The 2010 ASHS Annual Conference

There is increased interest in using native plant alternatives to invasive species for landscaping. While some native plants are commonly used, others with ornamental potential have yet to be developed. Comptonia peregrina L. (Sweetfern) exhibits wide adaptability in natural settings making it a prime candidate for use as a native landscape plant alternative for difficult sites. Research to optimize C. peregrina propagation by rhizome cuttings was conducted. Dormant rhizomes were cut into 5 cm pieces and planted in four different propagation mediums (MetroMix 510 growing medium, perlite, sand, vermiculite; n=32) in 5 cm × 5 cm × 7.6 cm containers. Containers were maintained in a dark cooler at 5 °C for 90 days before being moved into a warm greenhouse with set points of 23 °C day and 16 °C night for forcing. Cuttings were irrigated as needed and provided soluble 20-10-20 fertilizer at 200 ppm every seven days. Cuttings grown in vermiculite had 100% survival, while cuttings in MetroMix 510, perlite and sand had 81%, 81% and 6% survival, respectively. Cuttings in vermiculite produced the greatest number of shoots per pot (4.2) and total shoot length per pot (14.8 cm), but were not statistically different from the MetroMix 510 cuttings. Young plants derived from rhizome cuttings were transplanted into quart containers using a 4:2:1 bark: peat: sand growing medium and topdressed with 17-6-10, 8-9 month formulation controlled release fertilizer. After 60 days, plants were transplanted by placing two quart-container plants into a two-gallon container using the same 4:2:1 growing medium. Sixty days of additional growth in two-gallon containers produced full, well-established plants going into dormancy. This study demonstrates that full-grown two-gallon containers of C. peregrina can be produced in a single growing season from rhizome cuttings.