Fabaceae (Senna)
Senna (armata)
Fabaceae
Pea Family
Senna
armata
(S. Wats.) Irwin & Barneby
Cassia
armata
S. Wats.
Desert Senna
SENARM
Joshua Tree National Monument, California
Senna armata is found below 3,700 ft elevation in sandy washes and open places in the Colroado and Mojave deserts in Nevada, Arizona and Southern California.
plants
seed
Container (plug)
2 Gallon PVC Pipe containers
12 Months
Height: N/A
Caliper: N/A
Root System: Firm Root Plug in container.
Seeds are hand collected in when pods have matured and begin to split open.
Seeds are allowed to dry for 4 to 6 weeks in paper bags in a warm, dry room. After seeds have been cleaned, they are stored under refrigeration in air tight containers at 7C.
Seeds are soaked for 45 to 60 minutes in a 50:50 (v:v) bleach and water solution. Seeds are soaked for 12 to 24 hrs in water prior to sowing.Seeds are sown in open flats using a growing medium of 2 parts sand, 1 part mulch and 2 parts perlite (v:v:v). Germination %: 50%
The Joshua Tree Native Plant Nursery is located in the Mojave Desert of southern California and has an average of 250 frost free days per year and annual rainfall of 5 to 10 cm (2 to 4 in.)
The facility is comprised of two greenhouses, shade structures, mist propagation beds and an outdoor growing compound. All propagation environments are utilized at different stages of seedling growth to provide for the variance in temperature and shading requirements during the growing season. We irrigate all containers with an automated drip irrigation system.
Seedlings are germinated during winter months in a small greenhouse were they remain for 4 weeks. Flats and containers are watered with a drip irrigation system. After seedlings are well established and have at least 2 true leaves, they are transplanted into newspaper cylinders wrapped with polyvinyl food wrap. The newspaper container is 29 cm (11.5 in) tall and 7.5 cm (3 in) in diameter. The newspaper pots are filled with a growing medium of 2:1:1 (v:v:v) sand, mulch, and perlite.
4 weeks
Seedlings are ready for transplanting into larger containers at 8 to 12 weeks. The entire newspaper pot minus the plastic wrap is transplanted into the PVC tall containers using the same medium described for the newspaper containers. Osmocote time release fertilizer (9 mo release rate) (13 N:13P2O5:13K2O) is incorporated into the medium at the approximate rate of 22 g per 6l ( 2 gal) PVC containers.
PVC containers are 37.5 cm tall(15 in) and are 15 cm (6 in)in diameter.
Following transplanting, seedlings are moved to a larger greenhouse with more temperature variance where they remain for another 4 weeks.
Approximately 4 weeks old after transplanting, they are moved to the open growing compound that is covered with a 55% shadecloth during the summer months. During the months of intense summer heat, containers are irrigated by an automated drip system every other day with occasional deep irrigation to leach out accumulated salts.
9 months
Irrigation frequency and duration is gradually reduced for 4 to 8 weeks prior to out-planting. The shadecloth is removed from the open growing compound in October when daytime temperatures begin to cool. Nursery stock is top pruned at this stage.
2 months
Containerized seedlings are over wintered directly in the open growing compound.
Variable; depends on out planting date.
This species can be directly sown to PVC containers to save time.
Graham, Jean. 2003. Propagation protocol for production of Container (plug) Senna armata (S. Wats.) Irwin & Barneby plants 2 Gallon PVC Pipe containers; USDI NPS - Joshua Tree National Park Native Plant Nursery Twentynine Palms, California. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2025/05/19). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.
