Get it growing

Gardening with perennials

LSU AgCenter News

February 03, 2011 at 10:09 am  | Mobile Reader | Print 

Most Louisiana landscapes contain a variety of perennials, and February is a good time to transplant or divide them. Perennials are plants that live for three or more years unlike annuals, which die after flowering and setting seeds. Because they will become a part of your garden for years, using perennials effectively requires learning more about each variety.

Transplanting

If they’re transplanted now, most perennials will barely miss a beat if you’re careful to dig up most of the root system and replant it immediately in a new location. Don’t transplant perennials if they’re in active growth at this time, such as Louisiana irises, acanthus, calla lilies and Easter lilies.

Dividing
Some perennials are best divided every year or two, but most can be left alone for two to three years or even longer. Dividing helps control the size of the plant and the space it occupies, as well as rejuvenate it. To divide a perennial plant, first dig up the entire clump using a shovel or garden fork.  Decide where to make cuts so you avoid cutting through crowns or damaging shoots. Finally, cut apart the clump with a large, sharp knife. Replant or pot the divisions immediately.

Planting

Early spring is a good time to plant perennials, but they may not look like much when you purchase them in late winter or early spring. Plant perennials into well-prepared beds, and space them according to information on the label. When you plant a perennial, make sure the top of the root ball is even with or slightly above the soil of the bed. If the roots are in a tightly packed mass, pull them apart and spread the roots out somewhat when planting. Firm the soil around the plant, then water newly planted perennials thoroughly. Mulch the bed to control weeds, but don’t cover the plants.

Selecting perennials

Reject varieties that only grow well north of hardiness zone 8. To survive here, perennials must be able to endure the heat, humidity and rain of summer and the diseases that season brings.

Also note the growing conditions that exist in your landscape and select perennials that will thrive in those conditions. Consider plant and stem heights. And don’t forget to choose perennials with a variety of textures and growth habits to create interest and contrast in the visual composition. Flower colors also are very important. Decide on a color scheme and select perennials that bloom at various times of the year for extended displays of color.

For more information and recommendations of perennials that do well in Louisiana, consult “Perennial Garden Color” by William Welch and “Perennials for the Coastal South” by Barbara Sullivan.