Sustainable Landscape News Distributed 02/19/10
By LSU AgCenter Horticulturists Dan Gill, Allen Owings and John Young
February and March signal the beginning of spring in many parts of Louisiana – at least when it comes to getting things done in the home landscape.
February is a time to plant roses, do any pruning that’s needed and continue maintenance of cool-season bedding plants. Adding new bedding plants and shrubs to your landscape and fertilizing some spring flowering plants can be done from early March through mid-April, depending on where you are located in the state. You also should plant ground covers in late winter and early spring.
Summer-flowering shrubs and evergreen shrubs need to be pruned in March; however, spring-flowering shrubs such as azaleas, spiraea, forsythia and flowering quince should be pruned after flowering – this usually means late March through mid-April.
When you prune, preserve the natural form of the plant and have a reason to prune. Thin from within the center rather than shearing the outside of the plant. Be sure to prune azaleas, if needed, by the end of June to preserve next year's flower buds.
Most shrubs can be fertilized in March in south and central Louisiana or in early April in north Louisiana. Use a complete, slow-release fertilizer, such as Osmocote. Broadcast the fertilizer evenly over the entire landscape bed instead of on individual plants. Use a rate of 1-2 pounds of nitrogen per 1,000 square feet or follow the label recommendations. If you have some spring-flowering shrubs, wait until flowering is completed before you fertilize.
Fertilize established ground covers, such as liriope and Asian jasmine, in late March with a general-purpose fertilizer such as 8-8-8 or 13-13-13, and water after broadcasting the fertilizer evenly over the ground cover area. If you are trying to plant or establish a new ground cover bed, do it early in the spring. Ground covers are much slower to establish once we get to the warmer summer months.
You may be eager to plant warm-season bedding plants, but the cool-season bedding plants still have potential to do well into March and sometimes April. Growing conditions were really rough on our cool-season bedding plants during the fall and early winter because of wet weather.
Pansies should still be doing great until the nighttime temperatures warm up a little more. Dianthus, another popular cool-season bedding plant in Louisiana, does great all the way through spring. Leave them in the ground as long as they do well.
You can plant warm-season annuals anytime after cool-season annuals are done. Try petunias for an early March planting, but wait until mid- to late March in central and south Louisiana or early April in north Louisiana to plant the remainder of warm-season bedding plants.
March is also a good time to think about roses. Complete rose planting by early April to get a first flowering in mid- to late spring. Established rose bushes normally will have a major first flowering in early to mid-April, depending on spring temperatures.
You can stay ahead of blackspot disease on roses this spring with a regular fungicide program. Also, watch for thrips, aphids and other insects on your roses. Scout for insects and diseases on your plants and apply insecticides and fungicides only when needed.
Visit LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is near the intersection of Burbank Drive and Nicholson Drive (Louisiana Highway 30) in Baton Rouge, across the street from the LSU baseball stadium. For more information, go to www.louisianahouse.org and www.lsuagcenter.com/lyn.
Rick Bogren