Joshua Tree (Yucca brevifolia)

How much light does a Joshua Tree need?

Full sun is where this tree belongs outdoors. No other light level is recorded for this species, and full sun is the preferred one. Utah State University Extension describes the tree as shade intolerant. Choose a spot where it will not stand in shade. No cited source gives a number of sun hours for it.

• Light: Full sun¹

How often to water a Joshua Tree

Its water need is recorded as dry, at both the low end and the high end of the range. Drought tolerance is rated high by Utah State University Extension. Its soil drainage is recorded as well drained. No cited source gives a watering schedule or an amount for this species.

• Water: Dry¹

Best soil for a Joshua Tree

Well drained soil is the one drainage type recorded for Joshua tree. The Lady Bird Johnson Wildflower Center advises transplanting into a well drained soil. The same records list its water need as dry. No cited source gives a pH range for this species, so soil pH is not documented here. Soil texture and amendments are not documented either.

• Soil drainage: Well drained²

Hardiness and temperature

USDA hardiness zones 7a to 10b are recorded for Joshua tree. Utah State University Extension words this as supposedly zones 7 to 10, which is a hedge. Check your own USDA zone against that range before you plant. No cited source records a minimum temperature for it. Humidity is not documented either.

• Hardiness: Zones 7a–10b¹

How to plant a Joshua Tree

Check that your USDA hardiness zone falls between 7a and 10b before you plant a Joshua tree. Pick a spot in full sun with well drained soil. The tree is often shrubby but can reach 20 ft (6.1 m) tall, with a trunk up to 24 in (61 cm) across. Growth is slow, with unbranched seedlings averaging 3 in (7.6 cm) a year for their first 10 years.

• Hardiness: Zones 7a–10b¹

Winter care

Winter limits are only partly documented for Joshua tree. It is recorded as hardy in USDA zones 7a to 10b. If your winters fall outside zones 7a to 10b, your site lies outside its recorded range. No cited source gives a minimum temperature, frost protection or winter watering advice. Its water need is recorded as dry.

• Hardiness: Zones 7a–10b¹

How to propagate a Joshua Tree

You can propagate Joshua tree by seed, stem cuttings and offsets. The Lady Bird Johnson Wildflower Center says yuccas can be grown from stem cuttings, or by digging offsets from the side of established plants. The USDA Forest Service says Joshua tree reproduces sexually through seed production. No cited source gives germination times, rooting times or a growing medium for any of these methods.

• Propagation: Seed, stem cuttings and offsets^2,3

Common problems

Yucca weevils, mealybugs and scales are the common pests recorded for Joshua tree. The diseases recorded are damping off, leaf spot and phytophthora root rot. The UC Statewide Integrated Pest Management Program lists agave and yucca weevils, and phytophthora root and crown rot. No cited source gives treatments or signs of these problems here.

• Common pests: yucca weevils, mealybugs and scales⁴
• Common diseases: damping off, leaf spot and phytophthora root rot⁵

Questions and answers

Does Joshua tree need full sun?

Joshua tree is recorded for full sun, and it is described as shade intolerant. Full sun is the only light level listed for it. No cited source gives a number of sun hours.

Is Joshua tree toxic to cats and dogs?

The ASPCA lists Joshua tree as toxic to both cats and dogs. Pet Poison Helpline describes mild vomiting and diarrhea as the typical effect in both animals, with possible pupil dilation.

How fast does Joshua tree grow?

Joshua tree is a slow grower. The USDA Forest Service reports that unbranched seedlings grew about 3 in (7.6 cm) each year over the first decade. Utah State University Extension says the tree can reach 20 ft (6.1 m).