Phlox Germination

Phlox blooms in different shapes, sizes and colors, depending on the species.

Phlox is a perennial flowering plant, adapted to growing in U.S. Department of Agriculture hardiness zones 3 to 9, depending on species. This North American native plant thrives in moist soil. Although many gardeners purchase small phlox starter plants from nurseries, it is possible to grow the plant from seed.

Pre-Treatment

Phlox seeds germinate more reliably when cold-moist stratified before planting. Place the seeds in a handful of barely moist sand or peat moss, seal in a plastic bag and refrigerate for four weeks.

Planting

Plant the seeds in a quality seed-starting mix six weeks before the outdoor temperature will remain 53 degrees Fahrenheit or warmer. They do not require light to germinate.

Timing

Even under the best of conditions, phlox seeds can exhibit erratic germination. After stratification, most seeds will germinate within seven to 10 days.

References

• Johns Hopkins University Project Muse: Improving Seed Germination of Native Perennial Phlox Longifolia
• "Perennial Reference Guide"; Karleen Shafer and Nicole Lloyd; 2007

Resources

• University of Minnesota Extension: Tall Garden Phlox for Minnesota Gardens