By Heather Kirk-Ballard

LSU AgCenter Horticulturist

(12/13/19) We’ve finally gotten a reprieve from cutting grass and hot weather. It’s time to put away the mowers and weed trimmers. The winter months provide us an opportunity to focus on landscape planning, planting and maintenance.

It may seem counterintuitive, but once temperatures have cooled, it is the perfect time for planting trees and shrubs in the landscape. The winter months offer trees and shrubs time to establish roots before spring growth. This is the perfect scenario for planting. A well-established root system is fundamental to a healthy plant.

Some native trees for your consideration include honeysuckle azalea, red buckeye, Eastern red cedar, fringe tree, parsley Hawthorne, ironwood, wax myrtle, redbud, river birch and yaupon holly. Also look for Louisiana Super Plants at your local nurseries. These plants are tested and selected for their outstanding performance around the state and are university tested and industry approved.

Hardy shrub Super Plants that can be planted now include Belinda’s Dream roses, Drift roses, Shishi Gashira camellias, Henry’s Garnet sweetspire, Conversation Piece azaleas and Leslie Ann sasanquas. Also consider natives such as American beautyberry, dwarf yaupon holly, dwarf palmetto, star anise, mountain hydrangea, Virginia sweetspire, inkberry and other native viburnums.

Cool-season bedding Super Plants that can be planted now include Homestead Purple verbena, Swan columbines, Redbor kale, Camelot foxgloves, Amazon dianthus, Jolt series dianthus, Sorbet violas, Supertunia Vista Bubblegum petunia and Mesa gaillardia.

Besides planting, winter is also a great time for equipment maintenance. Now that the landscape equipment is effectively retired for the season, is the perfect time to sharpen mower blades and take care of any mower or weed trimmer maintenance. Check spark plugs and change the oil in equipment. You can also sharpen tools and oil them to prevent rusting.

Other things you can do in the landscape beds include planting:

• Tulip and hyacinth bulbs in late December or early January. Remember, tulip and hyacinth bulbs must be refrigerated for six to eight weeks before planting.
• Hardy perennials delphinium, foxglove and French hollyhocks.
• Annuals that bloom in winter, such as alyssum, calendula, dianthus, hollyhock, lobelia, flowering cabbage and kales, pansies, snapdragons and violas.
• Gladiolus in late February in south Louisiana. Prolong the blooming season by planting at two- to three-week intervals for a couple of months.

Here are some maintenance duties for winter:

• Rake fallen leaves of deciduous plants and trees to use as a mulch or to compost.
• Prune landscape trees, shrubs and evergreen plants that do not flower in the spring. But do not prune spring-blooming azaleas, hydrangeas or spireas.
• Prune ever-blooming roses in late January or early February. Landscape roses, like the popular Knock Out roses, should be cut back by about one-half their height but not lower than 2 feet from the ground.
• Trim ever-blooming roses at the end of January to flush out a new blooms for the spring.
• Mulch to protect the roots and rhizomes of tropical landscape plants, citrus and other cold-sensitive plants. Spread a 4- to 6-inch layer of pine straw, pine bark, leaves or straw mulch around the base of the plants or cover the entire landscape bed. Be sure to bring in any tropical plants in containers to protect them from freezing temperatures.
• Deadhead or remove old flowers from your cool-season bedding plants to extend the bloom period and improve flower performance.

January and February are the ideal time to fertilize young trees and shrubs in preparation of rapid spring growth. Fertilize shrubs with one-quarter pound of compete fertilizer per square yard, and fertilize trees with 1 to 2 pounds of fertilizer per year of age.

For trees, use a granular fertilizer with a 3:1:2 ratio such as 15-5-10. The amount is based on the square footage of tree roots based on the ratio of 20 pounds of fertilizer per 1,000 square feet.

Here’s how you calculate: Measure the distance from the trunk of the tree to the drip line of the canopy where the branches reach then multiply by two because roots grow out twice as far as the branches. Multiply that number by itself and then by 3.14 to determine square footage.

You can also begin a preventative spray program for roses by alternating fungicides for blackspot and powdery mildew.

Watch for lace bugs on azaleas in February. They cause the foliage to have numerous small white spots, and they feed underneath lower foliage. Control them with horticultural oil sprays or a systemic pesticide. Always remember that healthy plants can ward off insects and disease, minimizing the need to use pesticides, so always give them the best environment, water and nutrients.

Look for straight trunks when choosing a tree in a nursery. LSU AgCenter file photo by Dan Gill

Tulips are a floral treat in Louisiana, but they have to be properly planted for top results. LSU AgCenter file photo by Dan Gill

Prune ever-blooming roses in late January or early February. Photo by Rick Bogren/LSU AgCenter

Pruning trees needs to include evaluating branches for future growth considerations. LSU file photo by Allen Owings