Careful choices matter when it comes to plants

Richard Bogren, Gill, Daniel J.  |  1/4/2011 1:15:23 AM

For Release On Or After 04/02/10

By Dan Gill
LSU AgCenter Horticulturist

Fragrance is a plant’s way of touching us without physical contact. Like many things we enjoy in nature, the perfume is not really intended for us – but it seems like it is, anyway. If you love fragrant plants in the garden, you will be thrilled with our native honeysuckle azalea.

Flowering mid-March through early April, honeysuckle azaleas (Rhododendron canescens) produce a light, sweet fragrance that permeates the air. Honeysuckle azaleas are native to Louisiana and throughout the southeastern United States from North Carolina to Florida and east to Texas. You often will find them growing along sandy creeks in mixed pine and hardwood forests throughout the state, except in the southern coastal parishes.

All azaleas belong to the genus Rhododendron. The most common azaleas used in our landscapes are evergreen types derived from species native to Asia (China, Japan and Korea). All of our native azaleas, including the honeysuckle azalea, are deciduous and drop their leaves in the winter.

Another group of plants that belong to the Rhododendron genus have larger, leathery evergreen leaves and produce their flowers in large clusters at the ends of their branches. These plants are commonly called rhododendrons. Better adapted to climates with colder winters and milder summers, they typically will not thrive down here, although cultivars adapted to the Deep South are being developed and may be available in a few years.

Because native honeysuckle azaleas are deciduous, many people immediately would consider them undesirable. Louisiana gardeners who only want evergreen shrubs feel that when a shrub drops its leaves, it looks dead and unsightly. Deciduous shrubs such as hydrangea, Virginia willow, flowering quince, red buckeye, mock orange, althea and others, however, make outstanding additions to the landscape.

Deciduous shrubs help bring a feeling of changing seasons to an otherwise fairly static landscape. In the case of honeysuckle azaleas, it enhances the flowering since the blossoms appear before the foliage. Without the distraction of the leaves, the flowers are even more noticeable and persist until the leaves begin to emerge.

The flowers of honeysuckle azaleas range from dark pink to white, are about 1 to 1 1/2 inches across and occur in clusters of six to 15 at the tips of the branches. Commonly grown evergreen azaleas are typically mound-shaped, but this native azalea is more upright and oval in form with a medium texture and loose, open branching. It generally grows about 6 feet tall but occasionally reaches 15 feet with age and good growing conditions. The growth rate is relatively slow, and little pruning is usually necessary.

These shrubs perform well in full sun to part shade, but many gardeners have had best results providing some shade during the day – especially in the afternoon. Planting in deep shade greatly reduces flowering, although the plants will survive.

Honeysuckle azaleas grow best in an acid soil rich in organic matter with excellent drainage and an even supply of moisture. This is not terribly different from recommendations for the familiar azaleas.

The best results come from well-prepared beds made with thoroughly incorporated, generous amounts of compost or finely ground, composted pine bark. Add a soil acidifier, such as copperas, if your soil is alkaline. If you suspect the drainage is not excellent, plant your azaleas in raised beds. After planting, apply a 2- to 3-inch layer of mulch, such as pine straw or leaves, under the shrub to help maintain even moisture.

Regular watering is important, especially during hot, dry weather in late summer. Honeysuckle azaleas set their flower buds in July, and drought at that time can reduce flowering the next spring.

Fertilize them at the same time and rate as your other azaleas. Use a fertilizer formulated for acid-loving plants following package directions carefully. The foliage of native azaleas is naturally a light green, so don’t fertilize excessively trying to make the leaves darker.

We are not accustomed to seeing yellow and orange azalea flowers. None of the Asian species produce flowers in those colors. But a relative of the honeysuckle azalea called the flame azalea (Rhododendron austrinum) produces flowers in shades of yellow, gold, orange and red.

Looking very much like the honeysuckle azalea except for the flower color, its culture is the same. Plant breeders currently are hybridizing these two species with other related, native azaleas to produce a range of flower colors, shapes and sizes. All are upright, deciduous shrubs distinctively different from traditional azaleas, and most produce a sweet fragrance that fills the air with the magic of spring.

Rick Bogren

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