Larry Smith and the Riverside Gardens team talk about all things pots, plants and pruning in their weekly gardening column.
With wattles coming into flower and fields of golden canola popping up everywhere, it is easy to see that spring is not far away at all.
If it’s not happening already, you will see azaleas and rhododendrons coming into prominence in gardens around the area. Although this area is not known as being ideally suited for growing these plants, given the right position in the garden and the right care, they will do very well.
Azaleas, as we commonly call them, are actually a variety of flowering shrubs from the rhododendron genus but are generally referred to as two separate groups.
Azaleas are mostly small to medium-growing shrubs reaching up to 1.5m high and they roughly fall into three main groups.
Azalea kurume is a smaller-growing variety of azalea. It has small, rounded leaves that almost disappear completely beneath the impressive display of flowers each spring when its small starry flowers open in mass over the whole shrub. This floral show can last for up to three to four weeks at a time, with some varieties having spot flowers again later in the year.
Azalea indica is a larger-growing variety with larger elliptical leaves. Its flowers are also larger, but they are much less abundant and open, dotted over the shrub rather than in mass. While its bigger flowers still give a stunning display, they do not achieve the same colour impact as the azalea kurume.
Mollis azalea is a medium upright shrub with bunches of impressive trumpet-shaped flowers in late spring to summer. It is a deciduous variety of azalea with a soft ovate leaf that can colour up nicely with reds and oranges in autumn. These plants are mainly available in garden centres in late spring as they start to bud up, while azalea indica and azalea kurume are both available now and continue to be through most of the year.
Azaleas require a cooler, shaded position in the garden. Ideally suited to growing under light canopied trees or an easterly aspect in the garden with protection from the hot late-afternoon sun. There are a few varieties that are marketed as full sun or sun-tolerant varieties, but that refers to more cooler regions rather than to our hot, dry summer heat. There are a few exceptions to this, but be aware and ask questions if you are unsure.
Being shallow-rooted plants, they appreciate having their root area mulched and cool. They like well-drained, moist soil but can tolerate heavier clay-type soils if built up. They do, however, require slightly acidic soil and do best in a pH of around four and a half to six. A light trim after flower and a feed with an appropriate fertiliser will see your plants bush up and harden off before the real heat of summer.
Azaleas are prone to attack by spider mites and lace bugs, not to be confused with lacewing, which is a beneficial predatory insect. Both pests can be controlled if you know what you are looking for and act once identified. The tell-tale sign is a silver-mottled appearance of the leaf, which, when turned over, reveals tiny black dots or insects on the underside. There are several ways to control these pests, including both chemical and natural sprays, so you are best off dropping into the garden centre and asking what best suits your needs.
As mentioned earlier, rhododendrons are also coming into flower soon, and new season stock will be appearing in garden centres over the next few weeks.
However, with their much bigger leaves, they are more prone to water loss and heat damage through our hot, dry summers. Choosing the right varieties is a lot more critical, but the right variety, grown in a cool, shaded position, can become a real feature in your spring garden. They require the same care and maintenance as their smaller cousins, but like their smaller cousins, the rewards are well worth it.