Sustainable Landscape News Distributed 04/03/09

By LSU AgCenter Horticulturists Dan Gill, Allen Owings and John Young

Late March through early May is the prime time for planting our spring annuals in Louisiana. Warm-season bedding plants make a great addition to our home and commercial landscapes.

We have an abundance of terrific, colorful plants that do well. Popular warm-season bedding plants include impatiens, periwinkle (vinca), coleus, begonias, caladiums, marigolds, zinnias, salvia and many others.

Incorporate the following “best management practices” to enjoy warm-season bedding plants from spring through the fall:

– Properly prepare landscape beds to allow for good internal drainage and aeration. This is essential to get plants off to a good start and to avoid root rot and other diseases.

– Add fresh, nutrient-rich, finished compost to landscape beds to provide nutrients.

– As a traditional fertilizer approach, apply a slow-release fertilizer at planting.

– Make sure landscape beds have a soil pH between 5.5-6.0. The majority of warm-season annual bedding plants we grow prefer this soil pH range.

– Monitor the sun and shade situation, and select the right plants accordingly. Most full-sun plants need eight hours of direct sun a day. Partial-sun plants like six hours of direct sun daily. Partial-shade plants need some direct sun daily – normally two to four hours – and shade plants need little direct sun (less than two hours daily) to do well.

– Early April through early May is ideal for planting, but many warm-season plants can continue to be planted through late spring and summer. For example, marigolds and zinnias are great flowering plants in the summer and also will have flowers in late summer and fall.

– Choose varieties recommended for Louisiana’s growing conditions. New varieties to consider include Profusion zinnias, Dragon Wing begonias, Moonstruck marigolds and Titan, Cora and Nirvana vinca.

– Irrigate only when necessary. Overwatering leads to many problems with root rot, petal blight and leaf spots. Apply irrigation to the soil and mulch area, not on plant foliage.

– Be aggressive, and plant in masses for the best visual enhancement. Light colors go well in the front of beds with darker colors toward the center and back of beds. Short plants should be planted in the front of beds with taller-growing plants toward the center and back of beds.

– Remove old flowers from plants to extend the bloom season. This is called “dead-heading” and will extend the bloom season on marigolds, salvia and zinnias.

The LSU AgCenter conducts annual bedding plant evaluations at LaHouse in Baton Rouge in additional to at Burden Center in Baton Rouge and at the Hammond Research Station in Hammond.

Come to LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is located near the intersection of Burbank Drive and Nicholson Drive (La. Highway 30) in Baton Rouge across the street from the new LSU baseball stadium. Go online to Louisiana Yards and Neighborhoods for additional information.

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Editor: Mark Claesgens