Answer: Since most roses are reproduced by budding, grafting or cutting rather than by seed, it may be hard to find seeds short of collecting your own. You might try contacting companies who specialize in growing roses such as Hardy Roses for the North, 607-442-8442, Heritage Rosarium, 301-774-2806 or Roses of Yesterday and Today, 408-724-3537. Otherwise, you might try collecting your own if you can find a source. Be aware, however, that if you collect your own seed from a white rose bush, the seeds may not produce white rose bushes since the seeds are open pollinated and may have genes from roses of other colors.
The seed pods on roses are called hips which hold the seeds. Rose seeds need a period of cold stratification before they will germinate, so you'll need to store them cold for three or four months prior to planting them. (Your refrigerator should do nicely.) Plant them as you would any other seeds in moistened soil mix, cover with clear plastic and set in a bright location away from direct sun.
You might also consider trying to grow plants for your experiment that don't take as long to mature, such as a perennial flower or an annual flower. Good luck!
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