Evaluation of Two Perennials (Baptisia australis and Physostegia virginiana ‘Vivid') in Low-Input Nursery Production Systems

Pot-in-pot (PiP) production systems combined with drip irrigation have shown to be effective in increasing output, while reducing inputs in large container production of woody nursery plants.  However, published research examining small container PiP production is limited.  With PiP production as a possible risk management tool for weather extremes, this experiment was designed to evaluate how PiP production compares with above ground container production in a minimal input nursery production system. Two perennials, Baptisia australis and Physostegia virginiana ‘Vivid’, were evaluated in this experiment. The species were grown in 2 gallon containers in both production systems and subjected to low, mid, and high levels of nutrients and irrigation.  The high levels of nutrients and water were low by industry standards creating a stressed environment for the plants. The data collected at intervals during the growing season included; plant width (in two perpendicular directions), height, health rating, flowering, and mortality. Both species exhibited lower mortality and higher growth indices in the PiP system in comparison to the aboveground container production.  The PiP system provided greater frost protection after spring shoot emergence for fall-planted B. australis. Increasing nutrient levels also increased survivability and growth.  The varying irrigation regimes did not significantly affect survivability or growth of these two species.