Preliminary Studies on Propagation of Osha

Osha ( Ligusticum porteri ) is a perennial plant native to the Rocky Mountain region of the United States and has been used as a medicinal herb to alleviate certain ailments caused by viruses, yeasts, and other microbes. It is generally harvested in the wild and is believed to be in danger of overharvest. The objectives of this study were to determine if osha could be grown successfully from seeds, seeds still attached to umbels, root cuttings, and/or vegetative crown cuttings. Seeds were harvested from the wild in Fall 2000. Roots were collected in May 2001. Seeds, either detached or attached to umbels, were given one of four treatments: 1) no stratification; 2) 6 weeks at 4.4 °C (40 °F); 3) 4 weeks each alternating 4.4 °C, then 12 hour 20.0 °C (68 °F) and 12 hours 30.0 °C (86 °F); or 4) 12 weeks at 4.4 °C. Roots were divided into crown cuttings, each containing a vegetative node, and were placed on a 21.1 °C (70 °F) mist propagation bench until rooted. Twelve weeks of stratification, whether seed was detached or attached to umbels, were beneficial for germination of osha seeds, but only gave about 11% emergence. Propagation from root cuttings was not successful. Propagation via vegetative crown cuttings was most successful, with 90% of cuttings rooting. Vegetative propagation of osha appears to be the most promising method, preferable over seed propagation.