Other perennials decline in vigor if not divided at the appropriate time. One of the easiest ways to propagate a prized perennial is to divide the plant into two or more smaller plants. The best time to divide perennials varies with the different plant species. The appropriate time to divide widely grown perennials is presented below. However, butterfly weed is easily propagated by seeds.
Division is difficult, carefully divide in late summer.
Divide in spring. Plants can be started from seeds. Divide every 2 or 3 years in spring. Divide plants every 2 or 3 years in spring. Ornamental Grasses the best time to divide ornamental grasses is spring.