Garden Plants - Azalea

Okay, what's the difference between a rhododendron and an azalea? You don't know? Neither do I, to be honest, so let's see if we can find out. The term azalea comes from the Greek for dry, or azaleos, and was originally used to cover a variety of species plants and hybrid rhododendrons - which is not helpful in terms of definition, because most azaleas don't do well in dry ground and need to be well watered because they have a shallow rooting system.

The first plant that we would still identify as an azalea reached England in around 1690. It was commonly called the 'swamp azalea' By 1737 Linnaeus, the father of taxonomy (or names) was applying the name to a series of shrubs from dry habitats in Lapland, but that doesn't help us, as they have since been renamed Loiseleuria. Then in, 1834, another naturalist decided it was time to correct Linnaeus. He was an Englishman, called George Don, and he separated the genus Rhododendron into eight sub-categories, composed of numerous species. The azaleas comprise two of these sub-categories - that is evergreen azalea bushes and deciduous azalea bushes.

What does this mean? Well, if you read the scientific name of an azalea, you'll see the word, Rhododendron. That's because azalea plants belong to the genus, Rhododendron - and the term 'azalea' or dry has essentially become this bush's common name. Can you tell them apart - maybe, if you're very good indeed: Rhododendron have large, leathery, evergreen leaves. The leaves on azalea plants tend to be smaller, by comparison. In general, rhododendrons are larger shrubs than are azaleas. At the right time of year it becomes a lot easier - azalea flowers have five stamens, while the rhododendrons have ten. Finally, unlike rhododendrons, many azalea plants are deciduous

Garden Azalea photograph by Xerones, used under a creative commons attribution licence