Q. During the past few
weeks, I have enjoyed the brilliant blooms of my azaleas and my
neighbors' azaleas and rhododendrons.
Are there major differences between these plants? The rhododendrons
are larger, but the flowers appear to have a similar shape. Is it
true they can survive with very little watering?
Rhododendrons and azaleas both are classified in the genus
Rhododendron, so you are correct that they are very similar.
not always larger than azaleas; some grow only 18 to 24 inches tall.
There is tremendous variation in this genus, so it is difficult to
set hard and fast rules for telling the difference.
Mature 'Herbert' azalea
While there are exceptions, the following differences
usually hold true:
flowers usually have 10 or more stamens, while
have five. Stamens are the pollen-bearing male reproductive
organs found inside the throat of a flower. (The ovule-bearing
female reproductive organs are called pistils.)
- Rhododendroms usually are evergreen, while most azaleas are
deciduous (lose their leaves in fall), including all of the
azalea species native to Western Pennsylvania -- R. arborescens,
R. periclymenoides and R. viscosum. That said, evergreen azaleas
are more commonly grown as ornamentals in Western Pennsylvania
leaves may be scaly or have small dots on the underside of the
leaves. A few rhododendrons have dense, soft hairs on the
undersides. Azalea leaves, both deciduous and evergreen, are
often covered top and bottom with fine hairs.
rhododendron flowers are borne in terminal clusters known as
trusses; azalea flowers are often borne singly or in small
are members of the Heath family, or Ericaceae. In general, members
of this family prefer a well-drained, yet evenly moist, acidic soil
that has good organic matter content. Our native species, both
deciduous and evergreen, usually grow as understory plants in the
high shade of mature trees, often along streams. They are not
considered extremely drought resistant. They actually require an
even, adequate source of moisture. They tend to be shallow-rooted
plants and perform best when protected from strong winds, especially
in the winter.
indoors at summer's end