Roof Flower Mix This wildflower seed mix is designed for roofs and slopes, but is also suitable for flower beds and meadows. The mixture consists of 25 varieties of annual and perennial flower seeds. Since these flowers do not bloom at the same time, you can enjoy them throughout the season. It is recommended to sow the seeds in early spring. These flowers can withstand short-term droughts. You will get more flowers next year if you let the plants flower and spread their seeds.