Azaleas (Rhododendron simsii) come from China and Japan. The popular flowering plants come in many different colors, with single or double flowers. There are hundreds of varieties. In the trade, however, there are usually comparatively few of them on offer. Indoor azaleas, unlike their outdoor cultivars, bloom from September to April. The flower colors range from white to pink to red. There are also small and large-flowered varieties.

Popular houseplant – and rightly so!

Indoor azaleas are one of the most popular indoor plants, especially in winter. However, many plant lovers are a little disappointed after buying them. The plants quickly lose their beauty. The flowers fall off quite quickly and what remains is a simple green plant. This is due to the wrong care, mostly in the wrong location. Many forget that azaleas need a cool location. They are grown in the nursery in the Kalthaus. In the warm living room, its beauty disappears very quickly. Flowers, buds and, ultimately, leaves say goodbye. It doesn’t have to be.

It is important to pay attention to quality when buying. The foliage must be dense, the growth dense and compact. You should see a lot of buds. The first flowers should just have opened.


Indoor azaleas are hybrids of the Rhododendron simsii. Many breeders try their hand at the plants, which is why new varieties are constantly emerging, not just white, pink or red, but also those in many nuances. They also don’t all bloom at the same time, but from autumn to spring.

  • ‘Madame De Croock’ – white, slightly double flower with red dots in the middle, flowers from November to February
  • ‘Alexander’ – red single flower, flowering from January to May
  • ‘Angelina’ – pure white, double flowers, flowering time February to May
  • ‘Antarctica’ – light purple single flowers, flowering from February to May
  • ‘Watercolor’ – pink-white simple flowers, very nice drawing, flowering from August to May
  • ‘Christine Matton’ – salmon colored single flowers, flowering from December to May
  • ‘Dame Melanie’ – delicate pink flowers with a white margin and darker flecks, flowering from March to May
  • ‘De Waele’s Favorite’ – pink single flower with a white border, flowering from March to May
  • ‘Friedhelm Scherrer Roze’ – light and dark pink single bloom from January to May
  • ‘Ilona’ – simple pink flower with a wide white margin, from August to May
  • Inga ‘- simple pink flower with a white border from August to May
  • ‘Queen Fabiola’ – simple white and orange-red flowers, very beautiful, flowers from February to May
  • ‘Sachsenstern’ – simple white flower with a delicate red border from February to May

Indoor azalea – care

The room azalea is not necessarily one of the most easy-care flowering plants. Usually you buy it when it has opened a few flowers and there are still many closed on the plant. After flowering, the azalea is usually disposed of. It doesn’t have to be like that. On the one hand, the flowering time can be extended a lot if the location is correct and, on the other hand, the plant can be brought to flowering again, after a period of rest, of course. The main thing is that the azalea can spend the summer outdoors.


In their homeland, azaleas thrive in cool, damp mountain forests. Then you can imagine how the plants should be in the house. The warm living room with a humidity of 30/40 percent is guaranteed to be the wrong place.

  • Put the plants in a cool room for three days after buying them, if necessary in partial shade.
  • A cool hallway or bedroom is ideal.
  • Temperatures between 8 and 16 ° C are favorable.
  • When it is in full bloom, the azalea can be placed in the warm living room.
  • It is important not to place them near the heating!
  • The windowsill over a heater is also not suitable.
  • Drafts are harmful, especially when the substrate is damp.
  • Direct sun is absolutely to be avoided, at most a little morning and evening sun.
  • If you want to enjoy your azalea in bloom, you can put it in the living room for a few hours during the day and cool it off again for the rest of the day. This way the plants also last longer.

Plant substrate

Azaleas need a special substrate, preferably bog soil. It is acidic, has a pH value between 4 and 4.5. If a substrate with too high a value is used, the nutrients that are added because they are needed for growth are fixed in the substrate. The azaleas cannot take them in.

  • A humus-rich and lime-free soil is favorable
  • If the azalea is in an acidic substrate, for example in rhododendron soil, watering with calcareous water in winter is not such a big problem. During this time it is often difficult to get rainwater.

