Azaleas and Rhododendrons

Azaleas and Rhododendrons belong to the same family of plants as the heather's (Erica and Calluna) and the southern heather's (daboeca).

The Rhododendron family is devided into elepidotes and lepidotes. Azaleas are all 'elepidotes',do not have scales on the underside of leaves or stems. Rhododendrons are 'lepidotes', which have scales and they are usually on the underside of leaves but some do have scales on the top side and on stems. An easy way to differnciate is that azaleas have 5 lobes to each flower and generally only one stamen, rhododendrons have two stamens for each flower lobe and can have 5, 6 or 7 lobes so each flower will have 10 or more stamens. There are exceptions to these rules as with other botanical classifications

There are species and hybrids, hybrids are produced by crossing two species or two hybrids or one of each to create a new hybrid. It is very difficult to cross a lepidote with an elipidote.

They are termed 'calciphobes', meaning they cannot tolerate Lime in their soil, soils with a Ph of greater than 7.0. Here in the UK most garden centers stock 'Ericacious' compost and they should be grown in this. If this is unobtainable where you are then a compost high in natural peat, or leafmold can be used.

Most calciphobes will benefit from an occasional watering with 'seqestered iron', usually available in garden stores.

Azaleas are particularly delicate after repotting. They have a very fine surface roots, which are, if not kept moist during and after repotting, liable to die. This can be cured by constant spraying, during repotting, then covering the surface of the pot with a 'mulch' to keep the moisture in. Florists moss is often used in this case.

The Azelea family are best kept in a semi-shade location as they are , like most trees prone to leaf damage if they get dry.

Azaleas and Rhodedendrons respond well to pruning, often back-budding far into old growth. Snapping, or cutting the new growth off early in the year, will induce hidden buds to shoot as shown in the lower picture.

Allen. C. Roffey Saturday, August 4, 2018 22:00