Last week I worked the TNSY booth at a seed swap sponsored by the Johnson City TN Parks Department. A woman presented me with an interesting question. She said she owns an abandoned farm field next to her house, and she wanted to know how to add native wildflowers without doing any removal of the existing grasses and weeds. It is an intriguing question and I am sure not an uncommon one. I told her to start out by purchasing a large quantity of seeds of aggressive plants that germinate easily from seed and can hold their own against existing weeds once they are up. I pointed out that there are quite a few that are $10 or less per ounce, and she could do it without spending lots of money. In a short time, she would know whether it was going to work. Otherwise she should look into purchasing plugs of aggressive plants.
I have never tried to do this actual task although I have lots of experience with aggressive plant species and some experience with seeding over established plantings. I thought this is a perfect opportunity to use the TNSY native plant blog to collect feedback from people who have tried to do this and learn what works and what doesn’t. Maybe she will even see this blog and get a more complete answer to her question. In the meantime, it is a great chance for all of us to learn more.
After thinking about the problem, I would expand my original suggestion as follows. First do a soil test and check soil type and moisture level in order to better match plants to the site. Second, mow the field area in fall, if you can, and broadcast the seed in early December. Third, think about how much seed you want to use per foot. Do at least the recommended rate for your site which is probably at least 100 seeds per square foot. You may want to even double the recommended rate.
I would recommend purchasing seed by the ounce of the following species based on a combination of two or more factors — ease of germination, aggressiveness once established, and cost (and, of course, always a good pollinator plant):
Canada Milk Vetch — Astragalus canadensis 17,000 seeds for $8
Partridge Pea — Chamaecrista fasciculata 2,700 seeds for $3 (an annual but a great spreader)
Purple Coneflower — Echinacea purpurea 6,600 seeds for $3
Maximilian’s Sunflower — Heliantus maximiliani 13,000 seeds for $4
Early Sunflower — Heliopsis helianthoides 6,300 seeds for $4
Wild Bergamont — Monarda fistulosa 35,500 seeds (half oz) for $9.75
Smooth Penstemon — Penstemon digitalis 130,000 seeds for $15
Yellow Coneflower — Ratibida pinnata 30,000 seeds for $10
Black-eyed Susan — Rudbeckia hirta 92,000 seeds for $3
Brown-eyed Susan –Rudbeckia triloba 34,000 seeds for $6
Sweet Black-eyed Susan — Rudbeckia subtomentosa 43,000 seeds for $12
Cup Plant — Silphium perfoliatum — 1,400 seeds for $15
Tall Ironweed – Vernonia gigantea — 28,000 seeds for $10
My hypothetical list would give you almost half a million seeds for $103. I used current prices in my favorite resource, the Prairie Moon Nursery catalog, to create this list.
Please add your ideas—modify this strategy or add to it; modify this possible list of plants by removing or adding to it—all based on your experiences!!