ALTERING TAPROOT ARCHITECTURE OF BLACK TUPELO (NYSSA SYLVATICA) TO A MORE FIBROUS ROOT SYSTEM

The demand for native plants in the urban landscape continues to increase. Traditional plant production methods in nurseries have had limited success in producing saleable plants from some of our native trees. One of the major difficulties relates to species that produce a taproot. I investigated alternate container production methods in a tree native to Illinois with multiple seasons of interest, the black tupelo (Nyssa sylvatica). Black tupelo is rarely found in the urban landscape because of a coarse root system rendering it difficult to transplant. Three existing root promotion techniques, air-root pruning, manual root pruning or auxin (K-IBA) dips, were used on container grown young seedlings and two-year-old transplanted liners. My objective was to alter taproot architecture of black tupelo and promote a more fibrous root system to alleviate transplant shock and facilitate field establishment. Results showed that superior root systems were produced using several air-root pruning containers that are also more economical than similar standard containers. Higher concentrations of auxin resulted in an increase in all plant parts measured, with an increase in survival after transplanting. Manual root pruning produced only minor benefit.