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Loasaceae (Petalonyx)



Petalonyx (thurberi)


Loasaceae

Blazing Star Family


Petalonyx

thurberi



Gray











Sandpaper Plant

PETTHU

Joshua Tree National Monument, California

Petalonyx thurberi is found in dry sandy or gravely places in the Mojave and Colorado deserts from Inyo County, California to Nevada, Arizona and Lower 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 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.Inferred seed dormancy is physical dormancy.

Seeds are scarified with sandpaper and soaked in water overnight. Seeds are sown in open flats using a fine growing medium of 2 parts sand and 1 part mulch.(v:v). Germination %: 64%

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.




Graham, Jean. 2003. Propagation protocol for production of Container (plug) Petalonyx thurberi Gray 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 2024/03/29). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.