- Azalea: flower, origin and properties
- Plant azalea as a houseplant
- Planting azaleas in the garden
- Wintering azaleas: Which azaleas are hardy?
- Propagation of Azaleas
- Are azaleas poisonous?
- Common pests and diseases
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The azalea inspires with its bloom both in the garden and in the apartment. Here you can find out how to plant the azaleas correctly and how to overwinter them.
Because there are not only indoor but also garden azaleas, location and care must be adapted to the corresponding needs of the species. We show how pot azaleas differ from outdoor azaleas and what to look out for when planting azaleas.
Azalea: flower, origin and properties
Azaleas are trees and shrubs of the genus Rhododendron and come from Asia. However, they used to be considered a separate genus Azalea. What is special about azaleas is that you can keep them both outdoors and indoors. The respective groups are referred to as garden or outdoor azaleas and as room or potted azaleas according to their attitude. There are deciduous and evergreen representatives of the trees. These all grow bushy and can reach a height of between 40 and 150 cm. The leaves are entire and egg-shaped, shiny or white flocked. The azalea flowers are eye-catching and come in a wide variety of colors. There are also varieties whose funnel-shaped flowers are filled. Others have simple flowers. The flowering time of azaleas depends on whether it is a garden or houseplant. The indoor azaleas bloom earlier, sometimes from September to April. Garden azaleas, on the other hand, begin flowering in April and continue flowering until August.
Difference between rhododendron and azalea: Whether it is an azalea or a rhododendron is difficult to define. All azaleas are rhododendrons. Some Rhododendron-types are summarized under the name Azalea: Frost-sensitive, evergreen indoor azaleas and hardy, winter- or deciduous azaleas, which only thrive well outdoors. Outdoor azaleas either shed their foliage or change their foliage annually in spring. In contrast, rhododendrons are evergreen, they change their foliageconsistently throughout the year and not intermittently in spring.
Plant azalea as a houseplant
If you have decided on an indoor azalea, there are a few points to consider. If you have chosen a suitable location and taken the right care measures, you will be rewarded with lush flowers in the cold season.
Because azaleas originally come from mountain forests, they prefer a cool and humid climate. However, indoor azaleas were bred accordingly and can now also tolerate warmer and drier conditions, which usually prevail in our apartments.
Find a bright spot for the azalea that only allows direct sunlight in the morning or evening. Ideally, the temperature should be between 12 and 18 °C. It is best to gradually get the plant used to the climate in the apartment after you have bought it. For this purpose, it is first placed in a cool and partially shaded place. Allow it little by little more light and warmth. At the beginning of the flowering period, the azalea can also be placed in a lighter, slightly sunnier location, which ensures an even bloom. A south-facing window or a window sill above the heating, on the other hand, are not suitable. It is too warm and too dry for the azalea here, and it does not tolerate draughts. The indoor azaleas like to spend the summer in a sheltered, slightly shady place outdoors.
The azalea is something special when it comes to substrate. It needs an acidic soil and is very sensitive to lime. A special bog bed substrate, such as our Plantura organic acidic soil, is ideal. With a pH value of 4.0 to 6.0, this is in the acidic range and thus meets the requirements of the azalea. Our peat-reduced soil consists of natural raw materials and can be used both in beds and in pots. Fill the planter with a layer of expanded clay or pottery shards beforehand to improve water drainage. The substrate should always be kept moist and never dry out or waterlogged. Preferably use lime-free tap water or rainwater for watering.
Tip: Since azaleas like high humidity despite being cultivated, you should spray the azaleas in the pot regularly with lime-free water and avoid the blossoms.
Planting azaleas in the garden
Some species do best outdoors and due to theirSpend the whole year outside frost hardy.
