1. 1Department of Horticultural Science, University of Minnesota, 1970 Folwell Avenue, St Paul, MN 55108
2. 2Ohio State University Extension Clark County, 3130 East Main Street, Springfield, OH 45505
3. 3Department of Horticultural Science, North Carolina State University, 4415 Beryl Road, Raleigh, NC 37606
4. 4Department of Horticulture and L. Arch., Colorado State University, Campus Delivery 1173, Fort Collins, CO 80523
5. 5Department of Environmental Horticulture, University of Florida, 3205 College Avenue, Davie, FL 33314
6. 6Department of Horticultural Sciences, Texas A&M Agricultural Research and Extension Center, P.O. Box 200, Overton, TX 75684
7. 7Department of Plant and Soil Science, University of Vermont, 568 Westford Road, Milton, VT 05468
8. 8Department of Horticulture, Oregon State University, 4143 Ag Life Sciences Building, Corvallis, OR 97331
9. 9Horticulture Research, Longwood Gardens, 409 Conservatory Road, Kennett Square, PA 19348