Alpine Rose - Azalea

Azaleas - Beautiful Flowering Shrubs for Your Garden

Azaleas are certain species of mostly deciduous rhododendrons belonging to the heather family (Ericaceae). They attract attention primarily with their brilliantly colored flowers, which can completely cover the plant.

Rhododendron colors range in shades of yellow, orange, red, and purple, with some species featuring white or violet-blue flowers. Their fragrance is also attractive and can be very intense and intoxicating.

Azaleas bloom from January to August, with outdoor species in our conditions typically flowering in April and May.

There are more than 1,000 species of rhododendrons and azaleas and countless different cultivars, including evergreen and deciduous species, suitable for indoor, balcony, and outdoor growing.

Among rhododendrons, we find predominantly shrubs (sometimes small trees) ranging in size from several dozen centimeters to several meters.

In this article you'll find: how to choose the right plant, site selection, azalea care

How to Choose the Right Plant

First, consider where you want to place your azalea. There are many species for outdoor cultivation, most of which will thrive better in shade. You can also find rock garden azaleas, which are characterized by smaller growth and delicate foliage.

If you're looking for an indoor azalea, it will most likely be the species Rhododendron simsii.

When you buy an azalea or rhododendron in spring, you'll probably be able to see the exact flower color and enjoy the blooms in the first year in your garden.

However, plants that are currently fruiting, flowering, or preparing to bloom develop root systems very poorly. This is due to hormone levels that allow the plant to concentrate energy on reproductive organs.

This is especially risky if the roots were damaged, dried out, or if the plant didn't have enough moisture after planting. For safe azalea development, it's therefore better not to plant during the spring period.

In autumn, rhododendrons have already finished flowering, so you can't immediately enjoy their splendor. They may also not be in the best condition after a long six-month stay at the retail outlet.

Therefore, you need to pay extra attention when choosing the species, variety, and specific plant. However, an azalea planted in autumn isn't exposed to the danger of exhaustion and inability to form roots due to flowering.


If you've selected a healthy plant, the risk of death is minimal and the following spring will delight you with an abundance of flowers.

If azaleas are sold bare-root, they should ideally be freshly dug, preferably with still moist roots and soil. Also check that the roots are healthy, with fine root hairs and not affected by rot.

It's even better to buy a plant in a pot, where there's no risk of root damage. The leaves should be firm and glossy, with no signs of pest infestation (sticky spots, spider webs, colored or brown patches).

Where Your Azalea Will Thrive

Most rhododendrons thrive best in a shaded location with diffused light. A good spot might be shade on the north or west side of a building or slope, or the space under a tall tree.

Rhododendrons particularly tolerate morning sun and freezing wind poorly. Leaves can also be scorched by spring sunshine, as the azaleas haven't yet adapted to it after winter, or they should be protected by a tree that hasn't leafed out yet.

Some species, especially rock garden azaleas, on the other hand welcome sun, sometimes even direct sunlight. More sun promotes flower bud formation. You'll find out which type your azalea belongs to when you purchase it.

Indoor azaleas usually prefer partial shade through winter, and in spring they benefit from diffused light or even direct sun. However, they need to be gradually accustomed to it. If possible, give them time outdoors somewhere, perhaps on a balcony.

Suitable soil for azaleas is acidic and moist. They tolerate neutral or even alkaline soils poorly. If your soil is too alkaline for azaleas (usually due to high calcium content), it can be amended by adding a larger amount of peat to the planting hole. In subsequent years, use peat for mulching.

How to Keep Azaleas Thriving

The foundation of azalea care is watering, fertilizing, mulching, and deadheading spent flowers.

Watering is very important, as azaleas are accustomed to a constant water supply. The roots should never dry out. Water indoor azaleas in the morning with soft, preferably rainwater (it's important that it doesn't contain calcium, which is common in tap water).

Once a week, you can immerse the entire pot with the azalea in water for a few minutes. In winter, reduce watering only enough to prevent the soil from drying out completely.

Outdoor rhododendrons require moist soil or frequent watering.

If autumn is dry, rhododendrons can suffer from drought even through winter - given that they usually don't drop their leaves, they continue to breathe lightly and evaporate water through the leaf surface.

Beware of excessive waterlogging, as it can cause fungal diseases to develop. Deciduous azalea species typically don't have moisture problems through winter.

We fertilize mainly through watering, for indoor azaleas from mid-winter when they start to bloom, and for outdoor species in spring. The most suitable is fertilizer specially designed for azaleas, which contains a balanced ratio of macro and micronutrients just for them.
Plants grown in containers are fertilized until the end of summer every two weeks, through autumn and winter we fertilize less. Outdoor plants are fertilized only during the growing season.

It doesn't pay to underestimate or neglect fertilization - plants with nutrient deficiency bloom little or not at all, grow slowly, wither and are more susceptible to diseases and pests.

Azaleas have shallow roots, so pots should be wider rather than deep. For outdoor plants, this must be kept in mind and the soil around them should not be dug up.

Annual mulching is more suitable, where we spread up to 10 cm high layer of peat or compost around the azalea. Peat retains more moisture and acidifies the soil, compost provides nutrients and humic acids.

Rhododendrons usually don't require pruning because the shrubs maintain a compact shape on their own. However, old plants sometimes need rejuvenation, as they can become bare on the lower part of branches.

We also want to maintain indoor azaleas in a certain shape. If pruning is necessary, it's advisable to choose early spring or late winter, when there's no longer a threat of frost and azaleas haven't started blooming yet.

This prevents exhausting the plant during fruit formation and promotes branching.
For indoor species, this can be even earlier. They tolerate deep pruning quite well, as long as it's not done too often.

Give your azaleas the best! Quality fertilizers tailored specifically for these beautiful plants can be found directly in our e-shop!

Written by Eliška Kadlecová