Spacing: 8-10 ft. (2.4-3 m) 10-12 ft. (3-3.6 m) 12-15 ft. (3.6-4.7 m) 15-20 ft. (4.7-6 m)
Hardiness: USDA Zone 6a: to -23.3 °C (-10 °F) USDA Zone 6b: to -20.5 °C (-5 °F) USDA Zone 7a: to -17.7 °C (0 °F) USDA Zone 7b: to -14.9 °C (5 °F) USDA Zone 8a: to -12.2 °C (10 °F) USDA Zone 8b: to -9.4 °C (15 °F) USDA Zone 9a: to -6.6 °C (20 °F) USDA Zone 9b: to -3.8 °C (25 °F) USDA Zone 10a: to -1.1 °C (30 °F) USDA Zone 10b: to 1.7 °C (35 °F)
Sun Exposure: Full Sun
Danger: Plant has spines or sharp edges; use extreme caution when handling
Bloom Color: White/Near White
Bloom Time: Late Winter/Early Spring
Other details: Drought-tolerant; suitable for xeriscaping
Soil pH requirements: 6.1 to 6.5 (mildly acidic) 6.6 to 7.5 (neutral) 7.6 to 7.8 (mildly alkaline)
Patent Information: Non-patented
Propagation Methods: By dividing rhizomes, tubers, corms or bulbs (including offsets) From seed; winter sow in vented containers, coldframe or unheated greenhouse From seed; sow indoors before last frost
Seed Collecting: Allow pods to dry on plant; break open to collect seeds
I have a Joshua tree that I raised from seed that is about 14 years old. I keep it in a tall pot (3") as I live in western Oregon and am afraid it would be too wet if planted in the silty loam soil with a high water table in the wet season. I also keep it under the eave of the house on the east side so that it doesn't get a lot of rain falling into the pot. It is about 18" tall. It has damaged me and my wife with the sharp leaves many times!
Joshua Trees do great in Treasure Valley, Idaho (Boise area), 2500' elevation, high desert (10 or 11 inches precip.), variety of soils, so planting area must be prepared suitably. Hot summer days and evenings til midnite or so, several days in winter that may be connected or random down to zero or -5, but typical Dec or Jan night is 20 degrees or warmer, daytime 25-35. I'vd been here since '93; stories tell of some colder winters, but there are some Joshuas here 10' in height.
Trachycarpus takil (Kumayon (sp?) palm) has been tried here over the past 5 years (cold hardy to -5) but do poorly; the right index of factors apparently not here.
On Mar 8, 2008, peachespickett from Huntington, AR wrote:
Spent a lot of time with the Joshua Trees living outside Death Valley in Nevada for some years. Now I have one growing in one of my xeriscape beds here in Arkansas and it's actually surviving, wet and cold haven't bothered it, though it is planted in a 50/50 gravel/sand mix on a southwest wall. Grew from seed years ago, now about a foot tall. You can grow almost anything from the desert anywhere, provided it's hardy enough, you give it amazing drainage and plenty of sun. Also have sagebrush, pinyons, and a hundred other things that don't grow naturally within a thousand miles of here.
The Joshua tree is a large, erect, evergreen, arborescent monocot. It is usually single-stemmed, but trees with two or three stems will sometimes occur. The Joshua tree is the largest nonriparian plant of the Mojave desert, they can reach heights of 16 to 49 feet, and the trunks can grow 2 to 4 feet in diameter. Erratic branching will generally begin at 3 to 10 feet above the ground. Flowering of the Joshua tree requires a year with sufficient precipitation, if enough precipitation occurs they will generally begin to bloom in early spring with 18 inch clusters of 1.5 inch yellowish, bell-shaped flowers. This species grows from southern California, Mexico, and western Arizona eastward into southern Nevada and southwestern Utah.
This plant has been said to grow in the following regions:
Phoenix, Arizona Scottsdale, Arizona Tucson, Arizona Yucca, Arizona Acton, California El Cajon, California Folsom, California Mountain View Acres, California San Diego, California Twentynine Palms Base, California Nampa, Idaho Salineno, Texas Magna, Utah Orem, Utah