Azaleas are small evergreen shrubs that are in the same genus as Rhododendrons. There are more than 10,000 named cultivars of azaleas, several thousand of which are commercially available. It can be difficult to tell rhododendrons and azaleas apart but two things distinguish them from each other; smaller size and flower growth. While there are small Rhododendrons, most typically have larger leaves and larger growth than azaleas. Rhododendrons produce clusters of flowers on a single stem while azaleas typically have terminal flowers, (one flower per stem). Azaleas however have so many more stems that during their short bloom period the whole plant is typically a mass of color. Most azaleas are equally proportionate meaning they grow roughly as tall as wide. Most azaleas require roughly the same growing conditions however there are a few varieties that have been created to survive more extreme conditions. You should be able to find an azalea that will thrive in your area.

Azaleas fall into two major categories; evergreen and deciduous. There are several evergreen and deciduous species from which hybrid groups were created. The evergreen hybrid azaleas are dominated by six common groups, each with their own unique characteristics. These are:

Gable azaleas
Glen Dale azaleas
Indica or Indian azaleas
Satsuki azaleas
Kaempferi azaleas
Kurume azaleas

Each one deserves a closer look than we give it here and is the subject of more than a few books.

Deciduous azaleas are known for their incredible display of yellow, orange and flame red blooms which can't be found in the evergreen varieties. An added bonus is in the fall when the leaves turn brilliant orange, then red to deep maroon. There are many deciduous species available as well as a popular hybrid group called Knap Hill / Exbury hybrids. Check with your local nursery for availability and suitability in your area.

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General care

Azaleas are easy to grow once you give them the right conditions. While there are varieties which will survive extremes in temperature and light levels, most azaleas require bright but filtered sunlight. In cooler foggy coastal areas, they will often do ok with more direct sunlight. Too much direct sun however can scorch the plant and damage it. Azaleas need an acidic, moist, fast draining soil to thrive. If your azalea's leaves turn yellow, or the plant just seems to collapse, you might have root rot brought about by poorly draining soil. You should amend the soil each year well before bloom with a good azalea fertilizer and compost to supply the energy for sustained blooming. Plant azaleas in a slightly raised bed with the root ball a little above the average soil level. Make sure that the base around the plant remains weed free and maintains good air circulation. A good top dressing of mulch is always good.

Pruning

Pruning is seldom needed but may be useful if your azalea begins to lose its compact shape or becomes leggy. Prune with care by pinching out new growth after the bloom has ended but before the plant begins to set next year's buds. Most azaleas bloom once in the spring and grow throughout the late spring and summer producing buds for next year by late summer. So if you want to control the growth of your azalea, pinch out new growth by the end of June and no later! You may also extend the bloom period by pinching off spent flowers as they begin to fade. This is called deadheading and encourages the plant to produce more flowers because it isn't allowed to produce seed.

Pests

The most serious pest is Botrytis blight. Purple blooming varieties are more susceptible to it than others. This is a grey powdery fungus that attacks the flowers and leaves and can quickly spread throughout an unhealthy plant. Another disease commonly called 'Powdery mildew' is a white fungus that attacks the leaves. This is more of a problem in warm humid environments and is hard to eradicate. The best treatment for both of these is prevention. Make sure that you have good air circulation around the plant, particularly around the base of the plant. Make sure to space plants apart a bit so that air can move freely between them.