Advice on Azaleas

Azaleas are the most widely used woody ornamental shrub in Louisiana in spring, pointed out Allen Owings, horticulturist, Louisiana State University AgCenter, Baton Rouge, La.

But when it comes to azaleas, several spring installation and maintenance tips need to be considered to ensure success, Owings stressed. These include proper bed preparation and site selection, mulching, fertilization, pruning and pest management."Probably the most important consideration for optimum performance of azaleas is proper landscape bed preparation," Owings emphasized, adding that this means providing loose, well-drained soil. "This requires making raised beds or providing a considerable amount of amendments to our existing soils."

Surface and internal drainage in a landscape bed also must occur, since azaleas are very sensitive to poor drainage and aeration, according to Owings, who says this condition creates major root rot and related problems.The ideal soil pH for azaleas is 5.0-6.0, which is considered to be slightly to moderately acid. "When selecting a site for azaleas, consider the soil situation but also consider a southern and eastern exposure, because this is favorable to a northern or western exposure," Owings advised. "

Azaleas are best adapted to a partially shaded areas, and sunlight during morning hours is favorable for growth and flower bud development."Another key to success with azaleas is to provide mulch to conserve soil moisture, Owings says. "Excellent mulches include pine straw needles, pine straw shaving, cypress mulch and pine bark products," he said. In addition to the benefits of helping with soil moisture, mulching also increases the aesthetics of a planting bed, suppresses weed growth, adds organic matter to the soil and minimizes soil temperature changes.

Azaleas also need fertilization to perform well. Owings said contractors should fertilize in early spring or shortly after flowering with a complete slow-release fertilizer. A recommend rate is 1-2 pounds of nitrogen per 1,000 square feet of bed area, according to Owings, who says a foliar feeding with iron also will improve foliage color.

As for pruning, Owings recommended contractors trim plants after flowering in the spring. "Remove a small amount of wood from inside the plant canopy every year," he said. "But try not to shear across the top of plants unless clients desire the formal appearance that will result.

At any rate, be sure to perform a complete pruning by early July to avoid removing next year’s flower buds."Several pest problems also occur in azaleas in Louisiana. The most common of those problems is damage from lacebug feeding, which results in a mottled discoloration with speckles of dark excrement.Infestation usually begins in late winter and early spring. Owings recommended contractors monitor azalea plantings every two weeks for this insect.

The author is Managing Editor of Lawn & Landscape magazine.