The last few days have seen the end of summer and the shortening days of autumn are soon upon us. The flowering parts of many plants grow fat with seed and, before the birds take all, we should harvest. I especially like to harvest the seeds of tall annual and perennial flowers that are never found as transplants sold in spring. I routinly collect Cosmos, Nigella, Larkspur, Calendula, marigold and Verbena bonariensis to dry and save for next year. Basically I snip off the seed heads just as they are maturing and stick them upside down in a brown paper bag to dry. Lunch bags work well for small seed heads while larger grocery bags are best for long stemmed flowers such as larkspur and digitalis. The trick is to get the ripening seedheads before they rupture and drop their seeds. I stick the seedheads upisde down in paper bags and leave them in the garage to dry for a few weeks. The seeds will drop to the bottom of the bag where they can be collected and stored over winter in ziploc bags. Truth be known, more often than not, I let the seedheads dry overwinter in the bags and come spring simply plant the whole seedhead without ever separating the seed from the plant. Just bury a dried zinnia or calendula flower/seedhead in the soil in spring, or tear the flower apart and scatter. I also like to ‘snow scatter’ which is to scatter the seeds of early annuals like snapdragon, calendula and viola over the top of snow. The seeds will freeze and thaw and loosen up while getting watered by the snow. The snow melt will carry them down where they will settle gently and firmly into the soil to germinate at exactly the right time.
Verbena bonariensis, sunflowers and Verbascum are easy to collect from seed
Seed sowing is really the best way to grow all those tall annuals we love and that can fill a space with massive color and wildlife food – cosmos, varbascum, sunflowers, verbena, calendula, nigella, chamomile. Some of these return to be rather weedy but worth it!