My purple coneflower plants still have many seeds on the dead heads. Can I sprinkle them over pots of soil now and leave them outside? Or should I wait? Or should I don something indoors, which I would rather avoid. Thanks, Lydia
Thank you for contacting the Toronto Master Gardeners. Your purple coneflower plants (Echinacea purpurea) still have seeds on their seed heads that have remained over the winter. It is recommended that seed heads remain on the plants throughout the winter months to provide food for birds. You ask how you can use the remaining seeds to grow more plants.
Growing Echinacea purpurea from seed is relatively simple if the conditions allow the seeds to germinate. If one sprinkled the seeds over a section of ‘prepared soil’ outdoors (March/April), some might germinate this spring due to the moisture in the soil (which is still cold and partly frozen), and the continuing fluctuating temperatures that we are experiencing now. Some sources recommend cold-stratification for at least 4 weeks (keeping the seeds in a moist, cold condition). Others have had success without doing so (see: here.). If you have a small section in your garden that can be used, you could easily prepare the soil and ‘sprinkle’ the seeds now. Depending upon weather conditions for the next few weeks, it’s possible that they might germinate. However, if you seeded them in the soil in the Fall, the probability of germination would be higher.
If you prefer to use pots, the soil in the pots would need to remain cold and moist for at least for a few weeks after you planted the seeds–they might germinate as outdoor conditions gradually warm. However, you may be able to find some seeds on the ground around the seedheads now–they might have been subject to some stratification throughout the winter–they could be ‘planted’ in pots now as long as the outdoor temperatures continue to fluctuate. Scatter some into pots with cool moist soil; cover slightly with soil; leave them outdoors in a protected area while the air and soil temperatures gradually rise. Even in the best conditions, not all the seeds will germinate; nevertheless, it is certainly worth trying.
You are no doubt aware that Echinacea purpurea is considered a low-maintenance native plant– an attractive plant important for pollinators, supporting wildlife and maintaining biodiversity in our gardens. We trust that you will be successful with germinating some plants–keep in mind that it may take a couple years for them to develop blooms.