Annuals are plants whose natural life cycle is one season long: they sprout, they bloom, they set seed, they die. Most annuals are propagated by seed.
Perennials, on the other hand, live for several to many years. As they grow, they produce larger and larger root systems, supporting larger and larger top growth.
As a result, propagation is often by root division, rather than by seed, although you can certainly grow perennials from seed too.
Are you confused yet?
What Are They Good For?
Perennials are great for estabishing some stability in a garden. You put in a few perennials, and the rest just falls into place around them. You know they’ll be there year to year. Some examples are: peonies, salvia, yarrow, coreopsis, daisies, echinacea, rudbeckia, asters, balloon flower, lupins and many more.
Most perennials bloom in late May and June. Some bloom in the Fall. No perennials bloom continuously throughout the summer. That’s what annuals are for.
Annuals are great for filling in between perennials, and for filling out the summer season with bloom. You can either start them from seed yourself (indoors or direct sow in the garden) or you can buy them from a good nursery.
For the most vigorous plants, direct sowing is probably the best bet. Some examples of colorful annuals are: coleus, petunias, calendula, marigold, pansies, godetia, african daisies, forgetmenots, morning glories and many more.
Most annuals start blooming in late May and early June, and continue blooming into Fall. Some will bloom until frost.