Azalea

Azalea

Rhododendron 'Hinodegiri'

Plant Info

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Ericales
Family:	Ericaceae
Genus:	Rhododendron
Subgenus:	Pentanthera and Tsutsuji

Species

see text

Source: The Rhododendron page, and some research.

Azaleas are flowering shrubs making up part of the genus Rhododendron. Originally azaleas were classed as a different genus of plant, but now they are recognised as two of the eight sub-genera of rhododendrons - subgenus Pentanthera (deciduous), and subgenus Tsutsuji (evergreen).

Differences

A bush of azaleas.

One major difference between azaleas and the rest of the rhododendron genus is their size. Another is their flower growth; rhododendrons grow their flowers in stripers, while most azaleas have terminal blooms (one flower per flower stem). However, they have so many stems that during the flowering season they are a solid mass of colour. Azaleas are recognised by these flowers blooming all at once, in a showy display for a month or two in spring. The exception to this rule is a small group of azaleas which grow their flowers in tight terminal clusters.

An azalea flower close up

The Satsuki azalea group, derived from Rhododendron indicum and related species, are very popular.

A traditional alcoholic beverage made from azalea blossoms, called Tugyonju (literally "azalea wine"), is produced in Korea.^[1]

Also, azaleas are the most common toxic plant that dogs ingest.Template:Fact

Cultivation

Plant enthusiasts have created azaleas for hundreds of years. This human genetic modification has produced over 10,000 different cultivars which are propagated by cuttings. Azalea seeds can also be collected and germinated.

Azaleas grow best in well-drained soil or in plant pots in a cool, shady position. They are easily damaged by excessive soil moisture and grow best in acidic soil (4.5 - 6.0 pH).^[2] Fertilizer is optional, although some species do need regular pruning.

Several commercial nurseries in Semmes, Alabama, a suburb of Mobile, are major national suppliers of azaleas in the U.S.

Disease

Azalea leaf gall can be particularly destructive to azalea leaves during the early spring. Hand picking infected leaves is the recommended method of control. Information on azalea leaf gall can be found on Cornell University's Plant Disease Diagnostic Clinic web site. Azalea Leaf Gall Fact Sheet

Fifty year old Azalea

A close up of a red azalea flower

References

External links

[1] Korean tradition

[2] Clemson University Factsheet

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