By Cindy Gilberg
The seed is hope; the flower is joy.
– Author Unknown
The cooler days of autumn are incredible for taking a walk through the garden or the prairies and woodlands at Shaw Nature Reserve. At this time of year the last bits of color fade to reveal the ripening seed heads of late-summer and fall-blooming perennials such as aster, goldenrod and late blazing star. Native grasses are full with fat seeds, causing them to bend over and sway in the wind. Seeds, those marvelous little parcels of hope for next year’s bounty in the garden, are everywhere. Goldfinches and other birds are taking advantage of this important fall and winter source of food.
Why bother to collect seeds? One major reason is the satisfaction of growing your own plants to expand your garden. Because many native plants, such as butterfly weed, have deep tap roots, it is much easier to start new plants from seed than to try to dig and move or divide them. Besides, it is illegal to dig plants in the wild. Another wonderful reason is to share them with other native plant enthusiasts.
Getting to know your plants’ bloom time will give you an indication of when to begin collecting seeds. The early- to mid-spring-blooming natives form their seeds beginning in late April through May. And so, in a regular progression, other later-blooming plants begin to form ripe seed, typically within four to six weeks after their flowers have faded. Take the time to be observant and take notes so that next year you will have a “heads up” as to when to look for your favorite seeds.
Don’t be impatient – be sure to wait and collect seed that is ripe. Unripe, green seeds will not ripen on their own after being cut from the plant. To determine ripeness note the color of the seed since immature seed heads are very green or there is still color in their flower petals. Wait until petals fade completely and the seeds turn tan or brown. September through November is when plants such as goldenrod, aster, ironweed and blazing star turn a dark russet color and begin to appear “fluffy,” indicating that they are ripe and ready to fly away on the first winter wind.
Collect seed when the weather is dry. Avoid the morning dew, waiting instead for mid-morning or later after the sun has begun to warm and dry the seed heads. If seed heads are moist, you run the risk of spoilage due to mold. Seed heads can be cut into paper bags or placed into cardboard flats to insure that sufficient drying takes place. Once dry, the seed separates easily from the plant tops, capsules or pods depending on what you collect. Shake the bag and separate the seed from the chaff. A sieve or screen is quite useful at this point. Once the seed is fairly clean, it should be placed in a mixture of moistened potting soil and sand (50/50) in a ziplock. Mark the name of the plant and the date you collected it on the bag, then store it in the refrigerator or other cold place for three months. This process, known as stratification, mimics the natural cycle of winter. In the spring, the seeds can be sown either into pots or directly in your garden, ready for the new year.
An option would be to sow the clean, dry seed directly into the garden in late November and December, thus freeing up sometimes-valuable space in the refrigerator. The drawback to this method is that you might be providing a wonderful meal for foraging birds and rodents in the winter and it is sometimes difficult to identify seedlings in the spring. A wonderful little book that can help you with identification is Seedling ID Guide for Native Prairie Plants. It is available at the Visitors’ Center at Shaw Nature Reserve and at Missouri Department of Conservation – Powder Valley in Kirkwood as well as on their website, MDC Nature Shop. So far there is not a printed book on woodland seedlings or others you may collect so it is a great idea to photograph those seedlings as they come up in pots and keep them for future reference.
Remember to only harvest what you need – don’t be greedy. Unless you have an acre or more to seed, try to leave a lot of plant tops with seeds to provide food for overwintering birds and small mammals. Don’t cut the dying foliage to the ground since it is a source of shelter small animals. A close look will reveal chrysalis and cuccoons, egg cases of mantids and other overwintering insects.
If you feel there is enough for everyone, note that the dried seed heads are also quite fascinating subjects for dried arrangements.
Keep seed collecting in mind next spring as you see other plants you want to add to your garden. Starting in late April-May, woodland wildflowers such as wild geranium, bellflower and sweet william begin to ripen. Go ahead and collect, clean and store those seeds in the refrigerator. Keep them there until late November for sowing outside. Or leave the seeds in your refrigerator through winter and sow in early spring for another year’s bounty.
Cindy Gilberg, horticulturist and Missouri native, founded and ran the garden center at Gilberg Perennial Farms with her husband Doug for 28 years, also teaching classes and workshops on gardening and garden design. She now focuses on garden design, consulting and teaching, and also works part-time in the Whitmire Wildflower Garden at Shaw Nature Reserve, emphasizing the use of native plants in home landscaping.