California Desert Thorn Plant Care
Lycium californicum Nutt. ex A.Gray
Updated · Sources · How we source care data
Lycium californicum is a spreading shrub in the nightshade family known by the common names California boxthorn and California desert-thorn.
Every 7–14 days
Full sun to partial shade
50–85°F
40–70%
At a glance
How do you care for California Desert Thorn?
Plant California Desert Thorn in full sun to partial shade (USDA zones 12a) and water a young shrub every 7–14 days until it is established. It tolerates temperatures of 50–85°F (10–29°C). Fertilize it every 6 months during the growing season.
What Is the California Desert Thorn?
California Desert Thorn (Lycium californicum) belongs to the Solanaceae family within the Lycium genus. California Desert Thorn is also known as Desert Thorn, California Boxthorn.
California Desert Thorn displays an upright, spreading shrub growth habit, reaching up to 4 ft tall with a spread of approximately 6 ft. California Desert Thorn produces small, tubular purple or white flowers.
Leaf size: approximately 2 inches.
How Often Should You Water a California Desert Thorn?
Water a young or newly planted California Desert Thorn every 7–14 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established shrubs mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.
Watering Frequency
Every 7–14 days
Until established; then in dry spells
What Light Does the California Desert Thorn Need?
California Desert Thorn thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the California Desert Thorn Prefer?
Lycium californicum tolerates temperatures of 50–85°F. California Desert Thorn prefers humidity levels of 40–70%.
Temperature
50–85°F
Humidity
40–70%
What Soil Mix Works Best for a California Desert Thorn?
Well-draining sandy loam with added organic matter. Good drainage is essential for California Desert Thorn to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a California Desert Thorn?
Feed California Desert Thorn every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established shrubs in good soil often need little extra feeding, so let weak growth or pale foliage guide you.
Stop feeding by late summer so new growth can harden before winter.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
Where Should You Plant a California Desert Thorn?
Choose a spot with full sun to partial shade and well-draining sandy loam with added organic matter. Avoid low spots where water collects after rain.
California Desert Thorn is suited to USDA Zone 12a.
Plant container-grown or balled-and-burlapped shrubs in spring or early autumn, setting the root flare at soil level, and water well after planting.
How Far Apart Should You Plant a California Desert Thorn?
California Desert Thorn can spread to about 6 ft (1.8 m) and reach about 4 ft (1 m) tall. Space plants about 6 ft (1.8 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.
Planning a row or hedge? Try the plant spacing calculator.
How Do You Prune a California Desert Thorn?
Prune California Desert Thorn while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.
If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the shrub in one year.
How Do You Care for a California Desert Thorn in Winter?
California Desert Thorn is frost-tender (hardy to USDA zone 12). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.
How Do You Propagate a California Desert Thorn?
California Desert Thorn can be propagated through seeds, softwood cuttings. Similar propagation techniques also apply to african boxthorn plant care, which shares the same genus.
Is the California Desert Thorn Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list California Desert Thorn, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the California Desert Thorn?
California Desert Thorn is susceptible to aphids, spider mites, whiteflies. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the California Desert Thorn Need?
California Desert Thorn grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. In cooler regions, grow California Desert Thorn as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
California Desert Thorn is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Lycium genus — compare its care with other Lycium species on PlantoScan.
Lycium is part of the Solanaceae plant family — browse all Solanaceae genera and species.
California Desert Thorn thrives in bright light and direct sun — see other bright-light plants.
More Lycium Species
Other Lycium species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Lycium californicum Nutt. ex A.Gray, family Solanaceae (first published in Bot. California [W.H.Brewer] 1: 542. 1876.) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list California Desert Thorn, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
