How often to water filbert in California
In July on the north-central coast, established filbert in loam needs a deep soak only about once a month or less: about 55 gallons each time under a 10 foot canopy. Filbert is a large deciduous shrub, sometimes trained as a small tree, grown for edible nuts wrapped in a long, tubular husk. Pale yellow catkins dangle from bare twigs in late winter, and broad leaves follow. It grows in most well-drained soils in sun or part shade, and planting two varieties together helps it set nuts.
How often to water filbert, 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 6 inches or more down beneath the branches in a long, dry summer means a deep soak is due
- Leaves wilting and curling at the edges in a hot spell can indicate the roots have dried out
- Yellowing leaves over soil that stays wet point to poor drainage, since filbert needs well-drained ground
- White, powdery patches on the leaves point to powdery mildew rather than thirst
- Swollen, distorted buds point to gall mites, not to a watering problem
How to water it
- Water the root zone under the branches with drip or a soaker instead of spraying the foliage
- Wet the soil about a foot deep, then let it dry well down before the next soaking
- Keep a bare, weed-free circle about 2 feet wide around the trunk
- Plant in well-drained soil, anything from clay to sand, in sun or part shade
- Move the watering ring outward as the shrub spreads, out to the tips of the branches
Through the seasons
Water a young filbert regularly through its first summer or two while roots spread. Catkins hang from bare twigs in late winter, before the leaves open, and the nuts follow. On the north-central coast, winter rain covers the dormant months, and an established shrub needs only an occasional deep soak in a dry summer. WUCOLS rates filbert low water on the north-central coast. WUCOLS marks it as not suited to the Central Valley, the south coast, South Inland, the high desert or the low desert.
In pots
Filbert becomes a large shrub of 8 feet or more, so a container suits only a young plant before it goes in the ground. Use a deep pot with drainage holes and a well-drained, loam-based mix. In summer, feel the mix a couple of inches down every few days and water once it is dry there. Let water drain through, then empty the saucer. After the leaves drop, water only when the mix is nearly dry.
- A year
- no figure
- Reference
- Sacramento climate table
- Counts
- Plant need, before sprinkler losses
WUCOLS lists Filbert as not suited to this region for the Central Valley zone, so no monthly figure is computed here.
Monthly water need by climate zone
Filbert: 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 suited to this region in the Central Valley, like filbert. Plants that drink alike can share one valve and one schedule.
Chenille PlantAcalypha hispidanot rated, Central Valleyno Central Valley rating
CopperleafAcalypha wilkesiananot rated, Central Valleyno Central Valley rating
Sugar MapleAcer saccharumnot rated, Central Valleyno Central Valley rating
Queensland KauriAgathis robustanot rated, Central Valleyno Central Valley rating
CherimoyaAnnona cherimolanot rated, Central Valleyno Central Valley rating
Yellow Bell BauhiniaBauhinia tomentosanot rated, Central Valleyno Central Valley rating
Purple Orchid TreeBauhinia variegata (purpurea)not rated, Central Valleyno Central Valley rating
ToogBischofia javanicanot rated, Central Valleyno Central Valley rating
Magic FlowerCantua buxifolianot rated, Central Valleyno Central Valley rating
Clustered Fishtail PalmCaryota mitisnot rated, Central Valleyno Central Valley rating
White SapoteCasimiroa edulisnot rated, Central Valleyno Central Valley rating
Hawaiian TiCordyline fruticosa (Cordyline terminalis)not rated, Central Valleyno Central Valley rating
Spotted GumCorymbia maculata (Eucalyptus maculata)not rated, Central Valleyno Central Valley rating
Dove TreeDavidia involucratanot rated, Central Valleyno Central Valley rating
Royal PoincianaDelonix regianot rated, Central Valleyno Central Valley rating
Triangle PalmDypsis decaryinot rated, Central Valleyno Central Valley ratingTurn this into minutes on your water days
Every city page has a calculator that takes filbert, 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 filbert need per day?
In July on the north-central coast, established filbert 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 filbert change across California?
Yes. WUCOLS rates filbert separately for each of the six California climate zones: low water in the North-Central Coastal zone, not suited to this region 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 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.
Why is my filbert not producing nuts?
Filberts set nuts more reliably when at least two varieties grow together for cross pollination. Squirrels also take the nuts. Plant a second variety nearby and pick the crop promptly.
How do I prune a filbert for nuts?
Grow it as an open, goblet-shaped bush. In August, break side shoots halfway along their length. Shorten them to 3 or 4 buds in late winter while the catkins shed pollen. Remove up to a third of old, crowded shoots when needed.
Does purple-leaved filbert produce nuts?
Yes. The purple-leaved form has deep purple leaves up to about 5 inches long and still bears edible nuts hidden in tubular husks. It can grow larger than green forms, to about 20 feet.
Can you overwater filbert?
Yes. It needs well-drained soil, and ground that stays wet harms the roots. On the north-central coast, winter rain plus an occasional deep summer soak usually covers it.
What pests attack filbert?
Caterpillars, aphids, sawflies and gall mites can all appear, and powdery mildew is possible. None of these is fixed by more water, so check the leaves and buds before changing irrigation.
More plant watering guides
Sources
- WUCOLS IV plant water use classification for Corylus maxima, 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