Metro-East Living

What’s the differences between flowering annuals and perennials?

Popular flowering annuals include petunias, marigolds, impatiens and zinnias.
Popular flowering annuals include petunias, marigolds, impatiens and zinnias.

Q: I would like to know what the differences are between flowering annuals and perennials.

N. E. of Belleville

A: Comparing flowering annuals versus perennials is similar to comparing apples to oranges. Each type of plant has its own characteristics and advantages.

Flowering annuals complete their life cycle in just one growing season. You plant a seed or seedling plant, and it flowers for a longer period of time and at the end it dies all in the same year. Annuals usually bloom from the spring until the autumn frost. They must be replanted every year, but they have a long period of producing showy flowers.

Popular flowering annuals include petunias, marigolds, impatiens, and zinnias which are commonly sold. There are others which are little more exotic such as spider flower (Cleome), Gazania, and Lisianthus. There are other annuals grown just for their attractive foliage, which include the brightly colored coleus, Joseph’s coat, and snow-on-the-mountain. There are some vegetables that are ornamental such as flowering cabbage.

Perennials grow for three or more years. But perennials tend to have a relative short period of blooming. Some perennials can rebloom for a second time later in the season. Usually most gardeners planting perennials use several different types so that there are always some flowers in bloom. You have to do a little homework with perennials to figure out a sequence of flower production. These can include from spring flowering bulbs, to peonies, daylilies, coreopsis, liatris, and garden mums. Some mail-order catalogs give drawings of perennial garden beds. Regular visits to the botanical garden can give you an idea of what the perennials look like at various times of the year.

Q: Every year we add new mulch to our garden beds to keep the weeds down. We use shredded bark mulch. This year we have found yellow and beige foam forming over the top of this mulch. Then it slowly dries up, changes color and hardens. What is this stuff?

F. L. of Caseyville

A: In the spring when the weather gets several days of rain or the mulch stays moist, slime mold begins to form. This is harmless, but it looks like some animal threw up on the mulch. You can remove it with a shovel to an area which is not as noticeable or you can blast it apart with a sprayer at the end of a hose which destroys it as well. Sometimes you can get lucky as it can also be found in bright blue or red color which is interesting to notice. And if you watch it with a wired plastic flag placed near it, you will notice that it moves over the surface of the mulch at a very slow rate of speed. Once the weather gets hot and dry, this slime mold will just dry up and you will not notice it the rest of the year. Because it can move, the slime mold was mysterious as to classify it as a plant or as an animal. Now the biologists have classified this organism in the group with molds.

Charles Giedeman is a local contributing writer. Send your gardening questions to Lifestyle Department, Belleville News-Democrat, P.O. Box 427, 120 S. Illinois St., Belleville, IL 62222-0427, or email them to

Things to do this week

  • Allow the foliage of spring-flowering bulbs to remain until it dries up and turns brown, so it can produce energy to be stored for next year’s bloom.
  • Prune grapes.