PROJECT LEADER(S): Thomas G. Ranney
Propagation studies were conducted to optimize and refine production protocols. Summer cuttings (terminal and sub-terminal) were evaluated for rooting potential following treatment with a range of auxin concentrations. Production demonstrations were established and displayed at tours and field days. A stock block of 'Summer Cascade' trees was established to provide North Carolina growers with a source of propagation material. Plants were propagated and distributed to growers. On-farm trials were established with growers across the State.
Propagation. Propagation studies found that 'Summer Cascade' can be easily produced by summer stem cuttings. Terminal cuttings generally rooted at higher percentages than sub-terminal cuttings (Fig. 1). Rooting increased with application of auxin, but there was little difference in percent rooting between treatments of 2,000 to 8,000 ppm IBA. Root number increased slightly with increasing auxin concentration (Fig. 2). In general, terminal softwood cuttings taken in summer (July and August) and treated with a basal dip of indole butyric acid at 2,000 to 8,000 ppm resulted in high rooting percentages (>95%) and heavy root systems (>13 roots per cutting).
Figure 1. Rooting percentage of 'Summer Cascade' river birch as a function of auxin concentration. Symbols are means of 9 samples with 6 subsamples each. Bars are equal to 1 SEM.
Demonstrations and Trials. Container and field production demonstrations have been established at the Mountain Horticultural Crops Research Station. These demonstrations were included in the Nursery and Specialty Crops Field Day held in Sept. 2002 and included in over 20 tours for nursery growers. Presentations were also made at the Southern Nursery Association Research Conference, North Carolina Green and Grow'n Show, Southern Region International Plant Propagators Meeting, and numerous county extension programs. Plants are on display at the North Carolina Arboretum and the J.C. Raulston Arboretum. On-farm trials have been established with the following growers and most are now producing this plant:
Appalachian Trees, P.O. Box 92, Glendale Springs, NC 28629, 336-982-2377 email@example.com
Beverly Hill Garden and Nursery, 288 Halls Chapel Rd., Burnsville, NC 28714, 828-675-4756, firstname.lastname@example.org
Clark's Liner Farm, 4156 Blue Creek Lane, Oxford, NC 27565, 919-692-1020 email@example.com
Hawksridge Farms, P.O. Box 3349, Hickory, NC 28603. 828-294-2081 firstname.lastname@example.org
Highland Creek Nursery, 269 Drake Farm Road, Fletcher, NC 28732, 828-687-0996 email@example.com
Johnson Nursery Corp., 985 Johnson Nursery Rd., Willard, NC 28478, 910-285-7861 firstname.lastname@example.org
Meadowbrook Nursery, 2055 Polly Spout Rd., Marion, NC 28752, 828-697-8463 email@example.com
Tarheel Native Trees, 4339 Peele Rd., Clayton, NC 27520, 919-553-5927 firstname.lastname@example.org
Stock block. A stock block of 100 'Summer Cascade' trees has been established at the Mountain Horticultural Crops Research Station. These plants will be available as a source for propagation material for North Carolina nurseries.
Distribution of Stock Plants. Over 700 plants were propagated and distributed for stock plants and for evaluation. In addition to distributions to NC growers, plants have been sent to institutions (Universities, Arboreta, etc.) around the country for promotion and evaluations.
All signs indicate that 'Summer Cascade' is going to be an extremely successful introduction that will yield North Carolina growers substantial returns. The biggest challenge in the next few years will be meeting demand. A photograph of 'Summer Cascade' that was published in Nursery Manager Pro magazine resulted in over 100 inquires from nurseries in the US and abroad looking for sources of plants. National sales could easily reach 100,000 to 200,000 units per year. At a wholesale value of $25 per tree, annual sales could exceed $5,000,000. Retail value would be twice that amount. There are currently eight nurseries in North Carolina propagating 'Summer Cascade' for resale to field and container nurseries. As plants become available, we expect hundreds of nurseries will be producing this plant. Efforts are also underway to establish markets in Europe, Japan, Australia, and New Zealand.
Updated May 2003