Plant and repot

If you want to continue cultivating the azalea, it should be repotted. Otherwise it is not necessary. Then it is only repotted every few years.

  • Repot every two to three years.
  • Rhododendron soil is suitable as a substrate.
  • When repotting, you also cut back the fiber roots a little, but really only a little.
  • Alternatively, you can use normal potting soil and mix it with sand. Coffee grounds, finely chopped conifer needles or oak and walnut leaves are also added.

Watering and fertilizing

Azaleas like high humidity. This comes from the location in their homeland in the towering forests of China and Japan. So spraying is important. Azaleas are very sensitive to lime. It is best to water it with rainwater. When watering with calcareous water, chlorosis usually occurs.

  • The azalea needs a lot of water when placed in a warm room.
  • It is poured with softened and tempered water.
  • The root ball should always be slightly damp and not waterlogged.
  • Azaleas should be sprayed daily with warm water. It is important not to spray on the flowers!
  • It also makes sense to put the pots in a planter that is filled with water and pebbles.
  • Waterlogging is definitely unfavorable.

If the root ball dries out, it is advisable to submerge the root ball in the water so that it can soak up.

  • It is best to fertilize with a special liquid fertilizer for azaleas and rhododendrons.
  • It is fertilized outside of the flowering period, i.e. between spring and autumn and every 4 weeks.

To cut

It is only cut when the azalea has faded. Otherwise, only regularly faded flowers and leaves are cut out. This is important so that it does not rot.

  • After it has faded, it is cut back. At this time the plant is usually quite out of shape.
  • You cut back about 1/3.
  • Dead branches are completely removed.
  • Do not squeeze shoots.
  • Only cut with very clean scissors!
  • It is cut just above a resting eye or a leaf or side bud.
  • This preserves the shape and promotes bushy growth.


Most azaleas are discarded after flowering. That is sad and absolutely not necessary.

  • After flowering, the azalea is kept cool and light.
  • Before doing this, all seed pods are removed, should any have formed. They draw a lot of power from the plant.
  • You cut them back and repot them.
  • The location will remain that way until the end of May.
  • Then you can take the plant outside, but in the shade and very protected. The azalea can also be planted. Without this step there is no bloom.
  • Repotting can take place every two to three years.
  • Even now it is important to ensure that the bale is always moist. It should never dry out completely.
  • The buds form in late August to early September when nighttime temperatures drop.
  • It is important to give the azalea before the first night frosts. She comes to a cool place where she can develop well.


Propagation takes place through semi-lignified head cuttings. The young shoots are cut in early spring. A cutting 8 to 10 cm long is put into a special substrate, a mixture of two parts sand and one part peat. The substrate must be moistened. A transparent bag is placed over the pot, which ensures that there is a high level of humidity. The vessel is placed in partial shade. After 8 to 12 weeks, the cutting should have rooted. It can then be repotted in special soil.

Diseases and pests

Most indoor azaleas die from being kept too wet or too dry. You have to show a little sure instinct. The houseplants are not susceptible to disease, but if cared for incorrectly, they rarely survive a season.

  • If the location is too warm and dry, spider mites can appear.
  • If chlorosis occurs due to incorrect irrigation water, a special preparation such as Fetrilon will help.
  • Care mistakes quickly lead to aphids, spider mites or whitefly.
  • The azalea is particularly popular with thunderstorm flies. The larvae feed on young shoots, newly developing leaves and flower buds until they hatch. The damage is often discovered too late. The best way to fight the nuisances is with products based on neem oil. Nematodes are also possible.
  • In summer, when the azaleas are outside, weevils like to attack the plants. You can see the feeding marks on the leaves. The larvae attack the roots, which usually means the end of the plant. The beetles should be collected and the larvae fought with nematodes.

Room azaleas are beautiful. There are really great varieties. Often the beautiful bloom does not last because the plants are wrong in the warm living room. In addition, they are poured with hard water, usually too much or too little. The room azalea is not an entry-level plant. You need a knack for that. If you don’t care how long the flowering lasts, you can always get a plant. If it has faded, it just comes away. If you want to try to get the azalea to bloom again, you need patience, a little tact and an outdoor location in summer.

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