated, Central Valleyno Central Valley rating
Madagascar JasmineStephanotis floribundanot rated, Central Valleyno Central Valley rating
Black-Eyed Susan VineThunbergia alatanot rated, Central Valleyno Central Valley rating
Sky Flower VineThunbergia grandifloranot rated, Central Valleyno Central Valley rating
Coral VineAntigonon leptopusnot rated, Central Valleyno Central Valley rating
Queen's WreathPetrea volubilisnot rated, Central Valleyno Central Valley rating
Beauverd's Widow's-ThrillKalanchoe beauverdiinot rated, Central Valleyno Central Valley ratingTurn this into minutes on your water days
Every city page has a calculator that takes golden trumpet vine, 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 golden trumpet vine need per day?
In July on the south coast, established golden trumpet vine needs about 0.2 gallons a day for a plant 2 feet across and about 0.8 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 golden trumpet vine change across California?
Yes. WUCOLS rates golden trumpet vine separately for each of the six California climate zones: not suited to this region in the North-Central Coastal zone, not suited to this region in the Central Valley zone, moderate water in the South Coastal zone, not suited to this region 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.
Is golden trumpet vine poisonous?
Yes. All parts are harmful if eaten, and the sap irritates skin and eyes. It is also harmful to dogs and cats. Wear gloves when pruning or tying stems.
Can golden trumpet vine survive frost?
No. It needs a frost-free spot outdoors. Where frost is likely, grow it in a container, cut it back and move it to a bright indoor spot before the first freeze.
Does golden trumpet vine climb on its own?
Only loosely. Its long stems sprawl and twine, so tie them to a trellis, arbor or wires as they grow. Left unsupported, it forms a sprawling shrub.
Can you overwater golden trumpet vine?
Yes. It wants ample moisture, but it also needs good drainage, and soggy soil weakens the roots. Water freely in summer and sparingly in winter.
When does golden trumpet vine bloom?
It flowers from summer into fall, with clusters of trumpets up to about 3 1/2 inches long at the branch tips. It grows best in full sun.
More plant watering guides
Sources
- WUCOLS IV plant water use classification for Allamanda cathartica, 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