It is more than worth the effort to learn how to grow rhododendrons and azaleas because, of the many spring flowers you can have, some of the most spectacular are those of azaleas and rhododendrons.
In temperate zones in the Southern hemisphere azaleas bloom in autumn through to spring.
In areas such as Virginia, early spring flowering is the high period.
The added benefit of course is that they are perennials, unlike annuals which have to be renewed each year.
While they are the same family, they are quite distinctive from each other, though the relationship is apparent.
Rhododendrons are more spectacular and larger, while azalea bushes tend to be smaller in
rhododendron
size and blooms but are hardier in warmer climates.
Conditions
Overall, they prefer reasonably mild, humid climates, but I live in a hot fairly dry climate and get spectacular displays every year. Like anywhere, they thrive best in wind-protected parts of the garden where they can sit in dappled light in well-drained soil enriched with compost and mulch. The red Kurume variety often can be grown in full sun.
If you plant amongst trees, ensure the tree branches are high enough away to allow filtered light to come through. Deep shade will make the plants spindly with fewer flower buds.
The Soil
The soil pH needs to be between 4.5 and 6.0 (nearer to 6.0 is preferable). If you are not sure what you soil pH is – then get an inexpensive test kit from the local nursery and do it yourself. If the soil is too alkaline you will need to adjust it by adding iron sulphate (iron chelates) or peat moss.
The soil is best if loamy. If too sandy or clay – then add mulch for sandy soil and gypsum for clay. Do this on the whole bed, not just the hole where you plant the azalea or rhododendron.
Maintaining the pH is easy – just keep the soil well mulched and feed them once a year with specific fertiliser and use cow manure. One way to keep an eye on the pH is to grow a blue hydrangea with them. If it starts to revert to pink or white, then the alkaline level may be coming back.
Care
The roots of these two plants are fairly delicate and care has to be taken not to damage them when digging near them. Mind you, if you have mulched well over the years there is no need to ever dig over a garden anyway.
Use fertilisers that are formulated specifically for acid loving plants. Once established azaleas and rhodos need only feeding after flowering (April /May in the Northern hemisphere; November in the Southern). Don’t apply fertilisers that are general garden fertilisers.
If you maintain good mulching habits, this will control weeds with little need for recourse to herbicides. This is also good environmental practice.
Pruning
Generally they need little, if any pruning. If growth is excessive, then only do a light pruning. Don’t do it after mid-summer as this will stop good bud formation for the flowers that will come in autumn and winter.
Varieties
There is a huge number of varieties of azaleas and rhodos. Check with your nursery and see what is available – they will normally be those best suited for your region’s climate and soil.
