When To Plant

Wildflowers can be planted either in the early Spring, when most people are planting their garden or in the Fall (dormant seeding) when Mother Nature does her planting. For Spring planting, sow one month prior to the date of last hard freeze and gently water the area for the first month or so (unless Spring rains do it for you) to enhance germination. The freeze-thaw cycles help to break the dormancy of some species for better germination when the temperatures/light and moisture are correct.
For late Fall planting, simply scatter the seed on top of the soil and rake the seed into the soil when freezing nighttime temperatures are consistent, lightly mulch the area, water once to get good soil contact and forget. The seeds will remain dormant through the winter and germinate the following spring when the soil warms and the days are longer.
In temperate zones, sowing at other times of the year can be successful.  Plan to sow seeds for germination during the cool, moist time of year to allow the plants to become well established before the hot, dry season.
Once established, taking care of your wildflower garden is a must. This means you should evaluate the site once a year (usually late summer) and determine if your expectations are being met. You should understand the first year will produce a dazzling display probably not repeated in years to follow. This is true because the flush of annuals in the mix tends to initially dominate the perennials. Most perennials do not flower the first year, instead, they are expanding their deep root system to ensure longevity.