If you want to plant an azalea in the garden, a bright or partially shaded spot without direct sun is ideal. The ideal azalea planting time is between September and November or between March and May. Dig a planting hole that is about four times the diameter of the root ball, as azaleas have extremely shallow and wide roots. Fill the approximately 40 cm deep hole with an acidic substrate to provide the azalea bush with optimal conditions. Now everything is soaked with lime-free water so that the peat can soak up the water. Finally, the azalea is placed in this swampy water-substrate mixture. If necessary, fill up with more substrate and model a pouring edge in order to be able to water optimally. The soil should be kept moist throughout the year. If you want to plant several azaleas, the planting distance should be between 30 and 100 cm depending on the species and growth. In addition to regular watering, azaleas should be fertilized to provide them with nutrients. A special fertilizer for rhododendrons and azaleas that maintains the acidity of the substrate is particularly suitable for this - for example our Plantura organic hydrangea fertilizer.
Wintering azaleas: Which azaleas are hardy?
Not all azalea species are hardy. The frost hardiness basically depends on whether the species is deciduous or not. Deciduous species are mostly intended for keeping outdoors and at the same time hardy. That means they can just stay outside in the winter. Evergreen azaleas are intended for indoor use and are not frost hardy. They must be overwintered in a cool and light place. Japanese azaleas and diamond azaleas, on the other hand, are outdoor azaleas that largely retain their foliage even in winter. Like the deciduous azaleas, they are frost hardy.
Wintering azalea indoors
Azalea houseplants need a cool and light spot in winter. The temperature can then drop to as little as 8 °C. Sufficient light is important at this time. Before you put the azalea in its winter place, you should remove all dead flowers and fruit buds. In the spring, it is then ideally placed outside so that it can shine again in the next flowering period.
Wintering azalea outdoors
The garden azaleas are hardy and can stay outside in winter. To make the cold season a little more pleasant for them, a layer of mulch is requiredAdvantage. This can consist of leaves, for example. Mulch protects the soil and thus the roots from frost. A layer of mulch is also useful in summer, as less water evaporates and the growth of weeds is inhibited. If the azalea is outside in the bucket, you can also mulch it here and wrap the pot in a jute sack or something similar.
Propagation of Azaleas
The easiest way to propagate your azalea is to take cuttings. To do this, cut off slightly woody shoots that are about 15 to 20 cm long. The best time for propagation is in early summer for indoor azaleas and from July to mid-September for garden azaleas. Use a sharp knife and cut as diagonally as possible to enlarge the cut surface. Water and nutrients are soon absorbed here. The shoots should have leaves but no flower buds. The leaves are cut off except for the upper pair. Since the cuttings do not root as easily, the use of rooting powder is recommended. This stimulates root formation with the help of special plant hormones. Put the cuttings in pure white peat with a pH of 4.0 - 4.5, which you moisten well. Alternatively, a dark container can be filled with water and the cuttings placed there to root. Now put a plastic bag over the pot to increase the humidity. This creates optimal conditions for the young plant. Finally, put the jar in a bright and warm place.
Tip: Azaleas can also be propagated using layering. With this method, the daughter plants initially remain on the mother plant and are only separated after root formation.
In addition, the azalea can be propagated by seed if fertilization has taken place. Detach the seeds from the capsules and spread the seeds directly on a suitable, acidic substrate. Since azaleas germinate in the sun, the seeds should not disappear under the substrate. Put the whole thing in a bright place, around 20 to 25 °C. Be sure to keep the humidity high with the help of cling film or a transparent cover. Germination should begin after about two to three weeks.
Are azaleas poisonous?
Azaleas are poisonous, as are most rhododendrons. Plant parts should not be consumed by humans or pets. Gloves are also recommended for safety when gardening.
Common pests and diseases
The most common azalea pests include vine weevil and spider mites; the latter occur mainly in dry room air. Powdery mildew can also often cause an unsightly sight on the pretty ornamental plants. Some Rhododendron cultivars and species, such as Rhododendron bureavii, naturally have a mealy leaf coating that is not powdery mildew. Every now and then rhododendron planthoppers and rhododendron lace bugs appear and leave bright speckles on the leaves, from which they suck the sap. The fungus Phytophthora causes shoot death.
Would you like to find out more about the diverse azaleas? We explain how to care for azaleas and what you absolutely have to pay attention to so that keeping them is successful.