Growing Azaleas as Garden or Patio Shrubs
These Ornamental Flowering Bushes Produce Masses of Colourful Blooms
May 28, 2009
Azaleas are a sub group of the rhododendron family. Although they have many similarities they tend to be smaller than other rhododendrons, and many, though not all, are deciduous. An added attraction is that a number have sweetly scented flowers. Most varieties have large trusses of bold white, pink, orange, red, blue or purple blooms, often with splashes of contrasting shades.
Individual azaleas generally have a relatively short, albeit brilliant, flowering season. However, collectively they produce a display which can last from early spring to mid summer. Evergreen varieties have attractive glossy green leaves while the deciduous have pale green leaves, and in some cases colourful autumn foliage.
Most azaleas are fully hardy. Their main disadvantage is that they need a lime free soil. With this qualification, there’s an azalea to suit every garden, however large or small. The largest, rarely grow to a height of more than 8 ft after 10 years, while the dwarf Japanese evergreen varieties only grow 1-2 ft high and are ideal for patio or container cultivation.
Cultivation and Pruning
- Azaleas are naturally woodland plants, growing in a loose and friable, moist, well drained acid soil, and in the dappled shade of larger trees, although many will tolerate full sun.
- If your garden has a neutral to lime free soil, plant azaleas as you would with any other shrub, digging plenty of peat or lime free ericaceous compost around the roots.
- Top dress annually with peat or leaf mould and feed with ericaceous compost or sequestrene.
- If your soil is alkaline, all isn’t lost. Create a raised bed or dig out a generous hole lined with permeable plastic and fill the bed with peat and ericaceous compost or other lime free soil. After planting top dress with ammonium sulphate in spring and autumn.
- However, creating and maintaining these conditions artificially demands continuing effort. An easier solution is to grow your azaleas in pots filled with ericaceous compost.
- Always water azaleas with rain water rather than hard tap water.
- No pruning is normally needed, but they will stand being cut back hard immediately after flowering.
- Do not cut grafted varieties too hard.
Azalea Species and Hybrids
There are a number of different species of azalea and many hybrids. The small selection of popular and widely available varieties below are examples of the characteristics of their respective groups and give an idea of the assortment available:
- Rhododendron Albrechtii. ( Deciduous Species Azalea). Open, clematis-like 1 ½ inch pink flowers in April and May. Height and spread 8ft x 8ft. Hardy, but best in a sheltered position in part shade to protect the early flowerbuds from damage.
- Rhododendron Luteum. ( Deciduous Species Azalea). Star shaped trumpets of fragrant yellow flower in May. Height and spread 8ft x 8ft. Very hardy. Brilliant autumn foliage.
- Rhododendron Occidentale. ( Deciduous Species Azalea). Large clusters of splendid fragrant white flower, flushed with pink with yellow interior markings, in June. Height and spread 8ft x 8ft. Hardy in most areas.
- Rhododendron Reticulatum. ( Deciduous Species Azalea). Star shaped purple blooms in May. Height and spread 8ft x 8ft. Very hardy.
- Rhododendron Coccineum Speciosum. (Ghent Azalea Hybrid). Clusters of brilliant orange trumpet shaped flowers in May. Height and spread 8ft x 8ft. Deciduous. Very hardy.
- Rhododendron Fireball. (Knaphill Exbury Azalea Hybrid). Clusters of brilliant fragrant red trumpet shaped flowers in May. Attractive bronze/green foliage. Height and spread 8ft x 8ft. Deciduous. Very hardy.
- Rhododendron Japonica Blue Danube. (Evergreen Japanese Azalea Hybrid). Mauve blue trumpet shaped flowers in May. Height and spread 3-4 ft. Evergreen. Very hardy.
Other Similar Garden Plants
If you can grow azaleas in your garden, you’ll also be able to succeed with rhodendrons and camellias.
