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Protocol Information

Jennifer Kleffner
Former Nursery Director
Lower Colorado River Prop. Specialist
PO Box 666
Bayfield, Colorado 81122
970/884/8191
jkleffner@hotmail.com


Family Scientific Name: Fabaceae
Family Common Name: Pea
Scientific Name: Olneya tesota Gray
Common Name: Desert Ironwood
General Distribution: Arid areas of Southern California and Arizona
Propagation Goal: Plants
Propagation Method: Seed
Product Type: Container (plug)
Stock Type: 1, 5 and 15 gallon pots
Target Specifications: For one gallon pots, height of 12 to 18 inches. Larger for larger containers.
Propagule Collection: Different trees will flower more or less each year depending upon rainfall in immediate area. Watch for heavily blooming trees in May, and return to collect seed later. Collect seed from mid June to mid July, as soon as seed pod and seed are dry but before it falls to the ground, to avoid insect infestation. If collected early, shelled and placed in airtight storage, insecticide is not necessary.
Propagule Processing: We store seed in surplus military ammunition cans, which are air and water tight when sealed. Seed is easily shelled by hand. As the seeds are collected during the heat of the summer (110 + degrees), retained moisture in the seeds is not an issue. By the time they are shelled, they are thoroughly dry. Cans are kept at outside ambient temperature in a storage shed.
Pre-Planting Treatments: Desert Ironwood is one of the few desert legumes who's seed does not need scarification. Simply soak seed in water for 24 hours before planting.
Growing Area Preparation/
Annual Practices for Perennial Crops:

All plants in our nursery are grown outside under 68% shade cloth or in full sun. (Plants grown under shade will be more leggy, but soil temperatures will be lower during the summer heat. Its a trade off.) Therefore, outside temperature dictates when to plant. Pots are the typical 7 in diameter x 7 in high black plastic pots such as the ones made by Nursery Supply. However, we reuse and buy back pots, so they are often a mix of slightly different sizes, styles and brands. No additional cleaning is done. Soil mixture is approximately 50% local soil (sand) and 50% inexpensive wood mulch (mostly to lighten up the pots for shipping)
Establishment Phase: After soaking seeds for 24 hours seed should be obviously swelled. Do not bother planting seed that does not swell, or seed that floats (usually indicating an insect infestation). Germination is non-existent unless the soil has thoroughly warmed (temperatures reach the 90's, normally in April). Seeds should be planted at a depth of about twice the seed diameter, one to two seeds per pot. Most germination should occur within one week, and is usually close to 90%. Herbivery of seedlings is not a problem. These are very drought tolerant plants, so irrigation should keep pots moist, but never soggy
Length of Establishment Phase: One month
Active Growth Phase: Thin to one plant per pot when trees are finger length high. Plants are actively growing from May through September, the hottest months. If transplanting to a larger pot, do it during this time. Prune off dead twigs in winter. Plants have long tap root and resent being confined. They often grow quite slowly in pots. However, I have seen them double in size in one growing season once planted and given adequate water.
Length of Active Growth Phase: May through September
Hardening Phase: After one year of growth, ie. April to April, either outplant or pot up trees. Plants have a deep taproot, and will be stunted if left in too small of a pot. Stunting can also occur if the soil temperature is excessive (not hard to do with black pots in full sun with 110+ ambient temperatures). Any transplanting needs to occur during the active growth period for success.
Length of Hardening Phase: None
Harvesting, Storage and Shipping: Plants are shipped via truck during the summer months. This is also an occasional landscape plant in SW Arizona, so some plants are potted up to larger sizes for retail sale. We recommend our retail customers plant these trees in May for best results.
Length of Storage: None
Outplanting performance on typical sites: Occasionally used as a revegetation plant in desert washes. Very drought tolerant, and considered a nurse tree for many many species. Information on survival, except as noted above, is not known. Planting in May with some supplemental water until established is recommended.
Other Comments: Desert Ironwood has the second hardest wood in the world. It is a very long lived tree (400 + years) and is considered the nursery plant of the desert. Over 175 other species of plant have been documented growing under Desert Ironwood, including Saguaro cactus. Ironwood forests are currently being lost on both sides of the US/Mexico border from urban sprawl, harvesting to make "mesquite" charcoal, and the now factory produced Mexican ironwood carvings.
References: Thanks to the Desert Legume Program (DELEP) sponsored by Boyce Thompson Southwestern Arboretum and the University of Arizona Tucson for helpful information on Desert Ironwood. Also refer to the Ironwood Alliance for more information on Ironwood forest destruction.

Citation:
Kleffner, Jennifer 2001. Propagation protocol for production of container Olneya tesota Gray plants (1, 5 and 15 gallon pots); Lower Colorado River Prop. Specialist, Bayfield, Colorado. In: Native Plant Network. URL: http://www.nativeplantnetwork.org (accessed 19 April 2014). Moscow (ID): University of Idaho, College of Natural Resources, Forest Research Nursery.