How often to water otterbossie in California
In July in the low desert, established otterbossie in loam needs a deep watering about every 19 days: about 8.8 gallons each time for a plant 4 feet across, about 3.2 gallons a week. Otterbossie is the name WUCOLS uses for Gossypium harknessii, a shrub in the cotton genus, which belongs to the mallow family. WUCOLS rates it in only one California zone, the low desert, as a low water shrub. Time each watering by checking the soil, with deep soaks spaced well apart once the roots are established.
How often to water otterbossie, 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
- Soil still damp 2 inches down means otterbossie does not need water yet, even in desert heat
- Leaves wilting in the afternoon while the root zone is dry several inches down show it has gone too long between soaks
- Yellowing leaves over soil that stays wet point to more water than this shrub needs
- Wilting that persists after a deep soak can mean root damage rather than thirst, so check drainage before adding more water
How to water it
- Water a new shrub at the edge of its root ball with drip or a slow hose, soaking 12 to 18 inches deep
- Once roots are established, let the soil dry several inches down before the next soak
- Plant in soil that drains well, and avoid low spots where irrigation water collects
- Add emitters farther out as the shrub widens, so water reaches the spreading roots
- Keep it out of lawn sprinkler range and group it with other dry-climate shrubs
Through the seasons
A newly planted otterbossie needs regular deep soaks through its first warm season while roots spread into the surrounding soil. After that, water deeply but less often, using soil checks to time each soak. In the low desert, summer heat drives most of its water use, and the cooler months need far less. Winter rain is too sparse there to rely on. WUCOLS rates otterbossie low water in the low desert. WUCOLS has not evaluated it for the north-central coast, the Central Valley, the south coast, South Inland or the high desert.
In pots
If you keep otterbossie in a container, choose a large pot with drainage holes and a fast-draining mix. In low desert heat, pots dry far faster than garden soil. Through summer, check the mix 2 inches down every day or two, and water only once it is dry there. Water until it runs out the bottom, then empty the saucer. Shade the pot itself if it sits on hot paving. In winter, water only when the mix has dried well.
- A year
- no figure
- Reference
- Sacramento climate table
- Counts
- Plant need, before sprinkler losses
WUCOLS lists Otterbossie as not evaluated for the Central Valley zone, so no monthly figure is computed here.
Monthly water need by climate zone
Otterbossie: gallons per square foot per month, by WUCOLS climate zone
| Month | N. Coast | C. Valley | S. Coast | S. Inland | Hi Desert | Lo Desert |
|---|---|---|---|---|---|---|
| Jan | – | – | – | – | – | 0.31 |
| Feb | – | – | – | – | – | 0.37 |
| Mar | – | – | – | – | – | 0.61 |
| Apr | – | – | – | – | – | 0.78 |
| May | – | – | – | – | – | 0.98 |
| Jun | – | – | – | – | – | 1.12 |
| Jul | – | – | – | – | – | 1.14 |
| Aug | – | – | – | – | – | 1.04 |
| Sep | – | – | – | – | – | 0.83 |
| Oct | – | – | – | – | – | 0.6 |
| Nov | – | – | – | – | – | 0.38 |
| Dec | – | – | – | – | – | 0.27 |
| Year | – | – | – | – | – | 8.43 |
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 otterbossie. Plants that drink alike can share one valve and one schedule.
Formosa Sugar PalmArenga englerinot rated, Central Valleyno Central Valley rating
Chilean Feather BambooChusquea culeou (C. breviglumis)not rated, Central Valleyno Central Valley rating
BlackbrushColeogyne ramosissimanot rated, Central Valleyno Central Valley rating
Glaucous Scorpion VetchCoronilla valentina glaucanot rated, Central Valleyno Central Valley rating
Willowleaf CotoneasterCotoneaster salicifoliusnot rated, Central Valleyno Central Valley rating
Madagascar SagoCycas thouarsii (SHADE)not rated, Central Valleyno Central Valley rating
Irish HeathDaboecia cantabricanot rated, Central Valleyno Central Valley rating
Butterfly PalmDypsis lutescens (Areca)not rated, Central Valleyno Central Valley rating
Umbrella BambooFargesia murielaenot rated, Central Valleyno Central Valley rating
Blue Fountain BambooFargesia nitida (Sinarundinaria nitida) (BAMBOO)not rated, Central Valleyno Central Valley rating
Prickly HeathGaultheria mucronata (Pernettya mucronata)not rated, Central Valleyno Central Valley rating
Box-leaved HollyIlex crenatanot rated, Central Valleyno Central Valley rating
Bellyache BushJatropha gossypiifolianot rated, Central Valleyno Central Valley rating
Mountain LaurelKalmia latifolianot rated, Central Valleyno Central Valley rating
Barbados CherryMalpighia glabranot rated, Central Valleyno Central Valley rating
Siberian CypressMicrobiota decussatanot rated, Central Valleyno Central Valley ratingTurn this into minutes on your water days
Every city page has a calculator that takes otterbossie, 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 otterbossie need per day?
In July in the low desert, established otterbossie needs about 0.5 gallons a day for a plant 4 feet across and about 1.8 gallons a day for a plant 8 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 otterbossie change across California?
Yes. WUCOLS rates otterbossie separately for each of the six California climate zones: not evaluated 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, low water in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.
What is otterbossie?
It is Gossypium harknessii, listed under that name by WUCOLS. The plant is a woody cotton relative, and the cottons belong to the mallow family.
Can you overwater otterbossie?
Yes. WUCOLS rates it low water in the low desert, so the soil should dry several inches down between soaks. Ground that stays wet invites root trouble.
Does otterbossie need water in winter?
Much less than in summer. In the cool months, check the soil before each watering and skip it if the soil is still damp a few inches down.
How do I know when otterbossie needs water?
Dig down 2 to 4 inches near the outer edge of the shrub. If the soil is dry there in warm weather, give a deep soak, and if it is still damp, wait.
How should I plant otterbossie?
Plant it where the soil drains freely, away from lawn and beds that get frequent water. Keep a watering basin around it for the first season so each soak reaches the roots.
More plant watering guides
Sources
- WUCOLS IV plant water use classification for Gossypium harknessii, 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