#410 Care and Planting of Joshua Trees
Success with wild-collected plants
The Joshua Tree (Yucca brevifolia) is a distinctive Mojave Desert native which grows naturally in 3000-5000 foot elevations. Wild-collected specimens can be transplanted to landscapes under the following conditions:
• Collecting Specimens – Joshua Tree specimens cannot be collected from the wild without official permits from California, Nevada, Arizona or Utah. Some states, including Nevada, also require that tags be affixed to these trees in most situations. It is illegal to sell or purchase collected trees without these permits. The tags are designed to show tampering, and should be intact when you purchase the plant. Once planted, the tag can be removed. The tag or permit must be kept to prove that your tree was not illegally collected. Purchase plants from reputable dealers; be wary of pickup truck and street corner vendors.
• Preparations for Planting – Prior to planting, dust the roots with powdered sulfur or horticultural charcoal to prevent fungal diseases.
• When to Transplant – Joshua Trees should be transplanted from the wild during October through March. Plants dug during warmer weather generally have a poor transplant recovery rate. Specimens under four feet seem to transplant more easily.
- • Replant Joshua Trees in their permanent spot in the same season they were dug.
- • Specimens which aren’t planted immediately should be temporarily planted in dry sand, either upright or at an angle. Plants normally cannot be held successfully through summer in this way, so give them permanent homes as soon as possible.
• Soil Drainage – Excellent drainage is necessary. Joshua Trees do not grow at the bottoms of most valleys for this reason. Make sure that the new planting location either drains well naturally or is made to drain well by amending soil with sand and gravel. Creating raised soil mounds is another way to overcome caliche and heavy clay areas. A large hole is not necessary if the soil drains well naturally, but should be dug if heavy clay is encountered. Organic soil amendment is not necessary. Large rocks should be removed from the hole prior to planting.
• Testing for Drainage – The planting hole should be filled with water and allowed to drain before planting. Not only does this create a good environment for re-establishment, but it allows you to double-check the drainage. The hole should drain completely within 2-3 hours. Place tree in the hole and backfill with native or mineral-amended soil. Note the soil line on the trunk to determine correct planting depth; do not plant too deep. Create a volcano-like depression, known as a watering basin, in a 2-3 foot radius from the trunk. Water the plant thoroughly with a solution of Dr. Q’s® Plant Tonic and water.
• Planting Directional Orientation – Opinions vary on whether the tree must be replanted with the same directional orientation it had when originally dug, to prevent sunburn and growth distortion. Unless planting like this would create a serious problem, it is a practice which should be followed. Most commercially available trees have been clearly marked with the original direction of north.
• Guy-Wire “Staking” – Larger plants may require stabilization until they root firmly. Use guy-wires connected to stakes in the ground, attached to the trunk or limbs with an expandable, non-abrasive connector such as Black Spring Tree Tie or <em. Do not use a single stake which may blow over with the plant in a strong wind.
• Watering – To establish a Joshua Tree provide a minimum of 2 gallons water 1 to 2 times per week. Wet soil will cause mildew and root rot. Occasional over-the-top watering to simulate rainfall is also beneficial. A plant is said to be established after it resumes growth, usually by the next spring after planting. Established plants can subsist with watering every month during the summer. Plants will look better with a good watering every two weeks (less with good summer rains).
• Misting – Some experts recommend a light misting of the green tree heads every few days during the first summer, to prevent the tree from drying out. This treatment can be especially beneficial if a particularly hot and windy period follows transplanting.
• Fertilization – Many opinions are given regarding fertilization of Joshua Trees. Some fertilize with a mild fertilizer like Fish Emulsion once a year. Others say this tends to make spurts of growth which ruins the natural look of the plant. The Mojave Cactus Club recommends application of a mild, slightly acidic fertilizer in April and October. Whatever you decide, remember that Joshua Trees in the wild get no fertilizer. We feel that a schedule of regular feeding for cultivated specimens is not needed.
• Pests – With the exception of the Agave Weevil, the cultivated Joshua Tree is not plagued by significant pests or diseases once established. In the case of a noticeable change in appearance or growth after the establishment period, contact the local office of the State Department of Agriculture, your County Cooperative Extension or the nursery where you purchased your plant.