Large scale wildflower projects need careful planning to help ensure success. The larger the project, the more elaborate the planting process will be and the more likely you will need volunteer help.
Start small when you plant a wildflower area. Larger plantings are expensive and require more labor during site preparation, planting and initial maintenance. Do not try to interfere with existing landscaped areas. If you do not have the time, money or machinery to properly establish and maintain a large tract, it is best to try a smaller, more manageable plot. You can expand plantings over time using techniques and species that are successful in the initial planting.
You will need to be organized to plant a big project. If you are using volunteers, be sure they receive reminders about planting dates, instructions on what to wear (comfortable outside work clothes) and what to bring (rakes, gloves, lunch, etc.). Try to find safety vests and "Work in Progress" signs to use in heavily trafficked areas.
We do not recommend planting commercial wildflower mixes. It is much better to prepare your own mix of the species you plan to plant. Consider plants well-suited to your particular site and plan for overlapping bloom times. Buy seeds from local seed sources.
One rule applies to all plantings, good seed-to-soil contact is essential for germination. You can use an agricultural grain drill, a cultipacker planter or a mechanical seeder to seed wildflowers into existing vegetation or into a clean bed.
Grain drills usually plant grass seeds, but you can use them to plant wildflower seeds. Grain drills cut furrows into the ground, dropping seeds into the furrows from seed boxes. Drills with more than one box can simultaneously plant different types of seeds (e.g., fluffy, large, or small) at the recommended rates for each. A chain or rubber tire behind the drill works the seeds into the soil. A grain drill is labor-efficient and provides an even seeding rate, but the seeds are distributed in rows, which may produce an undesirable effect. Cultipackers usually plant grasses, but the seed box can be set at a specified seeding rate to plant wildflowers and native grasses. A roller bar follows, packing the seeds into the soil.
An adjustable, hand-carried mechanical seeder is effective for many plant species, but some species have small seeds that are difficult to distribute evenly. Mixing small seeds with fine, damp sand before distribution prevents seeds from clumping. Hand-broadcasting is easy. For better seed distribution, mix the seeds with fine, damp sand, in a proportion of four parts sand to one part seed. Hand-sow seed into the prepared area, then rake or tamp seeds into the soil.
If tall weeds are shading your wildflower seedlings, mow above the seedlings several times the first year to help suppress annual weeds. A scythe or hand clipper will do the job if the mower blades can't be set high enough. Most weeds are annuals, so mowing them before the seeds set will destroy the crop. The exact time and height of mowing varies with each site and you might have to mow during the second and third years. In many cases, you can't avoid hand-weeding or sport herbicide applications, especially if aggressive species or perennial weeds are dominating the site. You might need to reseed or spot-transplant species to fill in bare spots or increase diversity, especially in the second or third year after seeding.
Delay mowing your wildflower area until at least half of the last blooming species have dropped seeds. Annual and biennial wildflowers must be allowed to reseed to produce a strong stand next year. Don't mow native grasses in late summer and early fall, during their elongation, flowering and seed-set periods. Never mow mid-to tall grasses below six inches.